chunk to prevent overflows in kernel

* bumping TRL version

* apply upstream fixes to our custom fix

---------

Co-authored-by: Wing Lian <wing@axolotl.ai>

.github/workflows/multi-gpu-e2e.yml

@@ -4,6 +4,10 @@ on:
   pull_request:
     paths:
       - 'tests/e2e/multigpu/*.py'
+      - 'requirements.txt'
+      - 'setup.py'
+      - 'pyproject.toml'
+      - '.github/workflows/multi-gpu-e2e.yml'
   workflow_dispatch:
   schedule:
     - cron: '0 0 * * 1,4'  # Runs at 00:00 UTC every monday & thursday

cicd/multigpu.py

@@ -37,15 +37,11 @@ temp_dir = tempfile.mkdtemp()
 with open(pathlib.Path(temp_dir) / "Dockerfile", "w", encoding="utf-8") as f:
     f.write(dockerfile_contents)
 
-cicd_image = (
-    Image.from_dockerfile(
-        pathlib.Path(temp_dir) / "Dockerfile",
-        force_build=True,
-        gpu="A10G",
-    )
-    .env(df_args)
-    .pip_install("fastapi==0.110.0", "pydantic==2.6.3")
-)
+cicd_image = Image.from_dockerfile(
+    pathlib.Path(temp_dir) / "Dockerfile",
+    force_build=True,
+    gpu="A10G",
+).env(df_args)
 
 app = App("Axolotl CI/CD", secrets=[])
 

docs/config.qmd

@@ -407,7 +407,10 @@ save_total_limit: # Checkpoints saved at a time
 max_steps:
 
 # bool of whether to include tokens trainer per second in the training metrics. This iterates over the entire dataset once, so it takes some time.
-include_tokens_per_second:
+include_tokens_per_second: # Optional[bool]
+
+# whether to find batch size that fits in memory. Passed to underlying transformers Trainer
+auto_find_batch_size: # Optional[bool]
 
 eval_table_size: # Approximate number of predictions sent to wandb depending on batch size. Enabled above 0. Default is 0
 eval_max_new_tokens: # Total number of tokens generated for predictions sent to wandb. Default is 128

docs/lora_optims.qmd

@@ -12,6 +12,7 @@ to leverage operator fusion and tensor re-use in order to improve speed and redu
 memory usage during the forward and backward passes of these calculations.
 
 We currently support several common model architectures, including (but not limited to):
+
 - `llama`
 - `mistral`
 - `qwen2`
@@ -82,7 +83,7 @@ lora_o_kernel: true
 ## Requirements
 
 - One or more NVIDIA or AMD GPUs (in order to use the Triton kernels)
-    - AMD can be used with experimental Triton support by setting the environment variable `TORCH_ROCM_AOTRITON_ENABLE_EXPERIMENTAL=1`
+    - Note: Set `TORCH_ROCM_AOTRITON_ENABLE_EXPERIMENTAL=1` to enable [memory-efficient attention on AMD GPUs](https://github.com/ROCm/aotriton/issues/16#issuecomment-2346675491)
 - Targeted LoRA adapters cannot use Dropout
     - This may limit model expressivity / cause overfitting
 - Targeted LoRA adapters cannot have bias terms

requirements.txt

@@ -13,12 +13,12 @@ liger-kernel==0.5.2
 packaging==23.2
 
 peft==0.14.0
-transformers==4.48.3
+transformers==4.49.0
 tokenizers>=0.21.0
 accelerate==1.3.0
 datasets==3.2.0
 deepspeed==0.16.1
-trl==0.15.0
+trl==0.15.1
 
 optimum==1.16.2
 hf_transfer

src/axolotl/__init__.py

@@ -4,4 +4,4 @@ import pkgutil
 
 __path__ = pkgutil.extend_path(__path__, __name__)  # Make this a namespace package
 
-__version__ = "0.7.0"
+__version__ = "0.8.0.dev0"

src/axolotl/cli/cloud/modal_.py

@@ -123,8 +123,6 @@ class ModalCloud(Cloud):
         if env := self.get_env():
             image = image.env(env)
 
-        image = image.pip_install("fastapi==0.110.0", "pydantic==2.6.3")
-
         return image
 
     def get_secrets(self):

src/axolotl/core/trainers/grpo/trainer.py

@@ -78,7 +78,6 @@ class AxolotlGRPOTrainer(SchedulerMixin, GRPOTrainer):
             if is_peft_model(unwrapped_model):
                 unwrapped_model.merge_adapter()
                 state_dict = unwrapped_model.state_dict()
-                unwrapped_model.unmerge_adapter()
                 # Remove base_model and base_layer prefixes
                 state_dict = {
                     k.removeprefix("base_model.model.")
@@ -100,8 +99,10 @@ class AxolotlGRPOTrainer(SchedulerMixin, GRPOTrainer):
                 }
             else:
                 state_dict = unwrapped_model.state_dict()
-        if self.accelerator.is_main_process:
-            llm_model = (
-                self.llm.llm_engine.model_executor.driver_worker.model_runner.model
-            )
-            llm_model.load_weights(state_dict.items())
+            if self.accelerator.is_main_process:
+                llm_model = (
+                    self.llm.llm_engine.model_executor.driver_worker.model_runner.model
+                )
+                llm_model.load_weights(state_dict.items())
+            if is_peft_model(unwrapped_model):
+                unwrapped_model.unmerge_adapter()

src/axolotl/integrations/kd/topk_logprob/LICENSE.md

@@ -1,58 +0,0 @@
-### AXOLOTL COMMUNITY LICENSE AGREEMENT
-
-This Axolotl Community License Agreement (“Agreement”) is entered into by and between Axolotl AI Corp. (“Axolotl”) and
-any individual or entity (“Licensee”) who wishes to use the Software (as defined below) in accordance with the terms
-and conditions set forth in this Agreement.
-
-1.  Definitions
-    1.1 “Licensee” refers to any individual or entity who has obtained a copy of the Software under this Agreement.
-    1.2 “Plugin Integration” means independent integration software modules which may or may not be offered by Axolotl,
-        which may be licensed separately by their respective  authors and/or licensors.
-    1.3 “Software” refers to the specific sub-directory of the Axolotl, Inc. software located at
-        https://github.com/axolotl-ai-cloud/axolotl/tree/main/src/axolotl/integrations and its subdirectories which
-        permits Plugin Integrations to integrate with the Axolotl service.
-2.  Grant of License
-    2.1	Axolotl hereby grants Licensee a worldwide, non-exclusive, royalty-free, license to use, copy, modify, merge,
-        publish, distribute, sublicense, and/or otherwise exploit the Software, subject to the following conditions:
-        - Licensee must comply with all the terms and conditions of this Agreement.
-        - Licensee must include the original copyright notice and disclaimer of warranty in all copies or substantial
-          portions of the Software.
-    2.2 Licensee may use the Software for any lawful purpose, except as restricted in Section 3.
-3.  Restrictions
-    3.1 Licensee shall not use the Software for any activity that constitutes a commercial activity of offering for
-        free or for sale any services, platform, or equivalent  to third parties for the purposes of allowing such
-        third parties to fine-tune artificial intelligence models.
-    3.2 Licensee shall not:
-        - Use the Software for any illegal or unauthorized purpose.
-        - Reverse engineer, decompile, or disassemble the Software.
-        - Remove or modify any copyright, trademark, or other proprietary notices contained in the Software.
-        - Use the Software in a way that could damage, disable, overburden, or impair the functionality of the
-          Software or interfere with any third-party use of the Software.
-    3.3 Axolotl reserves the right to restrict certain Plugin Integrations for use with the Software. To the extent Licensee integrates a permitted, applicable Plugin Integration with the Software, Licensee shall comply with any additional terms and conditions imposed by the licensors of such Plugin Integration for use of such Plugin Integrations. Licensee shall contact Axolotl if it has questions about whether its use of the Software falls beyond the scope of this Agreement.
-4.  Intellectual Property Rights
-    4.1 Axolotl and its contributors retain all intellectual property rights in and to the Software. Licensee
-        acknowledges that this Agreement does not transfer any ownership rights or intellectual property rights to
-        Licensee.
-5.  Disclaimer of Warranty
-    5.1 THE SOFTWARE IS PROVIDED “AS IS,” WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED
-        TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT. IN NO EVENT SHALL
-        THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES, OR OTHER LIABILITY, WHETHER IN AN ACTION OF
-        CONTRACT, TORT, OR OTHERWISE, ARISING FROM, OUT OF, OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
-        DEALINGS IN THE SOFTWARE.
-6.  Termination
-    6.1 Axolotl may terminate this Agreement at any time if Licensee fails to comply with any of the terms and
-        conditions set forth herein. Upon termination, Licensee shall cease all use of the Software and destroy any
-        copies in its possession.
-7.  Governing Law
-    7.1 This Agreement shall be governed by and construed in accordance with the laws of the State of California,
-        without regards to conflicts of laws provisions thereof.
-8.  Entire Agreement
-    8.1 This Agreement constitutes the entire agreement between Axolotl and Licensee with respect to the subject matter
-        hereof and supersedes all prior or contemporaneous understandings or agreements between the parties concerning
-        the Software, whether written or oral. Axolotl may update the terms of this Agreement from time to time, and
-        Licensee’s continued use of the Software after any such updates shall constitute acceptance of updated terms
-        on a go-forward basis.  Axolotl will use commercially reasonable efforts to provide Licensee notice of any
-        material updates. By using the Software, Licensee acknowledges that it has read, understood, and agrees to be
-        bound by the terms and conditions of this Agreement.
-
-This Agreement was last updated on August 23, 2024.

