[ROCm] Fix TurboQuant on ROCm: backend routing, flash-attn compat, int64 overflow#39953
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Code Review
This pull request introduces routing for TurboQuant KV cache on ROCm and implements explicit int64 casting in Triton kernels for TurboQuant decode and store operations to ensure robust indexing. Additionally, a wrapper for flash_attn_varlen_func was added for ROCm; however, this wrapper should be updated to handle cases where the underlying function returns a tuple (e.g., when returning softmax or attention probabilities) to prevent potential type errors when copying results to the out tensor.
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Hi @aditi-amd check this PR please We've had to work on the same part of the code, let's see if we can implement it together :) |
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…flow Signed-off-by: aditi <aditi.rana@amd.com>
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BowenBao
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LGTM. cc @mgoin, @vibhavagarwal5 for review
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@JartX thanks for bringing this to our attention. Would it be okay if we landed our fix first? There’s a bit of overlap around flash-attn |
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Yes, that's correct. Please also check my PR; I'll resolve it as soon as they merge it. |
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LGTM, just want to fix the rocm.py change
Signed-off-by: aditi <aditi.rana@amd.com>
…t64 overflow (vllm-project#39953) Signed-off-by: aditi <aditi.rana@amd.com>
…t64 overflow (vllm-project#39953) Signed-off-by: aditi <aditi.rana@amd.com>
…t64 overflow (vllm-project#39953) Signed-off-by: aditi <aditi.rana@amd.com>
…t64 overflow (vllm-project#39953) Signed-off-by: aditi <aditi.rana@amd.com> Signed-off-by: Avinash Singh <avinashsingh.rcoem@gmail.com>
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Purpose
Route turboquant_* kv-cache-dtype to TurboQuantBackend on ROCm
Wrap flash_attn_varlen_func on ROCm to handle out= keyword argument (API mismatch with upstream flash-attn)
Cast block indices and slot offsets to int64 in Triton TQ decode/store kernels to prevent int32 overflow on large KV caches
Tests Done
Verified with GPT-OSS-120B on AMD MI300X (TP=2) at C=2, 4, 8, 64 with 8K input / 1K output — zero failures
Unit tests (tests/quantization/test_turboquant.py): 113 passed, 7 pre-existing failures (unrelated upstream issue)