llama4 support (#2493)

* llama4 support

* add xet support [skip ci]

* be flexible on transformers version and skip test on version

* don't use deepspeed for the fix_untrained_tokens test

* reordering to trigger torch 2.6.0 tests first

* slightly smaller train set

* use 4.51.0 for now

* remove stray print, add llama4 chat template to schema, bump peft to 0.15.1

* patches to make llama4 performant

* add preliminary fp8 support

tests/e2e/multigpu/test_ray.py

@@ -31,7 +31,7 @@ class TestMultiGPURay:
         cfg = DictDefault(
             {
                 "base_model": "HuggingFaceTB/SmolLM2-135M",
-                "sequence_len": 2048,
+                "sequence_len": 1024,
                 "adapter": "lora",
                 "lora_r": 8,
                 "lora_alpha": 16,
@@ -94,8 +94,8 @@ class TestMultiGPURay:
                 "base_model": "HuggingFaceTB/SmolLM2-135M",
                 "sample_packing": True,
                 "pad_to_sequence_len": True,
-                "sequence_len": 2048,
-                "val_set_size": 0.05,
+                "sequence_len": 1024,
+                "val_set_size": 0.01,
                 "special_tokens": {
                     "pad_token": "<|endoftext|>",
                 },