src/axolotl/integrations/kd/topk_logprob/bench_kl.py

@@ -0,0 +1,391 @@
+"""
+benchmark utility helper for benchmarking the KL divergence triton kernel
+"""
+import gc
+import time
+
+import torch
+from torch.utils.benchmark import Timer
+
+from axolotl.integrations.kd.topk_logprob.forward_kl import loss as eager_loss
+from axolotl.integrations.kd.topk_logprob.forward_kl_triton import loss as triton_loss
+
+
+# pylint: disable=cell-var-from-loop
+def benchmark_kl_div_loss_with_backward():
+    # Test configurations
+    batch_sizes = [1, 4]
+    seq_lens = [64, 512, 2048, 4096, 8192]
+    vocab_size = 32000
+    top_k = 64
+
+    # Store results
+    results = []
+
+    # Run benchmarks
+    for batch_size in batch_sizes:
+        for seq_len in seq_lens:
+            # Generate random test data
+            torch.manual_seed(42)
+
+            # Create tensors with gradients
+            student_logits = torch.randn(
+                batch_size, seq_len, vocab_size, device="cuda", requires_grad=True
+            )
+            # pylint: disable=duplicate-code
+            target_token_ids = torch.randint(
+                0, vocab_size, (batch_size, seq_len, top_k), device="cuda"
+            )
+            target_logprobs_raw = torch.randn(batch_size, seq_len, top_k, device="cuda")
+            target_logprobs = torch.log_softmax(target_logprobs_raw, dim=-1)
+            target_mask = torch.randint(
+                0, 2, (batch_size, seq_len, top_k), device="cuda"
+            ).float()
+
+            # Clone student_logits for the two implementations
+            student_logits_ref = student_logits.clone().detach().requires_grad_(True)
+            student_logits_triton = student_logits.clone().detach().requires_grad_(True)
+
+            # Define functions for timing that include both forward and backward passes
+            def run_reference():
+                # Forward pass
+                loss_ref = eager_loss(
+                    student_logits_ref, target_token_ids, target_logprobs, target_mask
+                )
+                # Backward pass
+                loss_ref.backward()
+
+            def run_triton():
+                # Forward pass
+                # pylint: disable=duplicate-code
+                loss_triton = triton_loss(
+                    student_logits_triton,
+                    target_token_ids,
+                    target_logprobs,
+                    target_mask,
+                )
+                # Backward pass
+                loss_triton.backward()
+
+            # Benchmark reference implementation (forward + backward)
+            t0 = Timer(
+                stmt="run_reference()",
+                globals={
+                    "run_reference": run_reference,
+                },
+            )
+            # Reset gradients before timing
+            student_logits_ref.grad = None
+            ref_time = t0.timeit(10).median * 1000  # Convert to ms
+
+            # Benchmark Triton implementation (forward + backward)
+            t1 = Timer(
+                stmt="run_triton()",
+                globals={
+                    "run_triton": run_triton,
+                },
+            )
+            # Reset gradients before timing
+            student_logits_triton.grad = None
+            triton_time = t1.timeit(10).median * 1000  # Convert to ms
+
+            # Compute speedup
+            speedup = ref_time / triton_time if triton_time > 0 else float("inf")
+
+            # Store results
+            results.append(
+                {
+                    "batch_size": batch_size,
+                    "seq_len": seq_len,
+                    "reference_time_ms": ref_time,
+                    "triton_time_ms": triton_time,
+                    "speedup": speedup,
+                }
+            )
+
+            print(f"Batch size: {batch_size}, Seq len: {seq_len}")
+            print(f"  Reference time (fwd+bwd): {ref_time:.2f} ms")
+            print(f"  Triton time (fwd+bwd): {triton_time:.2f} ms")
+            print(f"  Speedup: {speedup:.2f}x")
+
+    return results
+
+
+def benchmark_forward_backward_separately():
+    """
+    Benchmark forward and backward passes separately to identify where the speedup comes from.
+    """
+    # Test configurations
+    batch_sizes = [1, 4, 8]
+    seq_lens = [64, 512, 2048]
+    vocab_size = 32000
+    top_k = 64
+
+    # Store results
+    detailed_results = []
+
+    # Run benchmarks
+    for batch_size in batch_sizes:
+        for seq_len in seq_lens:
+            # Generate random test data
+            torch.manual_seed(42)
+
+            # Create tensors with gradients
+            student_logits = torch.randn(
+                batch_size, seq_len, vocab_size, device="cuda", requires_grad=True
+            )
+            # pylint: disable=duplicate-code
+            target_token_ids = torch.randint(
+                0, vocab_size, (batch_size, seq_len, top_k), device="cuda"
+            )
+            target_logprobs_raw = torch.randn(batch_size, seq_len, top_k, device="cuda")
+            target_logprobs = torch.log_softmax(target_logprobs_raw, dim=-1)
+            target_mask = torch.randint(
+                0, 2, (batch_size, seq_len, top_k), device="cuda"
+            ).float()
+
+            # Clone student_logits for the two implementations
+            student_logits_ref = student_logits.clone().detach().requires_grad_(True)
+            student_logits_triton = student_logits.clone().detach().requires_grad_(True)
+
+            # Forward-only reference
+            def run_reference_forward():
+                with torch.no_grad():
+                    return eager_loss(
+                        student_logits_ref,
+                        target_token_ids,
+                        target_logprobs,
+                        target_mask,
+                    )
+
+            # Forward-only triton
+            def run_triton_forward():
+                with torch.no_grad():
+                    return triton_loss(
+                        student_logits_triton,
+                        target_token_ids,
+                        target_logprobs,
+                        target_mask,
+                    )
+
+            # Benchmark forward pass only
+
+            t0_fwd = Timer(
+                stmt="run_reference_forward()",
+                globals={
+                    "run_reference_forward": run_reference_forward,
+                },
+            )
+            ref_fwd_time = t0_fwd.timeit(10).median * 1000  # Convert to ms
+
+            t1_fwd = Timer(
+                stmt="run_triton_forward()",
+                globals={
+                    "run_triton_forward": run_triton_forward,
+                },
+            )
+            triton_fwd_time = t1_fwd.timeit(10).median * 1000  # Convert to ms
+
+            # Pre-compute losses for backward pass benchmarking
+            loss_ref = eager_loss(
+                student_logits_ref, target_token_ids, target_logprobs, target_mask
+            )
+            loss_triton = triton_loss(
+                student_logits_triton, target_token_ids, target_logprobs, target_mask
+            )
+
+            # Backward-only reference
+            def run_reference_backward():
+                student_logits_ref.grad = None
+                loss_ref.backward()
+
+            # Backward-only triton
+            def run_triton_backward():
+                student_logits_triton.grad = None
+                loss_triton.backward()
+
+            # Benchmark backward pass only
+            t0_bwd = Timer(
+                stmt="run_reference_backward()",
+                globals={
+                    "run_reference_backward": run_reference_backward,
+                },
+            )
+            ref_bwd_time = t0_bwd.timeit(10).median * 1000  # Convert to ms
+
+            t1_bwd = Timer(
+                stmt="run_triton_backward()",
+                globals={
+                    "run_triton_backward": run_triton_backward,
+                },
+            )
+            triton_bwd_time = t1_bwd.timeit(10).median * 1000  # Convert to ms
+
+            # Compute speedups
+            fwd_speedup = (
+                ref_fwd_time / triton_fwd_time if triton_fwd_time > 0 else float("inf")
+            )
+            bwd_speedup = (
+                ref_bwd_time / triton_bwd_time if triton_bwd_time > 0 else float("inf")
+            )
+            total_ref_time = ref_fwd_time + ref_bwd_time
+            total_triton_time = triton_fwd_time + triton_bwd_time
+            total_speedup = (
+                total_ref_time / total_triton_time
+                if total_triton_time > 0
+                else float("inf")
+            )
+
+            # Store results
+            detailed_results.append(
+                {
+                    "batch_size": batch_size,
+                    "seq_len": seq_len,
+                    "ref_forward_ms": ref_fwd_time,
+                    "triton_forward_ms": triton_fwd_time,
+                    "forward_speedup": fwd_speedup,
+                    "ref_backward_ms": ref_bwd_time,
+                    "triton_backward_ms": triton_bwd_time,
+                    "backward_speedup": bwd_speedup,
+                    "total_ref_ms": total_ref_time,
+                    "total_triton_ms": total_triton_time,
+                    "total_speedup": total_speedup,
+                }
+            )
+
+            print(f"Batch size: {batch_size}, Seq len: {seq_len}")
+            print(
+                f"  Forward: Reference={ref_fwd_time:.2f}ms, Triton={triton_fwd_time:.2f}ms, Speedup={fwd_speedup:.2f}x"
+            )
+            print(
+                f"  Backward: Reference={ref_bwd_time:.2f}ms, Triton={triton_bwd_time:.2f}ms, Speedup={bwd_speedup:.2f}x"
+            )
+            print(
+                f"  Total: Reference={total_ref_time:.2f}ms, Triton={total_triton_time:.2f}ms, Speedup={total_speedup:.2f}x"
+            )
+
+    return detailed_results
+
+
+def benchmark_memory_usage_with_backward():
+    # Test configurations
+    batch_sizes = [1, 2]
+    seq_len = 8192
+    vocab_size = 128000
+    top_k = 64
+
+    # Store results
+    mem_results = []
+
+    # Run benchmarks
+    for batch_size in batch_sizes:
+        # Generate random test data
+        torch.manual_seed(42)
+        student_logits = torch.randn(
+            batch_size, seq_len, vocab_size, device="cuda", requires_grad=True
+        )
+        target_token_ids = torch.randint(
+            0, vocab_size, (batch_size, seq_len, top_k), device="cuda"
+        )
+        target_logprobs_raw = torch.randn(batch_size, seq_len, top_k, device="cuda")
+        target_logprobs = torch.log_softmax(target_logprobs_raw, dim=-1)
+        target_mask = torch.randint(
+            0, 2, (batch_size, seq_len, top_k), device="cuda"
+        ).float()
+
+        # Clone student_logits for the implementations
+        student_logits_ref = student_logits.clone().detach().requires_grad_(True)
+        student_logits_triton = student_logits.clone().detach().requires_grad_(True)
+
+        # Measure PyTorch memory usage (forward + backward)
+        torch.cuda.reset_peak_memory_stats()
+        torch.cuda.synchronize()
+        loss_ref = eager_loss(
+            student_logits_ref, target_token_ids, target_logprobs, target_mask
+        )
+        loss_ref.backward()
+        torch.cuda.synchronize()
+        pytorch_mem = torch.cuda.max_memory_allocated() / (1024**2)  # Convert to MB
+
+        # Measure Triton memory usage (forward + backward)
+        torch.cuda.reset_peak_memory_stats()
+        torch.cuda.synchronize()
+        loss_triton = triton_loss(
+            student_logits_triton, target_token_ids, target_logprobs, target_mask
+        )
+        loss_triton.backward()
+        torch.cuda.synchronize()
+        triton_mem = torch.cuda.max_memory_allocated() / (1024**2)  # Convert to MB
+
+        # Measure Triton memory usage with different chunk sizes (forward + backward)
+        for n_chunks in [1, 2, 4, 8]:
+            student_logits_chunk = student_logits.clone().detach().requires_grad_(True)
+
+            torch.cuda.reset_peak_memory_stats()
+            torch.cuda.synchronize()
+            loss_chunk = triton_loss(
+                student_logits_chunk,
+                target_token_ids,
+                target_logprobs,
+                target_mask,
+            )
+            loss_chunk.backward()
+            torch.cuda.synchronize()
+            chunk_mem = torch.cuda.max_memory_allocated() / (1024**2)  # Convert to MB
+
+            mem_results.append(
+                {
+                    "batch_size": batch_size,
+                    "implementation": f"Triton (chunks={n_chunks})",
+                    "memory_mb": chunk_mem,
+                }
+            )
+
+        # Store results
+        mem_results.append(
+            {
+                "batch_size": batch_size,
+                "implementation": "PyTorch",
+                "memory_mb": pytorch_mem,
+            }
+        )
+
+        mem_results.append(
+            {
+                "batch_size": batch_size,
+                "implementation": "Triton (default)",
+                "memory_mb": triton_mem,
+            }
+        )
+
+        print(f"Batch size: {batch_size} (with backward pass)")
+        print(f"  PyTorch memory: {pytorch_mem:.2f} MB")
+        print(f"  Triton memory: {triton_mem:.2f} MB")
+        print(f"  Memory reduction: {(1 - triton_mem/pytorch_mem)*100:.2f}%")
+
+    return mem_results
+
+
+def main():
+    print("Running benchmarks with forward and backward passes...")
+    benchmark_kl_div_loss_with_backward()
+    clean()
+
+    print("\nRunning detailed forward/backward benchmarks...")
+    # benchmark_forward_backward_separately()
+    # clean()
+
+    print("\nRunning memory usage benchmarks with backward passes...")
+    benchmark_memory_usage_with_backward()
+    clean()
+
+
+def clean():
+    for _ in range(5):
+        gc.collect()
+        torch.cuda.empty_cache()
+        time.sleep(1)
+
+
+if __name__ == "__main__":
+    main()

