[Bugfix] Fix AWQ models batch invariance issues - #38670
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Code Review
This pull request updates determinism tests to use automatic data type selection and enhances the batch invariant mode. Key changes include adjusting Triton kernel block sizes for float16 to prevent shared memory overflows, implementing log-softmax for half-to-float conversions, and ensuring AWQ and Marlin quantization kernels are bypassed when batch invariance is enabled. Review feedback identifies a missing block size adjustment in the batched matrix multiplication logic and recommends moving an environment variable import out of a performance-critical path to minimize overhead.
| @@ -177,7 +177,7 @@ def grid(META): | |||
| }, | |||
| torch.float16: { | |||
| "BLOCK_SIZE_M": 128, | |||
| "BLOCK_SIZE_N": 256, | |||
| "BLOCK_SIZE_N": 128, # match the block size n of bfloat16 | |||
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The reduction of BLOCK_SIZE_N to 128 for torch.float16 is necessary to avoid shared memory overflow on SM 86 GPUs (like the RTX 3090). However, this change is missing in the configs dictionary within bmm_batch_invariant (line 703), which still uses 256. This will likely cause similar crashes when batched matrix multiplications are performed in batch invariant mode on these GPUs.
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I am not sure it is needed to change the BLOCK_SIZE_N in bmm_batch_invariant, I would appreciate the advice of the reviewers here.
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I recommend not to change it as it is tuned, is this a must-have for the fix?
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Yes and no. This is needed for SM 86 GPUs (e.g. RTX 3090 and other 80 series) which have 101KB shared memory per SM — the 256 config requires 106KB and crashes with OutOfResources error.
Perhaps we can make this conditional on SM number instead of changing the default?
If I remove that line and run the unit test on my machine I get:
----------------------- Captured stderr call ------------------------
[W401 23:15:51.385642307 Context.cpp:534] Warning: torch.backends.cuda.preferred_blas_library is an experimental feature. If you see any error or unexpected behavior when this flag is set please file an issue on GitHub. (function operator())
Loading safetensors checkpoint shards: 0% Completed | 0/1 [00:00<?, ?it/s]
Loading safetensors checkpoint shards: 100% Completed | 1/1 [00:00<00:00, 1.70it/s]
Loading safetensors checkpoint shards: 100% Completed | 1/1 [00:00<00:00, 1.70it/s]
(EngineCore pid=146608)
(EngineCore pid=146608) Process EngineCore:
(EngineCore pid=146608) Traceback (most recent call last):
(EngineCore pid=146608) File "/home/yusuf/.local/share/uv/python/cpython-3.12.13-linux-x86_64-gnu/lib/python3.12/multiprocessing/process.py", line 314, in _bootstrap
(EngineCore pid=146608) self.run()
(EngineCore pid=146608) File "/home/yusuf/.local/share/uv/python/cpython-3.12.13-linux-x86_64-gnu/lib/python3.12/multiprocessing/process.py", line 108, in run
(EngineCore pid=146608) self._target(*self._args, **self._kwargs)
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/v1/engine/core.py", line 1112, in run_engine_core
(EngineCore pid=146608) raise e
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/v1/engine/core.py", line 1082, in run_engine_core
(EngineCore pid=146608) engine_core = EngineCoreProc(*args, engine_index=dp_rank, **kwargs)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/tracing/otel.py", line 178, in sync_wrapper
(EngineCore pid=146608) return func(*args, **kwargs)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/v1/engine/core.py", line 848, in __init__
(EngineCore pid=146608) super().__init__(
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/v1/engine/core.py", line 124, in __init__
(EngineCore pid=146608) kv_cache_config = self._initialize_kv_caches(vllm_config)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/tracing/otel.py", line 178, in sync_wrapper
(EngineCore pid=146608) return func(*args, **kwargs)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/v1/engine/core.py", line 247, in _initialize_kv_caches
(EngineCore pid=146608) available_gpu_memory = self.model_executor.determine_available_memory()
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/v1/executor/abstract.py", line 136, in determine_available_memory
(EngineCore pid=146608) return self.collective_rpc("determine_available_memory")
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/v1/executor/uniproc_executor.py", line 80, in collective_rpc
(EngineCore pid=146608) result = run_method(self.driver_worker, method, args, kwargs)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/v1/serial_utils.py", line 510, in run_method
