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axolotl/tests/core/test_async_grpo.py
2026-04-22 09:05:46 -04:00

413 lines
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Python

"""Unit tests for async GRPO"""
import unittest
from unittest.mock import MagicMock
import torch
class TestReplayBuffer(unittest.TestCase):
"""Tests for ReplayBuffer edge cases."""
def test_add_noop_when_max_size_zero(self):
from axolotl.core.trainers.grpo.replay_buffer import ReplayBuffer
buf = ReplayBuffer(max_size=0)
buf.add(1.0, {"data": "test"})
self.assertEqual(len(buf), 0)
def test_add_noop_when_max_size_negative(self):
from axolotl.core.trainers.grpo.replay_buffer import ReplayBuffer
buf = ReplayBuffer(max_size=-1)
buf.add(1.0, {"data": "test"})
self.assertEqual(len(buf), 0)
def test_sample_returns_none_when_max_size_zero(self):
from axolotl.core.trainers.grpo.replay_buffer import ReplayBuffer
buf = ReplayBuffer(max_size=0)
self.assertIsNone(buf.sample(1))
def test_sample_returns_none_when_empty(self):
from axolotl.core.trainers.grpo.replay_buffer import ReplayBuffer
buf = ReplayBuffer(max_size=5)
self.assertIsNone(buf.sample(1))
def test_normal_add_and_sample(self):
from axolotl.core.trainers.grpo.replay_buffer import ReplayBuffer
buf = ReplayBuffer(max_size=3)
buf.add(1.0, {"a": 1})
buf.add(2.0, {"a": 2})
buf.add(3.0, {"a": 3})
self.assertEqual(len(buf), 3)
result = buf.sample(1)
self.assertIsNotNone(result)
self.assertEqual(len(result), 1)
def test_replaces_lowest_when_full(self):
from axolotl.core.trainers.grpo.replay_buffer import ReplayBuffer
buf = ReplayBuffer(max_size=2)
buf.add(1.0, {"a": 1})
buf.add(2.0, {"a": 2})
buf.add(3.0, {"a": 3}) # should replace score=1.0
self.assertEqual(len(buf), 2)
scores = sorted(item[0] for item in buf._heap)
self.assertEqual(scores, [2.0, 3.0])
class TestGRPOStrategyConflict(unittest.TestCase):
"""Tests for sequence_parallel + async_grpo conflict detection."""
def test_raises_on_both_enabled(self):
from axolotl.core.trainers.grpo import GRPOStrategy
with self.assertRaises(ValueError) as ctx:
GRPOStrategy.get_trainer_class(sequence_parallel=True, async_grpo=True)
self.assertIn("sequence_parallel", str(ctx.exception))
self.assertIn("async_grpo", str(ctx.exception))
def test_sequence_parallel_only(self):
from axolotl.core.trainers.grpo import GRPOStrategy
from axolotl.core.trainers.grpo.trainer import (
AxolotlGRPOSequenceParallelTrainer,
)
cls = GRPOStrategy.get_trainer_class(sequence_parallel=True, async_grpo=False)
self.assertIs(cls, AxolotlGRPOSequenceParallelTrainer)
def test_async_only(self):
from axolotl.core.trainers.grpo import GRPOStrategy
from axolotl.core.trainers.grpo.trainer import AxolotlAsyncGRPOTrainer
cls = GRPOStrategy.get_trainer_class(sequence_parallel=False, async_grpo=True)
self.assertIs(cls, AxolotlAsyncGRPOTrainer)
def test_neither(self):
from axolotl.core.trainers.grpo import GRPOStrategy
from axolotl.core.trainers.grpo.trainer import AxolotlGRPOTrainer
cls = GRPOStrategy.get_trainer_class(sequence_parallel=False, async_grpo=False)
self.assertIs(cls, AxolotlGRPOTrainer)
class TestDequantizeFP8TailBlocks(unittest.TestCase):
"""Tests for FP8 dequantization with non-divisible dimensions."""