src/axolotl/integrations/kd/topk_logprob/forward_kl.py

@@ -1,14 +1,16 @@
 # Copyright 2024 Axolotl AI. All rights reserved.
 #
-# This software may be used and distributed according to
-# the terms of the Axolotl Community License Agreement (the "License");
+# Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
 #
 # Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
-# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
-# License for the specific language governing permissions and limitations under
-# the License.
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
 
 """
 loss for top_k KL divergence

src/axolotl/integrations/kd/topk_logprob/forward_kl_triton.py

@@ -0,0 +1,750 @@
+"""
+Optimized Triton kernel for KL divergence loss between teacher and student models.
+"""
+# pylint: disable=invalid-name,unused-argument
+from typing import Optional, Tuple
+
+import torch
+import triton
+import triton.language as tl
+
+
+@triton.jit
+def fused_logsumexp_logprobs_kernel(
+    student_logits_ptr,  # Input logits in original dtype
+    student_logprobs_ptr,  # Output logprobs (float32)
+    token_ids_ptr,  # Token IDs for top-k
+    B,
+    S,
+    V,
+    K,  # batch size, seq len, vocab size, top-k
+    temperature,
+    stride_l_b,
+    stride_l_s,
+    stride_l_v,
+    stride_lp_b,
+    stride_lp_s,
+    stride_lp_k,
+    stride_t_b,
+    stride_t_s,
+    stride_t_k,
+    BLOCK_SIZE: tl.constexpr,
+):
+    """
+    Fused kernel that computes logsumexp and logprobs for topk tokens.
+    All computations are done in float32 for numerical stability.
+    """
+    # Program ID
+    pid = tl.program_id(0)
+    batch_idx = pid // S
+    seq_idx = pid % S
+
+    # Bounds check
+    if batch_idx >= B or seq_idx >= S:
+        return
+
+    # Compute logsumexp over the vocabulary
+    max_val = -float("inf")
+
+    # Phase 1: Find max value across vocabulary
+    for v_offset in range(0, V, BLOCK_SIZE):
+        # Create block indices and mask
+        block_size = min(BLOCK_SIZE, V - v_offset)
+        block_idx = tl.arange(0, BLOCK_SIZE)
+        mask = block_idx < block_size
+
+        # Load logits block and convert to float32 in-place
+        ptrs = (
+            student_logits_ptr
+            + batch_idx * stride_l_b
+            + seq_idx * stride_l_s
+            + (v_offset + block_idx) * stride_l_v
+        )
+        block_logits = tl.load(ptrs, mask=mask, other=-float("inf")).to(tl.float32)
+
+        # Apply temperature scaling if needed
+        if temperature != 1.0:
+            block_logits = block_logits / temperature
+
+        # Update max value
+        block_max = tl.max(block_logits, axis=0)
+        max_val = tl.maximum(max_val, block_max)
+
+    # Phase 2: Compute sum of exp(logits - max_val)
+    sum_exp = 0.0
+
+    for v_offset in range(0, V, BLOCK_SIZE):
+        # Create block indices and mask
+        block_size = min(BLOCK_SIZE, V - v_offset)
+        block_idx = tl.arange(0, BLOCK_SIZE)
+        mask = block_idx < block_size
+
+        # Load logits block and convert to float32 in-place
+        ptrs = (
+            student_logits_ptr
+            + batch_idx * stride_l_b
+            + seq_idx * stride_l_s
+            + (v_offset + block_idx) * stride_l_v
+        )
+        block_logits = tl.load(ptrs, mask=mask, other=-float("inf")).to(tl.float32)
+
+        # Apply temperature scaling if needed
+        if temperature != 1.0:
+            block_logits = block_logits / temperature
+
+        # Compute exp(logits - max_val) and add to sum
+        block_exp = tl.exp(block_logits - max_val)
+        sum_exp += tl.sum(block_exp * mask, axis=0)
+
+    # Compute final logsumexp
+    logsumexp = max_val + tl.log(sum_exp)
+
+    # Phase 3: Compute and store logprobs for the top-k tokens
+    token_ids_base = token_ids_ptr + batch_idx * stride_t_b + seq_idx * stride_t_s
+    logprobs_base = (
+        student_logprobs_ptr + batch_idx * stride_lp_b + seq_idx * stride_lp_s
+    )
+
+    for k in range(K):
+        # Load token ID for position k
+        token_id = tl.load(token_ids_base + k * stride_t_k)
+
+        # Load the corresponding logit and convert to float32
+        token_logit_ptr = (
+            student_logits_ptr
+            + batch_idx * stride_l_b
+            + seq_idx * stride_l_s
+            + token_id * stride_l_v
+        )
+        token_logit = tl.load(token_logit_ptr).to(tl.float32)
+
+        # Apply temperature scaling if needed
+        if temperature != 1.0:
+            token_logit = token_logit / temperature
+
+        # Compute logprob directly: logit - logsumexp
+        token_logprob = token_logit - logsumexp
+
+        # Store the result
+        tl.store(logprobs_base + k * stride_lp_k, token_logprob)
+
+
+@triton.jit
+def grad_softmax_kernel(
+    grad_student_logits_ptr,
+    target_token_ids_ptr,
+    teacher_probs_ptr,
+    student_probs_ptr,
+    mask_ptr,
+    B,
+    S,
+    V,
+    K,  # batch size, seq len, vocab size, top-k
+    scale,
+    stride_gl_b,
+    stride_gl_s,
+    stride_gl_v,
+    stride_t_b,
+    stride_t_s,
+    stride_t_k,
+    stride_p_b,
+    stride_p_s,
+    stride_p_k,
+    stride_sp_b,
+    stride_sp_s,
+    stride_sp_k,
+    stride_m_b,
+    stride_m_s,
+    stride_m_k,
+    BLOCK_SIZE: tl.constexpr,
+):
+    # Program ID
+    pid = tl.program_id(0)
+    batch_idx = pid // S
+    seq_idx = pid % S
+
+    # Bounds check
+    if batch_idx >= B or seq_idx >= S:
+        return
+
+    # Base pointers for this (batch, seq) pair
+    grad_logits_base = (
+        grad_student_logits_ptr + batch_idx * stride_gl_b + seq_idx * stride_gl_s
+    )
+    token_ids_base = (
+        target_token_ids_ptr + batch_idx * stride_t_b + seq_idx * stride_t_s
+    )
+    teacher_probs_base = (
+        teacher_probs_ptr + batch_idx * stride_p_b + seq_idx * stride_p_s
+    )
+    student_probs_base = (
+        student_probs_ptr + batch_idx * stride_sp_b + seq_idx * stride_sp_s
+    )
+    mask_base = mask_ptr + batch_idx * stride_m_b + seq_idx * stride_m_s
+
+    # Process each teacher probability one at a time, computing all gradients for it
+    for k in range(0, K):
+        # Load data for current position k
+        teacher_prob = tl.load(teacher_probs_base + k * stride_p_k)
+        student_prob_k = tl.load(student_probs_base + k * stride_sp_k)
+        mask_val = tl.load(mask_base + k * stride_m_k)
+
+        # Precompute the self-influence term (multiplied by scale)
+        self_term = teacher_prob * (1.0 - student_prob_k) * scale
+
+        # Calculate gradient contributions for all positions j
+        for j in range(0, K):
+            token_id_j = tl.load(token_ids_base + j * stride_t_k)
+            student_prob_j = tl.load(student_probs_base + j * stride_sp_k)
+            mask_j = tl.load(mask_base + j * stride_m_k)
+
+            # Calculate the masking factor
+            combined_mask = mask_val * mask_j
+
+            # Determine if this is a diagonal or off-diagonal term
+            is_k_equals_j = tl.where(k == j, 1.0, 0.0)
+
+            # Compute the gradient contribution
+            # For diagonal (k==j): -teacher_prob * (1-student_prob_k) * scale * mask
+            # For off-diagonal: -(-teacher_prob * student_prob_j) * scale * mask
+            grad_contribution = (
+                -(
+                    self_term * is_k_equals_j
+                    - teacher_prob * student_prob_j * scale * (1.0 - is_k_equals_j)
+                )
+                * combined_mask
+            )
+
+            # Atomically update the gradient for this token
+            tl.atomic_add(
+                grad_logits_base + token_id_j * stride_gl_v, grad_contribution
+            )
+
+
+@triton.jit
+def grad_topk_softmax_kernel(
+    grad_student_logits_ptr,
+    student_logits_ptr,
+    target_token_ids_ptr,
+    teacher_probs_ptr,
+    student_probs_ptr,
+    mask_ptr,
+    B,
+    S,
+    V,
+    K,  # batch size, seq len, vocab size, top-k
+    scale,
+    stride_gl_b,
+    stride_gl_s,
+    stride_gl_v,
+    stride_l_b,
+    stride_l_s,
+    stride_l_v,
+    stride_t_b,
+    stride_t_s,
+    stride_t_k,
+    stride_p_b,
+    stride_p_s,
+    stride_p_k,
+    stride_sp_b,
+    stride_sp_s,
+    stride_sp_k,
+    stride_m_b,
+    stride_m_s,
+    stride_m_k,
+    BLOCK_SIZE: tl.constexpr,
+):
+    # Program ID
+    pid = tl.program_id(0)
+    batch_idx = pid // S
+    seq_idx = pid % S
+
+    # Bounds check
+    if batch_idx >= B or seq_idx >= S:
+        return
+
+    # Base pointers for this (batch, seq) pair
+    grad_logits_base = (
+        grad_student_logits_ptr + batch_idx * stride_gl_b + seq_idx * stride_gl_s
+    )
+    # logits_base = student_logits_ptr + batch_idx * stride_l_b + seq_idx * stride_l_s
+    token_ids_base = (
+        target_token_ids_ptr + batch_idx * stride_t_b + seq_idx * stride_t_s
+    )
+    teacher_probs_base = (
+        teacher_probs_ptr + batch_idx * stride_p_b + seq_idx * stride_p_s
+    )
+    student_probs_base = (
+        student_probs_ptr + batch_idx * stride_sp_b + seq_idx * stride_sp_s
+    )
+    mask_base = mask_ptr + batch_idx * stride_m_b + seq_idx * stride_m_s
+
+    # Load all token IDs, probs and masks for this position
+    token_ids = tl.zeros([K], dtype=tl.int32)
+    teacher_probs = tl.zeros([K], dtype=tl.float32)
+    student_probs = tl.zeros([K], dtype=tl.float32)
+    masks = tl.zeros([K], dtype=tl.float32)