(EngineCore pid=146608) return func(*args, **kwargs)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/.venv/lib/python3.12/site-packages/torch/utils/_contextlib.py", line 124, in decorate_context
(EngineCore pid=146608) return func(*args, **kwargs)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/v1/worker/gpu_worker.py", line 370, in determine_available_memory
(EngineCore pid=146608) self.model_runner.profile_run()
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/v1/worker/gpu_model_runner.py", line 5810, in profile_run
(EngineCore pid=146608) output = self._dummy_sampler_run(last_hidden_states)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/.venv/lib/python3.12/site-packages/torch/utils/_contextlib.py", line 124, in decorate_context
(EngineCore pid=146608) return func(*args, **kwargs)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/v1/worker/gpu_model_runner.py", line 5591, in _dummy_sampler_run
(EngineCore pid=146608) logits = self.model.compute_logits(hidden_states)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/model_executor/models/qwen3.py", line 332, in compute_logits
(EngineCore pid=146608) logits = self.logits_processor(self.lm_head, hidden_states)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/.venv/lib/python3.12/site-packages/torch/nn/modules/module.py", line 1776, in _wrapped_call_impl
(EngineCore pid=146608) return self._call_impl(*args, **kwargs)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/.venv/lib/python3.12/site-packages/torch/nn/modules/module.py", line 1787, in _call_impl
(EngineCore pid=146608) return forward_call(*args, **kwargs)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/model_executor/layers/logits_processor.py", line 64, in forward
(EngineCore pid=146608) logits = self._get_logits(hidden_states, lm_head, embedding_bias)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/model_executor/layers/logits_processor.py", line 96, in _get_logits
(EngineCore pid=146608) logits = lm_head.quant_method.apply(lm_head, hidden_states, bias=embedding_bias)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/model_executor/layers/vocab_parallel_embedding.py", line 69, in apply
(EngineCore pid=146608) return dispatch_unquantized_gemm()(layer, x, layer.weight, bias)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/model_executor/layers/utils.py", line 98, in default_unquantized_gemm
(EngineCore pid=146608) return torch.nn.functional.linear(x, weight, bias)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/model_executor/layers/batch_invariant.py", line 913, in linear_batch_invariant
(EngineCore pid=146608) output = matmul_batch_invariant(input, weight.t())
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/model_executor/layers/batch_invariant.py", line 608, in matmul_batch_invariant
(EngineCore pid=146608) result = matmul_persistent(a, b)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/vllm/model_executor/layers/batch_invariant.py", line 196, in matmul_persistent
(EngineCore pid=146608) matmul_kernel_persistent[grid](
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/.venv/lib/python3.12/site-packages/triton/runtime/jit.py", line 370, in <lambda>
(EngineCore pid=146608) return lambda *args, **kwargs: self.run(grid=grid, warmup=False, *args, **kwargs)
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/.venv/lib/python3.12/site-packages/triton/runtime/jit.py", line 743, in run
(EngineCore pid=146608) launch_metadata = kernel.launch_metadata(grid, stream, *bound_args.values())
(EngineCore pid=146608) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/.venv/lib/python3.12/site-packages/triton/compiler/compiler.py", line 482, in launch_metadata
(EngineCore pid=146608) self._init_handles()
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/.venv/lib/python3.12/site-packages/triton/compiler/compiler.py", line 456, in _init_handles
(EngineCore pid=146608) raise_(OutOfResources(self.metadata.shared, max_shared, "shared memory"))
(EngineCore pid=146608) File "/home/yusuf/PycharmProjects/ym_vllm/vllm/.venv/lib/python3.12/site-packages/triton/compiler/compiler.py", line 448, in raise_
(EngineCore pid=146608) raise err
(EngineCore pid=146608) triton.runtime.errors.OutOfResources: out of resource: shared memory, Required: 106496, Hardware limit: 101376. Reducing block sizes or `num_stages` may help.There was a problem hiding this comment.
Hi @yewentao256, perhaps for this part we could introduce a per SM check and then decide the block size based on that? There exists a function: get_max_shared_memory_bytes() which returns the SM memory and could be used here? E.g. we query that when we run in batch invariant mode and then set the "BLOCK_SIZE_N": 128, IFF the user has < 106496 bytes on their SM version?
This would mean the memory issue is fixed across all GPUs not only for the 3090, as it would be hard to check per GPU or even per SM family as in SM 80 family, SM80 (A100) has 166,912 bytes and SM86 (3090) has 101,376 bytes.