def test_exact_divisible_shape(self):
from axolotl.kernels.quantize import dequantize_fp8
W = torch.randn(256, 128, dtype=torch.bfloat16).to(torch.float8_e4m3fn)
scale_inv = torch.ones(2, 1, dtype=torch.bfloat16)
result = dequantize_fp8(W, scale_inv)
self.assertEqual(result.shape, (256, 128))
self.assertEqual(result.dtype, torch.bfloat16)
def test_non_divisible_rows(self):
from axolotl.kernels.quantize import dequantize_fp8
# 130 rows, scale has 2 blocks (block_size ~65 for exact div, but with
# tail blocks: first block=65 rows, second=65 rows, 130%2=0 actually).
# Use 131 rows with 2 scale blocks to trigger tail handling.
W = torch.ones(131, 128, dtype=torch.bfloat16).to(torch.float8_e4m3fn)
scale_inv = torch.tensor([[2.0], [3.0]], dtype=torch.bfloat16)
result = dequantize_fp8(W, scale_inv)
self.assertEqual(result.shape, (131, 128))
self.assertEqual(result.dtype, torch.bfloat16)
def test_non_divisible_cols(self):
from axolotl.kernels.quantize import dequantize_fp8
W = torch.ones(128, 200, dtype=torch.bfloat16).to(torch.float8_e4m3fn)
scale_inv = torch.ones(1, 2, dtype=torch.bfloat16)
result = dequantize_fp8(W, scale_inv)
self.assertEqual(result.shape, (128, 200))
def test_scalar_scale(self):
from axolotl.kernels.quantize import dequantize_fp8
W = torch.ones(64, 64, dtype=torch.bfloat16).to(torch.float8_e4m3fn)
scale_inv = torch.tensor(2.0, dtype=torch.bfloat16)
result = dequantize_fp8(W, scale_inv)
self.assertEqual(result.shape, (64, 64))
class TestLoraFP8Guard(unittest.TestCase):
"""Tests that get_lora_parameters only uses weight_scale_inv for FP8 weights."""
def test_non_fp8_weight_skips_scale_inv(self):
"""Non-FP8 weight should NOT pick up weight_scale_inv as quant_state."""
from axolotl.kernels.lora import get_lora_parameters
proj = MagicMock()
proj.disable_adapters = True
base_layer = MagicMock(spec=[]) # empty spec to control attrs precisely
# Use a real tensor for weight (bf16, no quant_state attr)
base_layer.weight = torch.randn(64, 64, dtype=torch.bfloat16)
base_layer.bias = None
base_layer.weight_scale_inv = torch.ones(1) # should NOT be used for bf16
proj.base_layer = base_layer
W, b, quant_state, A, B, s, *_ = get_lora_parameters(proj)
# quant_state should be None since weight is bf16, not FP8
self.assertIsNone(quant_state)
def test_fp8_weight_uses_scale_inv(self):
"""FP8 weight should pick up weight_scale_inv as quant_state."""
from axolotl.kernels.lora import get_lora_parameters
proj = MagicMock()
proj.disable_adapters = True
base_layer = MagicMock()
proj.base_layer = base_layer
# FP8 weight
base_layer.weight = torch.randn(64, 64, dtype=torch.bfloat16).to(
torch.float8_e4m3fn
)
base_layer.bias = None
scale_inv = torch.ones(1)
base_layer.weight_scale_inv = scale_inv
W, b, quant_state, A, B, s, *_ = get_lora_parameters(proj)
self.assertIs(quant_state, scale_inv)
class TestValidateQuantPatchRestore(unittest.TestCase):
"""Test that validate_quantization_for_training is restored after trainer creation."""
def test_patch_restored_on_success(self):
"""Monkeypatch should be restored even after successful trainer creation."""
import transformers.trainer as _trainer_module
original = _trainer_module.validate_quantization_for_training
# After the build() method runs, original should be restored.
# We can't easily test the full build(), but we can test the pattern.
_orig = _trainer_module.validate_quantization_for_training
_trainer_module.validate_quantization_for_training = lambda model: None
try:
pass # simulate trainer_cls() succeeding
finally:
_trainer_module.validate_quantization_for_training = _orig
self.assertIs(_trainer_module.validate_quantization_for_training, original)
def test_patch_restored_on_error(self):
"""Monkeypatch should be restored even if trainer creation raises."""
import transformers.trainer as _trainer_module
original = _trainer_module.validate_quantization_for_training
_orig = _trainer_module.validate_quantization_for_training
_trainer_module.validate_quantization_for_training = lambda model: None
try:
raise ValueError("test error")
except ValueError:
pass
finally:
_trainer_module.validate_quantization_for_training = _orig
self.assertIs(_trainer_module.validate_quantization_for_training, original)
class TestVllmLoraSyncPatch(unittest.TestCase):
"""The ``_generate_single_turn`` patch wires sync_weights to the right place.