+
+    for k in range(K):
+        token_ids[k] = tl.load(token_ids_base + k * stride_t_k)
+        teacher_probs[k] = tl.load(teacher_probs_base + k * stride_p_k)
+        student_probs[k] = tl.load(student_probs_base + k * stride_sp_k)
+        masks[k] = tl.load(mask_base + k * stride_m_k)
+
+    # Process gradients for all tokens in this position
+    for k in range(K):
+        # token_id = token_ids[k]
+        mask_k = masks[k]
+
+        # Skip computation if mask is zero by multiplying gradient by mask
+        for j in range(K):
+            other_token_id = token_ids[j]
+            mask_j = masks[j]
+            combined_mask = mask_k * mask_j
+
+            # Compute gradient differently for diagonal vs off-diagonal entries
+            # Using * 1.0 to convert boolean to float
+            is_diagonal = tl.where(j == k, 1.0, 0.0)
+
+            # Self influence: gradient = teacher_prob * (1 - student_prob)
+            self_grad = teacher_probs[k] * (1.0 - student_probs[k]) * is_diagonal
+
+            # Cross influence: gradient = -teacher_prob[k] * student_prob[j]
+            cross_grad = -teacher_probs[k] * student_probs[j] * (1.0 - is_diagonal)
+
+            # Combined gradient scaled by mask
+            grad_val = (self_grad + cross_grad) * scale * combined_mask
+
+            tl.atomic_add(grad_logits_base + other_token_id * stride_gl_v, grad_val)
+
+
+# Triton-accelerated implementation of KL divergence loss for top-k tokens
+# Chunking helper functions for handling long sequences
+def chunk_tensor(
+    tensor: torch.Tensor, max_seq_len: int
+) -> Tuple[torch.Tensor, Optional[int]]:
+    """Split a tensor along sequence dimension if needed."""
+    _, seq_len, *__ = tensor.shape
+
+    if seq_len <= max_seq_len:
+        return tensor, None
+
+    num_chunks = (seq_len + max_seq_len - 1) // max_seq_len
+    chunks = []
+
+    for i in range(num_chunks):
+        start_idx = i * max_seq_len
+        end_idx = min((i + 1) * max_seq_len, seq_len)
+        chunks.append(tensor[:, start_idx:end_idx, ...])
+
+    return chunks, num_chunks
+
+
+def merge_chunks(chunks: list, original_shape: torch.Size):
+    """Merge chunks back into a single tensor with original shape."""
+    return torch.cat(chunks, dim=1)
+
+
+# Triton-accelerated implementation of KL divergence loss for top-k tokens
+class TopKKLDivergence(torch.autograd.Function):
+    """
+    Autograd function for KL divergence loss between top-k logprobs
+    with support for chunking to handle very long sequences.
+    """
+
+    # Max sequence length to process in a single kernel launch
+    # This is a tunable parameter that might need adjustment based on GPU memory
+    MAX_SEQ_LEN = 8192
+
+    @staticmethod
+    def forward(
+        ctx,
+        student_logits,
+        target_token_ids,
+        target_logprobs,
+        target_mask,
+        num_items_in_batch=-1,
+        kd_temperature=1.0,
+        top_k_before_softmax=0,
+    ):
+        """
+        Forward pass for KL divergence loss between top-k logprobs with chunking.
+        """
+        # Only convert target_logprobs to float, leave student_logits as is
+        target_logprobs = target_logprobs.float()
+
+        # Get dimensions
+        batch_size, _, vocab_size = student_logits.shape
+        _, teacher_seq_len, top_k = target_token_ids.shape
+
+        # Slice student logits to match teacher sequence length
+        student_logits_for_kd = student_logits[:, :teacher_seq_len, :]
+
+        # Store original values for backward pass
+        ctx.original_seq_len = teacher_seq_len
+        ctx.original_dtype = student_logits.dtype
+
+        # Apply chunking for long sequences
+        if teacher_seq_len > TopKKLDivergence.MAX_SEQ_LEN:
+            # Chunk the inputs
+            student_logits_chunks, num_chunks = chunk_tensor(
+                student_logits_for_kd, TopKKLDivergence.MAX_SEQ_LEN
+            )
+            target_token_ids_chunks, _ = chunk_tensor(
+                target_token_ids, TopKKLDivergence.MAX_SEQ_LEN
+            )
+            # target_logprobs_chunks, _ = chunk_tensor(
+            #     target_logprobs, TopKKLDivergence.MAX_SEQ_LEN
+            # )
+            # target_mask_chunks, _ = chunk_tensor(
+            #     target_mask, TopKKLDivergence.MAX_SEQ_LEN
+            # )
+
+            # Process each chunk
+            student_logprobs_chunks = []
+            student_probs_chunks = []
+
+            for i in range(num_chunks):
+                chunk_logits = student_logits_chunks[i]
+                chunk_token_ids = target_token_ids_chunks[i]
+                chunk_seq_len = chunk_logits.shape[1]
+
+                if top_k_before_softmax:
+                    # Apply temperature to student logits
+                    if kd_temperature != 1.0:
+                        chunk_logits = chunk_logits / kd_temperature
+
+                    # Gather student logits for top-k tokens
+                    chunk_logits_topk = torch.gather(
+                        chunk_logits, dim=-1, index=chunk_token_ids
+                    )
+
+                    # Compute softmax over gathered logits
+                    chunk_logprobs_topk = torch.log_softmax(chunk_logits_topk, dim=-1)
+                    chunk_probs_topk = torch.exp(chunk_logprobs_topk)
+                else:
+                    # Allocate output tensor for logprobs directly (always in float32)
+                    chunk_logprobs_topk = torch.empty(
+                        (batch_size, chunk_seq_len, top_k),
+                        dtype=torch.float32,
+                        device=chunk_logits.device,
+                    )
+
+                    # Launch fused kernel directly
+                    grid = (batch_size * chunk_seq_len,)
+                    fused_logsumexp_logprobs_kernel[grid](
+                        chunk_logits.contiguous(),
+                        chunk_logprobs_topk,
+                        chunk_token_ids.contiguous(),
+                        batch_size,
+                        chunk_seq_len,
+                        vocab_size,
+                        top_k,
+                        kd_temperature,
+                        chunk_logits.stride(0),
+                        chunk_logits.stride(1),
+                        chunk_logits.stride(2),
+                        chunk_logprobs_topk.stride(0),
+                        chunk_logprobs_topk.stride(1),
+                        chunk_logprobs_topk.stride(2),
+                        chunk_token_ids.stride(0),
+                        chunk_token_ids.stride(1),
+                        chunk_token_ids.stride(2),
+                        min(1024, triton.next_power_of_2(vocab_size)),
+                    )
+
+                    # Calculate probs from logprobs
+                    chunk_probs_topk = torch.exp(chunk_logprobs_topk)
+
+                # Store results
+                student_logprobs_chunks.append(chunk_logprobs_topk)
+                student_probs_chunks.append(chunk_probs_topk)
+
+            # Merge results
+            student_logprobs_topk = torch.cat(student_logprobs_chunks, dim=1)
+            student_probs_topk = torch.cat(student_probs_chunks, dim=1)
+
+            # Save chunking info for backward pass
+            ctx.used_chunking = True
+            ctx.num_chunks = num_chunks
+
+        else:
+            # Original code path for shorter sequences
+            if top_k_before_softmax:
+                # Apply temperature to student logits
+                if kd_temperature != 1.0:
+                    student_logits_for_kd = student_logits_for_kd / kd_temperature
+
+                # Gather student logits for top-k tokens
+                student_logits_topk = torch.gather(
+                    student_logits_for_kd, dim=-1, index=target_token_ids
+                )
+
+                # Compute softmax over gathered logits
+                student_logprobs_topk = torch.log_softmax(student_logits_topk, dim=-1)
+                student_probs_topk = torch.exp(student_logprobs_topk)
+            else:
+                # Allocate output tensor for logprobs directly (always in float32)
+                student_logprobs_topk = torch.empty(
+                    (batch_size, teacher_seq_len, top_k),
+                    dtype=torch.float32,
+                    device=student_logits.device,
+                )
+
+                # Launch fused kernel directly
+                grid = (batch_size * teacher_seq_len,)
+                fused_logsumexp_logprobs_kernel[grid](
+                    student_logits_for_kd.contiguous(),
+                    student_logprobs_topk,
+                    target_token_ids.contiguous(),
+                    batch_size,
+                    teacher_seq_len,
+                    vocab_size,
+                    top_k,
+                    kd_temperature,
+                    student_logits_for_kd.stride(0),
+                    student_logits_for_kd.stride(1),
+                    student_logits_for_kd.stride(2),
+                    student_logprobs_topk.stride(0),
+                    student_logprobs_topk.stride(1),
+                    student_logprobs_topk.stride(2),
+                    target_token_ids.stride(0),
+                    target_token_ids.stride(1),
+                    target_token_ids.stride(2),
+                    min(1024, triton.next_power_of_2(vocab_size)),
