Revert "Install pre-built xformers-0.0.32.post2 built with pt-2.9.0" #27714
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Code Review
This pull request reverts a previous change that used a pre-built xformers wheel, opting instead to build xformers from source within the Docker image. This is done by adding a RUN command to the Dockerfile for compilation and removing the xformers dependency from requirements/cuda.txt. However, the implementation has a critical flaw: the list of CUDA architectures for the xformers build is too restrictive. My review provides a specific suggestion to expand this list to ensure broader GPU compatibility (notably for Volta GPUs like V100) and improve performance on modern GPUs by including them for ahead-of-time compilation.
| # TODO (huydhn): Remove this once xformers is released for 2.9.0 | ||
| RUN --mount=type=cache,target=/root/.cache/uv bash - <<'BASH' | ||
| . /etc/environment | ||
| export TORCH_CUDA_ARCH_LIST='7.5 8.0+PTX 9.0a' |
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The hardcoded TORCH_CUDA_ARCH_LIST is overly restrictive and may cause compatibility and performance issues for users of the Docker image.
- Dropped Architectures: This list removes support for Volta (
7.0), which is used by V100 GPUs. This is a significant regression as V100s are still widely used in cloud environments and research. - Performance on Modern GPUs: It relies on just-in-time (JIT) compilation from PTX for modern architectures like Ada Lovelace (
8.9) and Hopper (9.0), as they are not explicitly listed. This can lead to significant startup delays when vLLM is first run on these GPUs. - Inconsistency: The default
torch_cuda_arch_listdefined as a build argument earlier in this Dockerfile (line 144) is much more comprehensive. While that argument is not available in this build stage, its value serves as a good reference for what architectures are generally supported.
To ensure broad compatibility and optimal performance, I recommend using a more inclusive list of architectures. This suggested list restores Volta support, provides ahead-of-time (AOT) compilation for common modern GPUs, and maintains forward compatibility for future architectures via PTX.
export TORCH_CUDA_ARCH_LIST='7.0 7.5 8.0 8.9 9.0a+PTX'
…llm-project#27714) Signed-off-by: Bhagyashri <Bhagyashri.Gaikwad2@ibm.com>
…vllm-project#27714) This reverts commit 9007bf5. Signed-off-by: Huy Do <huydhn@gmail.com>
Reverts #27598
Broke CUDA 13 build. https://buildkite.com/vllm/release/builds/9637/steps/canvas?sid=019a2dfc-911c-4783-b421-9d3acc153e1b