Support output signals for overlapping for cutedsl gemm#1677
Support output signals for overlapping for cutedsl gemm#1677zhyncs merged 90 commits intoflashinfer-ai:mainfrom
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Summary of Changes
Hello @fzyzcjy, I'm Gemini Code Assist1! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!
This pull request enhances the cutedsl gemm implementation by introducing a robust output signaling mechanism. This feature allows the kernel to communicate the completion status of individual batched operations (referred to as "experts") through a dedicated dst_signals array. By integrating new low-level DSL operations for atomic updates and byte manipulation, and carefully adjusting the kernel's synchronization logic, the change provides a fine-grained way to manage dependencies in overlapping computations. This is particularly beneficial for optimizing performance in scenarios requiring asynchronous processing of multiple tasks, such as in Mixture-of-Experts architectures.
Highlights
- Atomic Signal Mechanism: Implemented a new mechanism to signal completion of work for individual batches (experts) using an optional
cute.Pointertodst_signals, enabling fine-grained synchronization. - New DSL Operations: Introduced
with_byte,read_byteforUint64manipulation andatomic_add_release_globalfor atomic increments in global memory, leveraging LLVM inline assembly. - Scheduler Integration: Modified
MaskedSchedulerParamsandMaskedSchedulerto accept and managedst_signals, updatingdsm_pending_packedanddsm_counterto track signal states for each batch. - Kernel Synchronization Logic: Adjusted the
kernel'sc_pipeline.producer_acquire()andproducer_tail()calls to conditionally wait for writes (read=False) whendst_signalsare enabled, ensuring proper synchronization before signaling. - Python API Extension: Extended the
grouped_gemm_nt_maskedfunction and related internal functions to accept an optionaldst_signalstensor, allowing users to enable and utilize this signaling feature. - Comprehensive Testing: Added new test cases to
test_cute_dsl_blockscaled_gemm.pyto verify the correctness of thedst_signalsfunctionality, including assertions on the final signal values.
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Code Review
This pull request introduces support for output signals in the cutedsl GEMM kernel, aimed at enabling better overlapping of computations. The changes are comprehensive, affecting the scheduler, the kernel implementation, and the public-facing API. New helper functions for byte manipulation and atomic operations are added. The core logic modification resides in the kernel's epilogue, which now includes conditional synchronization and atomic signaling. The associated tests have been updated to validate this new functionality. My review focuses on enhancing the maintainability of the complex new kernel logic by suggesting refactoring to reduce code duplication and simplify conditional structures. Overall, the changes appear logically sound and the new feature is well-tested.
📌 Description
sglang main contains prerequisite code now, thus I can extract related parts to sglang/flashinfer/deepep, as is shown here
🔍 Related Issues
🚀 Pull Request Checklist
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✅ Pre-commit Checks
pre-commitby runningpip install pre-commit(or used your preferred method).pre-commit install.pre-commit run --all-filesand fixed any reported issues.🧪 Tests
unittest, etc.).Reviewer Notes