+                )
+
+                # Calculate probs from logprobs
+                student_probs_topk = torch.exp(student_logprobs_topk)
+
+            # No chunking used
+            ctx.used_chunking = False
+
+        # Save tensors for backward pass
+        ctx.save_for_backward(
+            student_logits_for_kd,
+            target_token_ids,
+            target_logprobs,
+            target_mask,
+            student_probs_topk,
+        )
+        ctx.kd_temperature = kd_temperature
+        ctx.top_k_before_softmax = top_k_before_softmax
+        ctx.num_items_in_batch = num_items_in_batch
+
+        # Convert mask to boolean
+        valid_mask = target_mask.bool()
+
+        # Extract valid tokens only - this is where the error was happening
+        # Use cloned contiguous tensors and explicit indexing for safety
+        student_logprobs_flat = student_logprobs_topk.view(-1, top_k)
+        target_logprobs_flat = target_logprobs.view(-1, top_k)
+        valid_mask_flat = valid_mask.view(-1, top_k)
+
+        # Gather valid indices explicitly to avoid illegal memory access
+        valid_indices = torch.nonzero(valid_mask_flat.view(-1)).squeeze(-1)
+        student_logprobs_valid = torch.index_select(
+            student_logprobs_flat.view(-1), 0, valid_indices
+        )
+        target_logprobs_valid = torch.index_select(
+            target_logprobs_flat.view(-1), 0, valid_indices
+        )
+
+        # Convert teacher logprobs to probabilities
+        teacher_probs_valid = torch.exp(target_logprobs_valid)
+
+        # Compute KL divergence loss
+        token_losses = teacher_probs_valid * (
+            target_logprobs_valid - student_logprobs_valid
+        )
+        kd_loss = token_losses.sum()
+
+        # Apply temperature scaling
+        # pylint: disable=duplicate-code
+        if kd_temperature != 1.0:
+            kd_loss = kd_loss * (kd_temperature**2)
+
+        # Normalize by number of items or valid tokens
+        if num_items_in_batch > 0:
+            kd_loss = kd_loss / float(num_items_in_batch)
+        else:
+            num_valid_tokens = valid_indices.numel()
+            kd_loss = kd_loss / float(num_valid_tokens if num_valid_tokens > 0 else 1)
+
+        return kd_loss
+
+    @staticmethod
+    def backward(ctx, grad_output):
+        """
+        Optimized backward pass for KL divergence loss with proper dtype handling and chunking.
+        """
+        (
+            student_logits,
+            target_token_ids,
+            target_logprobs,
+            target_mask,
+            student_probs,
+        ) = ctx.saved_tensors
+        kd_temperature = ctx.kd_temperature
+        num_items_in_batch = ctx.num_items_in_batch
+        original_dtype = ctx.original_dtype
+
+        # Get dimensions
+        batch_size, _, vocab_size = student_logits.shape
+        _, teacher_seq_len, top_k = target_token_ids.shape
+
+        # Initialize gradient tensor in float32 to support atomic operations
+        grad_student_logits = torch.zeros_like(student_logits, dtype=torch.float32)
+
+        # Compute scaling factor
+        scale = grad_output.item()
+
+        # Apply temperature scaling from forward pass
+        if kd_temperature != 1.0:
+            scale = scale * (kd_temperature**2)
+
+        # Normalize by number of items or valid tokens
+        if num_items_in_batch > 0:
+            scale = scale / float(num_items_in_batch)
+        else:
+            scale = scale / float(target_mask.sum().item())
+
+        # Apply chain rule for temperature scaling (1/temperature)
+        if kd_temperature != 1.0:
+            scale = scale / kd_temperature
+
+        # Convert teacher logprobs to probabilities
+        teacher_probs = torch.exp(target_logprobs)
+
+        # Use chunking for the backward pass if used in forward
+        if getattr(ctx, "used_chunking", False):
+            num_chunks = ctx.num_chunks
+            max_seq = TopKKLDivergence.MAX_SEQ_LEN
+
+            # Process each chunk
+            for i in range(num_chunks):
+                start_idx = i * max_seq
+                end_idx = min((i + 1) * max_seq, teacher_seq_len)
+                chunk_len = end_idx - start_idx
+
+                # Get chunk slices
+                # student_logits_chunk = student_logits[:, start_idx:end_idx, :]
+                target_token_ids_chunk = target_token_ids[:, start_idx:end_idx, :]
+                teacher_probs_chunk = teacher_probs[:, start_idx:end_idx, :]
+                student_probs_chunk = student_probs[:, start_idx:end_idx, :]
+                target_mask_chunk = target_mask[:, start_idx:end_idx, :]
+                grad_student_logits_chunk = grad_student_logits[:, start_idx:end_idx, :]
+
+                # Launch gradient computation kernel for this chunk
+                grid = (batch_size * chunk_len,)
+                grad_softmax_kernel[grid](
+                    grad_student_logits_chunk.contiguous(),
+                    target_token_ids_chunk.contiguous(),
+                    teacher_probs_chunk.contiguous(),
+                    student_probs_chunk.contiguous(),
+                    target_mask_chunk.contiguous(),
+                    batch_size,
+                    chunk_len,
+                    vocab_size,
+                    top_k,
+                    scale,
+                    grad_student_logits_chunk.stride(0),
+                    grad_student_logits_chunk.stride(1),
+                    grad_student_logits_chunk.stride(2),
+                    target_token_ids_chunk.stride(0),
+                    target_token_ids_chunk.stride(1),
+                    target_token_ids_chunk.stride(2),
+                    teacher_probs_chunk.stride(0),
+                    teacher_probs_chunk.stride(1),
+                    teacher_probs_chunk.stride(2),
+                    student_probs_chunk.stride(0),
+                    student_probs_chunk.stride(1),
+                    student_probs_chunk.stride(2),
+                    target_mask_chunk.stride(0),
+                    target_mask_chunk.stride(1),
+                    target_mask_chunk.stride(2),
+                    min(1024, triton.next_power_of_2(top_k)),
+                )
+
+                # Update the gradient tensor (already in-place)
+        else:
+            # Original code path for shorter sequences
+            # Launch gradient computation kernel
+            grid = (batch_size * teacher_seq_len,)
+            grad_softmax_kernel[grid](
+                grad_student_logits.contiguous(),
+                target_token_ids.contiguous(),
+                teacher_probs.contiguous(),
+                student_probs.contiguous(),
+                target_mask.contiguous(),
+                batch_size,
+                teacher_seq_len,
+                vocab_size,
+                top_k,
+                scale,
+                grad_student_logits.stride(0),
+                grad_student_logits.stride(1),
+                grad_student_logits.stride(2),
+                target_token_ids.stride(0),
+                target_token_ids.stride(1),
+                target_token_ids.stride(2),
+                teacher_probs.stride(0),
+                teacher_probs.stride(1),
+                teacher_probs.stride(2),
+                student_probs.stride(0),
+                student_probs.stride(1),
+                student_probs.stride(2),
+                target_mask.stride(0),
+                target_mask.stride(1),
+                target_mask.stride(2),
+                min(1024, triton.next_power_of_2(top_k)),
+            )
+
+        # Convert gradient back to original dtype if needed
+        if original_dtype != torch.float32:
+            grad_student_logits = grad_student_logits.to(original_dtype)
+
+        # Return gradients for student_logits and None for other inputs
+        return grad_student_logits, None, None, None, None, None, None
+
+
+# Wrapper function for chunked computation
+def loss(
+    student_logits: torch.Tensor,
+    target_token_ids: torch.Tensor,
+    target_logprobs: torch.Tensor,
+    target_mask: torch.Tensor,
+    num_items_in_batch: int = -1,
+    kd_temperature: float = 1.0,
+    top_k_before_softmax: int = 0,
+    max_seq_len: Optional[int] = None,
+):
+    """
+    Triton-accelerated Memory-efficient KL divergence loss computation for knowledge distillation
+    with support for very long sequences.
+
+    Args:
+        student_logits: Student logits [B, seq_len, vocab_size]
+        target_token_ids: Teacher token IDs [B, seq_len, top_k]
+        target_logprobs: Teacher logprobs [B, seq_len, top_k]
+        target_mask: Token mask [B, seq_len, top_k]
+        num_items_in_batch: Number of items for normalization (-1 for auto)
+        kd_temperature: Temperature for KD
+        top_k_before_softmax: Flag for softmax application order
+        max_seq_len: Override default MAX_SEQ_LEN value for chunking
+    """
+    # Allow overriding the max sequence length
+    if max_seq_len is not None and max_seq_len > 0:
+        TopKKLDivergence.MAX_SEQ_LEN = max_seq_len
+
+    total_loss = TopKKLDivergence.apply(
+        student_logits,
+        target_token_ids,
+        target_logprobs,
+        target_mask,
+        -1 if num_items_in_batch <= 0 else num_items_in_batch,
+        kd_temperature,
+        top_k_before_softmax,
+    )
+
+    return total_loss

