(fix) fix rms_norm op #946
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Summary of Changes
Hello @SangChengC, 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 implements a fix for the rms_norm operation within the Triton kernel. The core change involves refining a specific heuristic parameter (num_warps) to ensure the stability and correct execution of this crucial normalization layer, which is vital for the performance and reliability of large language models.
Highlights
- RMSNorm Kernel Adjustment: The
num_warpsheuristic in thermsnorm_forwardTriton kernel has been adjusted. The maximum allowed warps were reduced from 8 to 4. This change likely addresses a stability or performance issue within therms_normoperation, particularly for thelightllmLlama model implementation.
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Code Review
This pull request fixes an issue in the rmsnorm Triton kernel by reducing the maximum number of warps from 8 to 4. My feedback focuses on improving the code's clarity by documenting the reason for this change, which will help with future maintenance.
| raise RuntimeError("This layer norm doesn't support feature dim >= 64KB.") | ||
| # heuristics for number of warps | ||
| num_warps = min(max(BLOCK_SIZE // 256, 1), 8) | ||
| num_warps = min(max(BLOCK_SIZE // 256, 1), 4) |
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The PR title suggests this change is a fix. It would be very helpful for future maintenance to add a brief inline comment explaining why the maximum number of warps is capped at 4. This provides context for why this specific value was chosen, for example, if it addresses a performance or stability issue on certain hardware.
| num_warps = min(max(BLOCK_SIZE // 256, 1), 4) | |
| num_warps = min(max(BLOCK_SIZE // 256, 1), 4) # Capped at 4 for performance/stability reasons |
No description provided.