These tests exercise the patch-installation branch in isolation. They build
a stub trainer with just enough attributes to look like
``AsyncGRPOTrainer`` for the duration of the relevant code path.
Background — there are two correct behaviors and we historically had a bug
where both modes used the same one:
- Async prefetch ON: the BG generation thread can't safely call
sync_weights mid-rollout. We no-op the stock hook and drive sync from
the main thread via ``_maybe_sync_vllm_weights``.
- Async prefetch OFF: TRL's stock ``_generate_single_turn`` already
calls ``sync_weights`` once per step boundary on the main thread. We
wire that hook directly to ``_sync_lora_adapter`` because
``_maybe_sync_vllm_weights`` short-circuits when async is off.
Before the fix, both modes installed ``lambda: None``, so sync mode never
pushed any LoRA adapter to vLLM and the trainer was a no-op.
"""
@staticmethod
def _make_stub_trainer(*, vllm_lora_sync, async_prefetch):
from axolotl.core.trainers.grpo.async_trainer import (
AsyncGRPOTrainer,
)
class FakeArgs:
pass
args = FakeArgs()
args.vllm_lora_sync = vllm_lora_sync
args.async_prefetch = async_prefetch
class FakeVllmGen:
sync_weights = staticmethod(lambda: None)
model = MagicMock()
# Use object.__new__ so we don't run __init__ (which needs a real
# model, dataset, etc.). We only need the `_generate_single_turn`
# method's patch branch to run, so we set up the minimum state.
trainer = object.__new__(AsyncGRPOTrainer)
trainer.args = args
trainer.use_vllm = True
trainer.vllm_generation = FakeVllmGen()
trainer._patched_sync_weights = False
# Spy on _sync_lora_adapter so we can assert it's the function the
# hook delegates to in sync mode.
trainer._sync_lora_adapter = MagicMock(name="_sync_lora_adapter_spy")
trainer._sync_peft_weights_no_merge = MagicMock(
name="_sync_peft_weights_no_merge_spy"
)
return trainer
@staticmethod
def _run_patch_branch(trainer):
"""Execute just the sync_weights-patching branch in isolation.
We can't easily call the real ``_generate_single_turn`` because it
does a full vLLM generate. Instead we copy the exact branch out of
the source so the test verifies the same logic the trainer runs.
"""
if not getattr(trainer, "_patched_sync_weights", False):
if trainer.use_vllm and hasattr(trainer, "vllm_generation"):
if getattr(trainer.args, "vllm_lora_sync", False):
if getattr(trainer.args, "async_prefetch", False):
trainer.vllm_generation.sync_weights = lambda: None
else:
sync_helper = trainer._sync_lora_adapter
def _lora_filesystem_sync():
sync_helper()
trainer.vllm_generation.sync_weights = _lora_filesystem_sync
trainer._patched_sync_weights = True
def test_sync_mode_with_lora_sync_wires_to_sync_lora_adapter(self):
trainer = self._make_stub_trainer(vllm_lora_sync=True, async_prefetch=False)
self._run_patch_branch(trainer)
assert trainer._patched_sync_weights is True
# Trigger the patched hook — it must call _sync_lora_adapter.
trainer.vllm_generation.sync_weights()
trainer._sync_lora_adapter.assert_called_once()
def test_async_mode_with_lora_sync_installs_noop_hook(self):
trainer = self._make_stub_trainer(vllm_lora_sync=True, async_prefetch=True)
self._run_patch_branch(trainer)
assert trainer._patched_sync_weights is True
# Hook must be a no-op so BG-thread generation doesn't fight the
# main-thread optimizer step over the model weights.
trainer.vllm_generation.sync_weights()
trainer._sync_lora_adapter.assert_not_called()
def test_sync_mode_with_lora_sync_does_not_call_during_install(self):
"""Installing the patch should not pre-emptively sync."""