src/axolotl/integrations/kd/topk_logprob/logsumexp.py

@@ -0,0 +1,67 @@
+"""
+Optimized Triton kernels for logsumexp
+"""
+# pylint: disable=invalid-name,unused-argument
+import triton
+import triton.language as tl
+
+
+# Helper function for computing logsumexp
+@triton.jit
+def logsumexp_kernel(
+    logits_ptr,
+    output_ptr,
+    B,
+    S,
+    V,  # batch size, seq len, vocab size
+    stride_b,
+    stride_s,
+    stride_v,
+    out_stride_b,
+    out_stride_s,
+    BLOCK_SIZE: tl.constexpr,
+):
+    # Program ID
+    # pylint: disable=duplicate-code
+    pid = tl.program_id(0)
+    batch_idx = pid // S
+    seq_idx = pid % S
+
+    # Bounds check
+    if batch_idx >= B or seq_idx >= S:
+        return
+
+    # Pointers
+    logits_base = logits_ptr + batch_idx * stride_b + seq_idx * stride_s
+
+    # Find maximum for numerical stability
+    max_val = -float("inf")
+    for v_offset in range(0, V, BLOCK_SIZE):
+        v_size = min(BLOCK_SIZE, V - v_offset)
+        mask = tl.arange(0, BLOCK_SIZE) < v_size
+
+        logits_block = tl.load(
+            logits_base + (v_offset + tl.arange(0, BLOCK_SIZE)) * stride_v,
+            mask=mask,
+            other=-float("inf"),
+        )
+        max_val = tl.maximum(max_val, tl.max(logits_block, axis=0))
+
+    # Compute sum of exp(logit - max_val)
+    sum_exp = 0.0
+    for v_offset in range(0, V, BLOCK_SIZE):
+        v_size = min(BLOCK_SIZE, V - v_offset)
+        mask = tl.arange(0, BLOCK_SIZE) < v_size
+
+        logits_block = tl.load(
+            logits_base + (v_offset + tl.arange(0, BLOCK_SIZE)) * stride_v,
+            mask=mask,
+            other=-float("inf"),
+        )
+        sum_exp += tl.sum(tl.exp(logits_block - max_val), axis=0)
+
+    # Compute logsumexp
+    result = max_val + tl.log(sum_exp)
+
+    # Store result
+    tl.store(output_ptr + batch_idx * out_stride_b + seq_idx * out_stride_s, result)

src/axolotl/integrations/kd/trainer.py

@@ -20,6 +20,7 @@ from axolotl.core.trainers.base import AxolotlTrainer
 
 from .topk_logprob.forward_kl import loss as topk_kd_loss
 from .topk_logprob.forward_kl import topk_kd_loss_with_zscore
+from .topk_logprob.forward_kl_triton import loss as topk_kd_loss_triton
 
 
 class AxolotlKDTrainer(AxolotlTrainer):
@@ -85,7 +86,12 @@ class AxolotlKDTrainer(AxolotlTrainer):
                 num_items_in_batch=num_items_in_batch,
             )
         else:
-            loss_kd = topk_kd_loss(
+            loss_fn = (
+                topk_kd_loss
+                if self.args.kd_top_k_before_softmax
+                else topk_kd_loss_triton
+            )
+            loss_kd = loss_fn(
                 shift_logits,
                 target_token_ids_for_loss,
                 target_logprobs_for_loss,

src/axolotl/monkeypatch/relora.py

@@ -127,6 +127,8 @@ class ReLoRACallback(TrainerCallback):
         optimizer: torch.optim.Optimizer,
         **_kwargs,
     ):
+        if not optimizer:
+            optimizer = state.optimizer
         if state.global_step > 0 and state.global_step % self.relora_steps == 0:
             checkpoint_folder = os.path.join(
                 args.output_dir,

src/axolotl/prompt_strategies/chat_template.py

@@ -272,8 +272,7 @@ class ChatTemplateStrategy(PromptTokenizingStrategy):
                 dict(zip(feature_names, row))
             )
             for key, val in tokenized_prompt.items():
-                for i in range(0, len(val), self.sequence_len):
-                    res[key].append(val[i : i + self.sequence_len])
+                res[key].append(val)
 
         # If there are no examples left, return an empty dictionary
         if not res:

src/axolotl/utils/config/models/input/v0_4_1/__init__.py

@@ -342,6 +342,7 @@ class LoraConfig(BaseModel):
     peft_use_dora: Optional[bool] = None
     peft_use_rslora: Optional[bool] = None
     peft_layer_replication: Optional[List[Tuple[int, int]]] = None
+    peft_init_lora_weights: Optional[Union[bool, str]] = None
 
     qlora_sharded_model_loading: Optional[bool] = Field(
         default=False,

src/axolotl/utils/data/utils.py

@@ -172,10 +172,11 @@ def drop_long_seq_in_dataset(dataset: Dataset, cfg: DictDefault):
     )
 
     try:
-        min_input_len = np.min(get_dataset_lengths(dataset))
-        LOG.debug(f"min_input_len: {min_input_len}")
-        max_input_len = np.max(get_dataset_lengths(dataset))
-        LOG.debug(f"max_input_len: {max_input_len}")
+        ds_lengths = get_dataset_lengths(dataset, from_arrow=True)
+        min_input_len = np.min(ds_lengths)
+        LOG.info(f"min_input_len: {min_input_len}")
+        max_input_len = np.max(ds_lengths)
+        LOG.info(f"max_input_len: {max_input_len}")
     except AttributeError:
         pass
 

src/axolotl/utils/models.py

@@ -1321,6 +1321,8 @@ def load_lora(model, cfg, inference=False, config_only=False):
     if loftq_bits:
         lora_config_kwargs["loftq_config"] = LoftQConfig(loftq_bits=loftq_bits)
         lora_config_kwargs["init_lora_weights"] = "loftq"
+    if cfg.peft_init_lora_weights:
+        lora_config_kwargs["init_lora_weights"] = cfg.peft_init_lora_weights
     if cfg.peft_use_dora:
         lora_config_kwargs["use_dora"] = cfg.peft_use_dora
         LOG.info("Initializing LoRA weights using dora. This might take longer.")

src/axolotl/utils/samplers/utils.py

@@ -4,13 +4,17 @@ helper util to calculate dataset lengths
 import numpy as np
 
 
-def get_dataset_lengths(dataset):
-    if "length" in dataset.data.column_names:
-        lengths = np.array(dataset.data.column("length"))
-    elif "position_ids" in dataset.data.column_names:
-        position_ids = dataset.data.column("position_ids")
+def get_dataset_lengths(dataset, from_arrow=False):
+    if "length" in dataset.column_names:
+        lengths = np.array(dataset["length"])
+    elif "position_ids" in dataset.column_names:
+        position_ids = dataset["position_ids"]
         lengths = np.array([x[-1] + 1 for x in position_ids])
     else:
-        input_ids = dataset.data.column("input_ids")
-        lengths = np.vectorize(len)(np.array(input_ids, dtype=object))
+        if from_arrow:
+            input_ids = dataset.data.column("input_ids")
+            lengths = np.vectorize(len)(np.array(input_ids, dtype=object))
+        else:
+            input_ids = dataset["input_ids"]
+            lengths = np.array([len(seq) for seq in input_ids])
     return lengths

tests/e2e/integrations/test_kd.py

@@ -90,6 +90,12 @@ class TestKnowledgeDistillation:
         check_tensorboard(
             temp_dir + "/runs", "train/loss", 1.0, "Train Loss is too high"
         )
+        check_tensorboard(
+            temp_dir + "/runs", "train/loss", 0.0, "Train Loss is too low", lt=False
+        )
+        check_tensorboard(
+            temp_dir + "/runs", "train/grad_norm", 8.0, "Train grad norm is too high"
+        )
 