How does that sound? I can put together an implementation and test it?
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I made a change in latest commit, which dynamically sets the block size now. Could you please test on h200 to confirm no regression?
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The unit tests pass on my 3090 with the new fi.
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Hi @yewentao256, this change is probably worth testing on newer hardware too. I only have a 3090 but if someone has a more recent GPU I would appreciate them trying the determinism unit tests on the Qwen/Qwen3-4B-AWQ model to validate it's not only my hardware in which the tests fail. |
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Thanks for the work!
Verified this works on H200 as well
| @@ -177,7 +177,7 @@ def grid(META): | |||
| }, | |||
| torch.float16: { | |||
| "BLOCK_SIZE_M": 128, | |||
| "BLOCK_SIZE_N": 256, | |||
| "BLOCK_SIZE_N": 128, # match the block size n of bfloat16 | |||
There was a problem hiding this comment.
I recommend not to change it as it is tuned, is this a must-have for the fix?
Happy to help! Nice, good to know it works on other hardware. Looking forward to getting this one fixed :) |
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This pull request has merge conflicts that must be resolved before it can be |
…through torch.matmul path so that it can be picked up by batch invariant kernels Signed-off-by: yusuf <yusuf@deeplearningmachine.mynet>
…marlin quantization method Signed-off-by: yusuf <yusuf@deeplearningmachine.mynet>
Signed-off-by: yusuf <yusuf@deeplearningmachine.mynet>
…th batch invariance Signed-off-by: yusuf <yusuf@deeplearningmachine.mynet>
Signed-off-by: yusuf <yusuf@deeplearningmachine.mynet>
Signed-off-by: yusuf <yusuf@deeplearningmachine.mynet> Signed-off-by: <>
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Hi @YM2132, the pre-commit checks have failed. Please run: uv pip install pre-commit>=4.5.1
pre-commit install
pre-commit run --all-filesThen, commit the changes and push to your branch. For future commits, Tip Is
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Signed-off-by: yusuf <yusuf@deeplearningmachine.mynet> Signed-off-by: <>
yewentao256
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LGTM, thanks for the work!
Nice! Thanks for the guidance @yewentao256 |
Signed-off-by: yusuf <yusuf@deeplearningmachine.mynet> Signed-off-by: <> Co-authored-by: yusuf <yusuf@deeplearningmachine.mynet>
Signed-off-by: yusuf <yusuf@deeplearningmachine.mynet> Signed-off-by: <> Co-authored-by: yusuf <yusuf@deeplearningmachine.mynet> Signed-off-by: Rishi Puri <riship@nvidia.com>
Signed-off-by: yusuf <yusuf@deeplearningmachine.mynet> Signed-off-by: <> Co-authored-by: yusuf <yusuf@deeplearningmachine.mynet>
Signed-off-by: yusuf <yusuf@deeplearningmachine.mynet> Signed-off-by: <> Co-authored-by: yusuf <yusuf@deeplearningmachine.mynet>
Signed-off-by: yusuf <yusuf@deeplearningmachine.mynet> Signed-off-by: <> Co-authored-by: yusuf <yusuf@deeplearningmachine.mynet>
Purpose
Enable AWQ quantized models to run with batch invariant mode (
VLLM_BATCH_INVARIANT=1).Fixes #29581
AWQ models currently fail batch invariance because vLLM auto-converts AWQ to the Marlin CUDA kernel, which bypasses the batch-invariant Triton matmul override.
This PR:
VLLM_BATCH_INVARIANT=1(awq_marlin.py)torch.matmulpath when batch invariant, so the Triton override can intercept it (awq.py)batch_invariant.pyexposed by AWQ using float16 (shared memory overflow on SM 86, unhandled_half_to_floatin log_softmax)dtypefrom"bfloat16"to"auto"so tests work with float16-only models like AWQTest Plan
Design notes
This is PR is a first attempt to get batch invariance working with AWQ models. We trade AWQ_Marlin performance for determinism. The dequant +
torch.matmulpath would be slower than fused Marlin but guarantees batch invariance.Open to feedback on:
override_quantization_methodor elsewherebatch_invariant.pyfixes should be a separate PRfrom vllm import envsposition in awq files)Essential Elements of an Effective PR Description Checklist
supported_models.mdandexamplesfor a new model.