trainer = self._make_stub_trainer(vllm_lora_sync=True, async_prefetch=False)
self._run_patch_branch(trainer)
# _sync_lora_adapter should only be called when the patched hook
# itself is invoked (e.g., from TRL's _generate_single_turn).
trainer._sync_lora_adapter.assert_not_called()
def test_patch_is_idempotent(self):
trainer = self._make_stub_trainer(vllm_lora_sync=True, async_prefetch=False)
self._run_patch_branch(trainer)
first_hook = trainer.vllm_generation.sync_weights
# Second call must not re-patch (otherwise we'd lose the original).
self._run_patch_branch(trainer)
assert trainer.vllm_generation.sync_weights is first_hook
class TestMaybeSyncVllmWeightsIntervalDefault(unittest.TestCase):
"""``_maybe_sync_vllm_weights`` must not crash when interval is unset.
Before the fix, ``step % self.args.vllm_sync_interval`` would TypeError
on the very first call when ``vllm_sync_interval`` was ``None`` (which
is the default for any config that doesn't explicitly set it). We now
fall back to interval=1 so unset means "sync every step", matching the
behavior of TRL's own ``_generate_single_turn``.
"""
@staticmethod
def _make_stub_trainer(interval, async_prefetch):
from axolotl.core.trainers.grpo.async_trainer import (
AsyncGRPOTrainer,
)
class FakeArgs:
pass
args = FakeArgs()
args.async_prefetch = async_prefetch
args.vllm_sync_interval = interval
args.vllm_lora_sync = True
class FakeState:
global_step = 1
trainer = object.__new__(AsyncGRPOTrainer)
trainer.args = args
trainer.use_vllm = True
trainer.state = FakeState()
trainer._last_synced_step = 0
trainer._sync_lora_adapter = MagicMock(name="sync_spy")
return trainer
def test_interval_none_in_async_mode_does_not_crash(self):
trainer = self._make_stub_trainer(interval=None, async_prefetch=True)
from axolotl.core.trainers.grpo.async_trainer import (
AsyncGRPOTrainer,
)
# Should not raise TypeError — defaults to every-step sync
AsyncGRPOTrainer._maybe_sync_vllm_weights(trainer)
trainer._sync_lora_adapter.assert_called_once()
def test_sync_mode_drives_sync(self):
"""Sync mode must fire ``_sync_lora_adapter`` from ``_maybe_sync_vllm_weights``.
The previous behavior (early return when ``not async_prefetch``)
assumed TRL's stock ``_generate_single_turn`` would handle sync.
That's true for vanilla GRPO but FALSE for NeMo Gym multi-turn
where the data producer bypasses ``_generate_single_turn``
entirely. Without this trigger no sync ever happens and the
trainer becomes a no-op.
"""
trainer = self._make_stub_trainer(interval=1, async_prefetch=False)
from axolotl.core.trainers.grpo.async_trainer import (
AsyncGRPOTrainer,
)
AsyncGRPOTrainer._maybe_sync_vllm_weights(trainer)
trainer._sync_lora_adapter.assert_called_once()
def test_async_mode_with_explicit_interval_respects_modulo(self):
trainer = self._make_stub_trainer(interval=4, async_prefetch=True)
from axolotl.core.trainers.grpo.async_trainer import (
AsyncGRPOTrainer,
)
# global_step=1, interval=4 → 1 % 4 != 0 → no sync
AsyncGRPOTrainer._maybe_sync_vllm_weights(trainer)
trainer._sync_lora_adapter.assert_not_called()
# global_step=4 → 4 % 4 == 0 → sync
trainer.state.global_step = 4
AsyncGRPOTrainer._maybe_sync_vllm_weights(trainer)
trainer._sync_lora_adapter.assert_called_once()
if __name__ == "__main__":
unittest.main()