     @pytest.mark.parametrize(
         "load_in_8bit",
@@ -121,3 +127,9 @@ class TestKnowledgeDistillation:
         check_tensorboard(
             temp_dir + "/runs", "train/loss", 1.0, "Train Loss is too high"
         )
+        check_tensorboard(
+            temp_dir + "/runs", "train/loss", 0.0, "Train Loss is too low", lt=False
+        )
+        check_tensorboard(
+            temp_dir + "/runs", "train/grad_norm", 8.0, "Train grad norm is too high"
+        )

tests/e2e/integrations/test_kl_loss.py

@@ -0,0 +1,163 @@
+"""
+sanity checks on kl loss and gradients
+"""
+import torch
+
+# Import both implementations
+from axolotl.integrations.kd.topk_logprob.forward_kl import loss as eager_loss
+from axolotl.integrations.kd.topk_logprob.forward_kl_triton import loss as triton_loss
+
+
+def test_kl_loss_gradient():
+    """Test that the gradient of the Triton implementation matches the eager implementation."""
+
+    # Set the random seed for reproducibility
+    torch.manual_seed(42)
+
+    # Create random inputs
+    batch_size = 2
+    seq_len = 3
+    vocab_size = 100
+    top_k = 5
+
+    # Generate random student logits
+    student_logits = torch.randn(
+        batch_size, seq_len, vocab_size, requires_grad=True, device="cuda"
+    )
+    student_logits_triton = student_logits.detach().clone().requires_grad_(True)
+
+    # Generate random target token IDs, ensuring they're valid indices
+    # pylint: disable=duplicate-code
+    target_token_ids = torch.randint(
+        0, vocab_size, (batch_size, seq_len, top_k), device="cuda"
+    )
+
+    # Generate random target logprobs (before normalization)
+    target_logprobs_raw = torch.randn(batch_size, seq_len, top_k, device="cuda")
+
+    # Normalize the target logprobs to ensure they form a valid distribution
+    target_logprobs = torch.log_softmax(target_logprobs_raw, dim=-1)
+
+    # Create a random mask with some tokens masked out
+    target_mask = torch.randint(
+        0, 2, (batch_size, seq_len, top_k), device="cuda"
+    ).float()
+
+    # Additional parameters
+    num_items_in_batch = batch_size * seq_len
+    kd_temperature = 1.0
+    top_k_before_softmax = 0  # Test both modes
+
+    # Compute the loss and gradients with eager implementation
+    loss_eager = eager_loss(
+        student_logits,
+        target_token_ids,
+        target_logprobs,
+        target_mask,
+        num_items_in_batch,
+        kd_temperature,
+        top_k_before_softmax,
+    )
+    loss_eager.backward()
+    grad_eager = student_logits.grad.clone()
+
+    # Reset gradients
+    student_logits.grad.zero_()
+
+    # Compute the loss and gradients with Triton implementation
+    loss_triton = triton_loss(
+        student_logits_triton,
+        target_token_ids,
+        target_logprobs,
+        target_mask,
+        num_items_in_batch,
+        kd_temperature,
+        top_k_before_softmax,
+    )
+    loss_triton.backward()
+    grad_triton = student_logits_triton.grad.clone()
+
+    # Compare loss values
+    print(f"Eager loss: {loss_eager.item()}")
+    print(f"Triton loss: {loss_triton.item()}")
+    loss_diff = abs(loss_eager.item() - loss_triton.item())
+    print(f"Loss difference: {loss_diff}")
+    assert loss_diff < 1e-5, "Loss values differ significantly!"
+
+    # Compare gradients
+    grad_diff = (grad_eager - grad_triton).abs().max().item()
+    print(f"Max gradient difference: {grad_diff}")
+
+    # Print some sample gradients
+    sample_idx = (0, 0, 0)  # (batch, seq, vocab)
+    print(f"Sample eager gradient: {grad_eager[sample_idx].item()}")
+    print(f"Sample triton gradient: {grad_triton[sample_idx].item()}")
+
+    # Compute relative difference for non-zero gradients
+    mask = grad_eager.abs() > 1e-10
+    if mask.sum() > 0:
+        rel_diff = (
+            (
+                (grad_eager[mask] - grad_triton[mask]).abs()
+                / (grad_eager[mask].abs() + 1e-10)
+            )
+            .max()
+            .item()
+        )
+        print(f"Max relative gradient difference: {rel_diff}")
+        assert rel_diff < 1e-3, "Gradients differ significantly!"
+
+    # Also test top_k_before_softmax = 1 mode
+    top_k_before_softmax = 1
+
+    # Reset the gradients
+    student_logits = torch.randn(
+        batch_size, seq_len, vocab_size, requires_grad=True, device="cuda"
+    )
+    student_logits_triton = student_logits.detach().clone().requires_grad_(True)
+
+    # Compute the loss and gradients with eager implementation
+    loss_eager = eager_loss(
+        student_logits,
+        target_token_ids,
+        target_logprobs,
+        target_mask,
+        num_items_in_batch,
+        kd_temperature,
+        top_k_before_softmax,
+    )
+    loss_eager.backward()
+    grad_eager = student_logits.grad.clone()
+
+    # Compute the loss and gradients with Triton implementation
+    loss_triton = triton_loss(
+        student_logits_triton,
+        target_token_ids,
+        target_logprobs,
+        target_mask,
+        num_items_in_batch,
+        kd_temperature,
+        top_k_before_softmax,
+    )
+    loss_triton.backward()
+    grad_triton = student_logits_triton.grad.clone()
+
+    # Compare gradients for top_k_before_softmax = 1
+    grad_diff = (grad_eager - grad_triton).abs().max().item()
+    print("\nWith top_k_before_softmax=1:")
+    print(f"Max gradient difference: {grad_diff}")
+
+    # Compute relative difference for non-zero gradients
+    mask = grad_eager.abs() > 1e-10
+    if mask.sum() > 0:
+        rel_diff = (
+            (
+                (grad_eager[mask] - grad_triton[mask]).abs()
+                / (grad_eager[mask].abs() + 1e-10)
+            )
+            .max()
+            .item()
+        )
+        assert (
+            rel_diff < 1e-3
+        ), f"Gradients differ significantly, Max relative gradient difference: {rel_diff}"

