Skip to content

Add benchmarking and testing for blockwise fp8 GEMM using Triton and … #2740

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
wants to merge 2 commits into
base: main
Choose a base branch
from

Conversation

romanwu10
Copy link

issue: #2713

  • Introduced a new benchmarking script to compare performance between Triton kernels and torch._scaled_mm for blockwise fp8 GEMM operations.
  • Added tests for correctness and performance of scaled_mm implementations, including various matrix sizes commonly used in LLMs.
  • Implemented scaled_mm kernels to support blockwise fp8 GEMM operations, preserving scaling precision.
  • Enhanced the Float8BlockwiseLinear class to support both Triton and scaled_mm backends.
  • Included error handling and edge case tests for the new implementations.

…torch._scaled_mm

- Introduced a new benchmarking script to compare performance between Triton kernels and torch._scaled_mm for blockwise fp8 GEMM operations.
- Added tests for correctness and performance of scaled_mm implementations, including various matrix sizes commonly used in LLMs.
- Implemented scaled_mm kernels to support blockwise fp8 GEMM operations, preserving scaling precision.
- Enhanced the Float8BlockwiseLinear class to support both Triton and scaled_mm backends.
- Included error handling and edge case tests for the new implementations.
Copy link

pytorch-bot bot commented Aug 12, 2025

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/ao/2740

Note: Links to docs will display an error until the docs builds have been completed.

This comment was automatically generated by Dr. CI and updates every 15 minutes.

Copy link

meta-cla bot commented Aug 12, 2025

Hi @romanywu!

Thank you for your pull request and welcome to our community.

Action Required

In order to merge any pull request (code, docs, etc.), we require contributors to sign our Contributor License Agreement, and we don't seem to have one on file for you.

Process

In order for us to review and merge your suggested changes, please sign at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need to sign the corporate CLA.

Once the CLA is signed, our tooling will perform checks and validations. Afterwards, the pull request will be tagged with CLA signed. The tagging process may take up to 1 hour after signing. Please give it that time before contacting us about it.

If you have received this in error or have any questions, please contact us at [email protected]. Thanks!

@meta-cla meta-cla bot added the CLA Signed This label is managed by the Facebook bot. Authors need to sign the CLA before a PR can be reviewed. label Aug 12, 2025
Copy link

meta-cla bot commented Aug 12, 2025

Thank you for signing our Contributor License Agreement. We can now accept your code for this (and any) Meta Open Source project. Thanks!

Copy link
Contributor

@danielvegamyhre danielvegamyhre left a comment

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Thanks for taking a crack at this! I left a couple comments, there are some serious issues with this approach I think, we can't use other scaling types and other GEMMs as an approximation, we need to perform these benchmarks against torch._scaled_mm + CUDA 12.9 that dispatches to the actual cutlass kernel in PT core for groupwise+blockwise scaling.

a_fp8, a_scale, b_fp8, b_scale
)

# For now, use tensorwise scaling as a baseline comparison
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

I'm confused, why are we comparing against tensorwise here? Tensorwise will have substantially different perf than blockwise, we need to do a 1:1 comparison here

Blockwise fp8 GEMM using torch._scaled_mm instead of Triton kernel.

This is a simplified implementation that approximates blockwise scaling
using row-wise and column-wise scaling supported by torch._scaled_mm.
Copy link
Contributor

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

torch._scaled_mm supports DSV3 style groupwise and blockwise scaling now, using CUDA 12.9. We need to use that, we can't approximate

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
CLA Signed This label is managed by the Facebook bot. Authors need to sign the CLA before a PR can be reviewed.
Projects
None yet
Development

Successfully merging this pull request may close these issues.

2 participants