tests/e2e/integrations/test_logsumexp.py

@@ -0,0 +1,204 @@
+"""
+sanity checks on logsumexp kernel validity
+"""
+import torch
+import triton
+
+from axolotl.integrations.kd.topk_logprob.logsumexp import logsumexp_kernel
+
+
+# PyTorch implementation of logsumexp for reference
+def torch_logsumexp(logits):
+    """PyTorch implementation of logsumexp over last dimension"""
+    return torch.logsumexp(logits, dim=-1)
+
+
+# Wrapper function for Triton logsumexp kernel
+def triton_logsumexp(logits):
+    """Triton implementation of logsumexp over last dimension"""
+    B, S, V = logits.shape  # pylint: disable=invalid-name
+    output = torch.empty((B, S), dtype=torch.float32, device=logits.device)
+
+    grid = (B * S,)
+    logsumexp_kernel[grid](
+        logits.contiguous(),
+        output,
+        B,
+        S,
+        V,
+        logits.stride(0),
+        logits.stride(1),
+        logits.stride(2),
+        output.stride(0),
+        output.stride(1),
+        min(1024, triton.next_power_of_2(V)),
+    )
+
+    return output
+
+
+class TritonLogSumExp(torch.autograd.Function):
+    """
+    Wrap a custom autograd function to use the Triton logsumexp for gradient testing
+    """
+
+    @staticmethod
+    def forward(ctx, logits):
+        B, S, V = logits.shape  # pylint: disable=invalid-name
+        output = torch.empty((B, S), dtype=torch.float32, device=logits.device)
+
+        # Save inputs for backward pass
+        ctx.save_for_backward(logits)
+        ctx.shape = logits.shape
+
+        grid = (B * S,)
+        logsumexp_kernel[grid](
+            logits.contiguous(),
+            output,
+            B,
+            S,
+            V,
+            logits.stride(0),
+            logits.stride(1),
+            logits.stride(2),
+            output.stride(0),
+            output.stride(1),
+            min(1024, triton.next_power_of_2(V)),
+        )
+
+        return output
+
+    @staticmethod
+    def backward(ctx, grad_output):
+        (logits,) = ctx.saved_tensors
+
+        # For logsumexp, the gradient is softmax(input) * grad_output
+        # First compute the logsumexp
+        lse = TritonLogSumExp.apply(logits)
+
+        # Compute softmax by exponentiating differences
+        softmax_output = torch.exp(logits - lse.unsqueeze(-1))
+
+        # Compute gradient of logsumexp by multiplying the softmax output by the gradient
+        grad_input = softmax_output * grad_output.unsqueeze(-1)
+
+        return grad_input
+
+
+def test_logsumexp_values():
+    """Test that the Triton logsumexp implementation matches PyTorch's"""
+    # Set random seed for reproducibility
+    torch.manual_seed(42)
+
+    # Test with various input shapes
+    test_shapes = [
+        (2, 3, 10),  # small vocab
+        (4, 5, 100),  # medium vocab
+        (2, 2, 32000),  # large vocab (typical for LLMs)
+    ]
+
+    for shape in test_shapes:
+        # Create random input tensors
+        logits = torch.randn(shape, device="cuda", requires_grad=False)
+
+        # Compute logsumexp using both implementations
+        torch_result = torch_logsumexp(logits)
+        triton_result = triton_logsumexp(logits)
+
+        # Compare results
+        max_diff = (torch_result - triton_result).abs().max().item()
+        print(f"Shape {shape}, Max diff: {max_diff}")
+
+        # Assert that the results are very close
+        assert max_diff < 1e-5, f"Results differ for shape {shape}: max diff {max_diff}"
+
+
+def test_logsumexp_edge_cases():
+    """Test edge cases for numerical stability"""
+    # Set random seed for reproducibility
+    torch.manual_seed(42)
+
+    # Case 1: Very large values that might cause overflow
+    logits_large = torch.ones(2, 3, 100, device="cuda") * 1000
+
+    # Case 2: Very small values that might cause underflow
+    logits_small = torch.ones(2, 3, 100, device="cuda") * -1000
+
+    # Case 3: Mix of large and small values
+    logits_mixed = torch.zeros(2, 3, 100, device="cuda")
+    logits_mixed[:, :, 0] = 1000  # One very large value
+
+    # Case 4: All identical values
+    logits_identical = torch.ones(2, 3, 100, device="cuda") * 5
+
+    # Case 5: Extreme values with NaN check
+    logits_extreme = torch.cat(
+        [
+            torch.full((1, 3, 50), 1e10, device="cuda"),
+            torch.full((1, 3, 50), -1e10, device="cuda"),
+        ],
+        dim=0,
+    )
+
+    for i, logits in enumerate(
+        [logits_large, logits_small, logits_mixed, logits_identical, logits_extreme]
+    ):
+        # Compute logsumexp using both implementations
+        torch_result = torch_logsumexp(logits)
+        triton_result = triton_logsumexp(logits)
+
+        # Check for NaNs
+        assert not torch.isnan(
+            torch_result
+        ).any(), f"PyTorch produced NaNs for case {i+1}"
+        assert not torch.isnan(
+            triton_result
+        ).any(), f"Triton produced NaNs for case {i+1}"
+
+        # Compare results
+        max_diff = (torch_result - triton_result).abs().max().item()
+        print(f"Edge case {i+1}, Max diff: {max_diff}")
+
+        # For very extreme values, allow a bit more tolerance
+        if i == 4:  # extreme case
+            assert max_diff < 1e-2, f"Results differ too much for edge case {i+1}"
+        else:
+            assert max_diff < 1e-5, f"Results differ too much for edge case {i+1}"
+
+
+def test_logsumexp_gradients():
+    """Test that the gradients of Triton logsumexp match PyTorch's"""
+    # Set random seed for reproducibility
+    torch.manual_seed(42)
+
+    # Create input tensors with gradients enabled
+    shapes = [(2, 3, 10), (4, 5, 100)]
+
+    for shape in shapes:
+        # Create two identical tensors for PyTorch and Triton
+        logits_torch = torch.randn(shape, device="cuda", requires_grad=True)
+        logits_triton = logits_torch.clone().detach().requires_grad_(True)
+
+        # Forward pass
+        torch_output = torch_logsumexp(logits_torch)
+        triton_output = TritonLogSumExp.apply(logits_triton)
+
+        # Compare forward pass values
+        max_diff_forward = (torch_output - triton_output).abs().max().item()
+        assert max_diff_forward < 1e-5, f"Forward pass values differ for shape {shape}"
+
+        # Create random gradient
+        grad_output = torch.randn_like(torch_output)
+
+        # Backward pass
+        torch_output.backward(grad_output)
+        triton_output.backward(grad_output)
+
+        # Compare gradients
+        max_diff_grad = (logits_torch.grad - logits_triton.grad).abs().max().item()
+        print(f"Shape {shape}, Max gradient diff: {max_diff_grad}")
+
+        # Assert that gradients are very close
+        assert (
+            max_diff_grad < 1e-5
+        ), f"Gradients differ for shape {shape}: max diff {max_diff_grad}"

tests/e2e/utils.py

@@ -102,7 +102,11 @@ def is_hopper():
 
 
 def check_tensorboard(
-    temp_run_dir: str, tag: str, lt_val: float, assertion_err: str
+    temp_run_dir: str,
+    tag: str,
+    comparison_val: float,
+    assertion_err: str,
+    lt: bool = True,
 ) -> None:
     """
     helper function to parse and check tensorboard logs
@@ -112,10 +116,20 @@ def check_tensorboard(
     reader = SummaryReader(event_file)
     df = reader.scalars  # pylint: disable=invalid-name
     df = df[(df.tag == tag)]  # pylint: disable=invalid-name
-    if "%s" in assertion_err:
-        assert df.value.values[-1] < lt_val, assertion_err % df.value.values[-1]
+    if lt:
+        if "%s" in assertion_err:
+            assert df.value.values[-1] < comparison_val, (
+                assertion_err % df.value.values[-1]
+            )
+        else:
+            assert df.value.values[-1] < comparison_val, assertion_err
     else:
-        assert df.value.values[-1] < lt_val, assertion_err
+        if "%s" in assertion_err:
+            assert df.value.values[-1] > comparison_val, (
+                assertion_err % df.value.values[-1]
+            )
+        else:
+            assert df.value.values[-1] > comparison_val, assertion_err
 
 
 def check_model_output_exists(temp_dir: str, cfg: DictDefault) -> None:

tests/prompt_strategies/conftest.py

@@ -125,6 +125,12 @@ def fixture_llama3_tokenizer():
     return tokenizer
 
 
+@pytest.fixture(name="smollm2_tokenizer", scope="session", autouse=True)
+def fixture_smollm2_tokenizer():
+    tokenizer = AutoTokenizer.from_pretrained("HuggingFaceTB/SmolLM2-135M")
+    return tokenizer
+
+
 @pytest.fixture(name="mistralv03_tokenizer", scope="session", autouse=True)
 def fixture_mistralv03_tokenizer():
     tokenizer = AutoTokenizer.from_pretrained(

tests/prompt_strategies/test_dpo_chatml.py

@@ -0,0 +1,61 @@
+"""
+Tests for loading DPO preference datasets with chatml formatting
+"""
+import unittest
+
+import pytest
+
+from axolotl.prompt_strategies.dpo import load as load_dpo
+from axolotl.utils.data.rl import load_prepare_preference_datasets
+from axolotl.utils.dict import DictDefault
+
+
+@pytest.fixture(name="minimal_dpo_cfg")
+def fixture_cfg():
+    return DictDefault(
+        {
+            "base_model": "HuggingFaceTB/SmolLM2-135M",
+            "tokenizer_config": "HuggingFaceTB/SmolLM2-135M",
+            "rl": "dpo",
+            "learning_rate": 0.000001,
+            "micro_batch_size": 1,
+            "gradient_accumulation_steps": 1,
+            "special_tokens": {
+                "pad_token": "<|endoftext|>",
+            },
+            "sequence_len": 2048,
+        }
+    )
+
+
+class TestDPOChatml:
+    """
+    Test loading DPO preference datasets with chatml formatting
+    """
+
+    def test_default(self, minimal_dpo_cfg):
+        cfg = DictDefault(
+            {
+                "datasets": [
+                    {
+                        "path": "argilla/distilabel-intel-orca-dpo-pairs",
+                        "type": "chatml",
+                        "split": "train[:1%]",
+                    }
+                ]
+            }
+            | minimal_dpo_cfg
+        )
+
+        # test that dpo.load works
+        load_dpo("chatml", cfg)
+        # now actually load the datasets with the strategy
+        train_ds, _ = load_prepare_preference_datasets(cfg)
+        assert train_ds[0]["prompt"].startswith("<|im_start|>")
+        assert train_ds[0]["prompt"].endswith("<|im_start|>assistant\n")
+        assert "chosen" in train_ds[0]
+        assert "rejected" in train_ds[0]
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/test_packed_batch_sampler.py

@@ -7,6 +7,7 @@ from transformers import AutoTokenizer
 from axolotl.datasets import TokenizedPromptDataset
 from axolotl.prompt_strategies.completion import load
 from axolotl.utils.collators import V2BatchSamplerDataCollatorForSeq2Seq
+from axolotl.utils.data.utils import drop_long_seq_in_dataset
 from axolotl.utils.dict import DictDefault
 from axolotl.utils.samplers import MultipackBatchSampler, get_dataset_lengths
 
@@ -18,11 +19,6 @@ def fixture_tokenizer():
     return tokenizer
 
 
-@pytest.fixture(name="max_seq_length")
-def fixture_max_seq_length():
-    return 4096
-
-
 class TestBatchedSamplerPacking:
     """
     Test class for packing streaming dataset sequences
@@ -37,6 +33,7 @@ class TestBatchedSamplerPacking:
             (2, 2),
         ],
     )
+    @pytest.mark.parametrize("max_seq_length", [4096, 512])
     def test_packing(self, batch_size, num_workers, tokenizer, max_seq_length):
         import axolotl.monkeypatch.data.batch_dataset_fetcher  # pylint: disable=unused-import  # noqa: F401
 
@@ -62,6 +59,9 @@ class TestBatchedSamplerPacking:
             dataset,
         )
         train_dataset = concatenate_datasets([dataset_wrapper])
+
+        train_dataset = drop_long_seq_in_dataset(train_dataset, cfg)
+
         lengths = get_dataset_lengths(train_dataset)
         batch_sampler = MultipackBatchSampler(
             sampler=RandomSampler(train_dataset),
@@ -90,7 +90,7 @@ class TestBatchedSamplerPacking:
                 batch_idxs.extend(pack)
 
         for batch in loader:
-            assert len(batch["input_ids"]) <= batch_size * max_seq_length
+            assert batch["input_ids"].numel() <= batch_size * max_seq_length
             assert batch["input_ids"].shape[1] == max_seq_length
 
         original_idxs = set(range(len(train_dataset)))