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[None][fix] impl fused triton kernel for e8m0 resmooth (target release/1.2.0rc6.post1, cherry-pick from https://github.com/NVIDIA/TensorRT-LLM/pull/10327 and https://github.com/NVIDIA/TensorRT-LLM/pull/10770)#10771

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kaiyux merged 2 commits intoNVIDIA:release/1.2.0rc6.post1from
yuxianq:triton-resmooth-rc6.post1
Jan 19, 2026

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@yuxianq yuxianq commented Jan 17, 2026

Summary by CodeRabbit

  • Refactor
    • Improved FP8 quantization performance with optimized computation.
    • Updated quantization function signature with clearer parameter naming.
    • Removed deprecated per-block casting function.

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yuxianq and others added 2 commits January 17, 2026 04:57
…ry footprint (NVIDIA#10327)

Signed-off-by: Nekofish-L <liuxiangyang@mail.ustc.edu.cn>
Co-authored-by: Kanghwan <861393+karljang@users.noreply.github.com>
Signed-off-by: Yuxian Qiu <142763828+yuxianq@users.noreply.github.com>
Signed-off-by: Yuxian Qiu <142763828+yuxianq@users.noreply.github.com>
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yuxianq commented Jan 17, 2026

/bot run --disable-fail-fast

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coderabbitai bot commented Jan 17, 2026

📝 Walkthrough

Walkthrough

Replaces Python-based FP8 E4M3 per-block resmoothing logic with a Triton GPU kernel implementation. Updates resmooth_to_fp8_e8m0 function signature and removes the standalone per_block_cast_to_fp8_e8m0 function, shifting computation from Python to GPU.

Changes

Cohort / File(s) Summary
Triton Kernel Implementation for FP8 Resmoothing
tensorrt_llm/quantization/utils/fp8_utils.py
Introduces _resmooth_kernel Triton kernel for block-wise FP8 quantization; computes block-wise maxima, derives new UE8M0 scales via logarithmic ceil operations, and performs in-place requantization. Updates resmooth_to_fp8_e8m0 signature to accept weight_scale instead of sf and adds block_size parameter. Removes deprecated per_block_cast_to_fp8_e8m0 function entirely. Shifts control flow from Python-side reshaping and casting to GPU kernel-based in-place processing.

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🎯 4 (Complex) | ⏱️ ~40 minutes

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Check name Status Explanation
Title check ✅ Passed The title clearly identifies the main change: implementing a fused Triton kernel for e8m0 resmooth optimization, and includes release target and cherry-pick information.

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Actionable comments posted: 2

🤖 Fix all issues with AI agents
In `@tensorrt_llm/quantization/utils/fp8_utils.py`:
- Around line 109-133: Before launching _resmooth_kernel, validate that
weight_scale's last two dims match the expected grid tiles: compute M,K from
orig_shape, BLOCK_M,BLOCK_K from block_size and expected_tiles = (triton.cdiv(M,
BLOCK_M), triton.cdiv(K, BLOCK_K)); if weight_scale.shape[-2:] does not equal
expected_tiles, either raise a clear ValueError (including expected vs actual
and the symbols weight_scale, M, K, BLOCK_M, BLOCK_K) or reshape/pad
weight_scale to match before creating s_view so _resmooth_kernel's loads/stores
cannot go out-of-bounds.
- Around line 98-102: The function signature for resmooth_to_fp8_e8m0 currently
uses PEP 585 syntax "tuple[int, int]" which breaks on Python 3.8; update the
type annotation to use typing.Tuple (i.e., Tuple[int, int]) in the function
definition (resmooth_to_fp8_e8m0) so it is compatible with Python 3.8,
leveraging the existing Tuple import from typing.
🧹 Nitpick comments (1)
tensorrt_llm/quantization/utils/fp8_utils.py (1)

106-113: Avoid implicit device migration and ensure contiguity before view.
.cuda() moves tensors to the current device (may differ from weight.device) and the subsequent .view(...) will fail on non-contiguous inputs. Consider preserving the original device and using reshape or contiguous.

♻️ Proposed adjustment
-    weight = weight.cuda()
-    weight_scale = weight_scale.cuda()
+    device = weight.device if weight.is_cuda else torch.device("cuda")
+    weight = weight.to(device).contiguous()
+    weight_scale = weight_scale.to(device).contiguous()
...
-    w_view = weight.view(-1, M, K)
-    s_view = weight_scale.view(-1, weight_scale.shape[-2],
-                               weight_scale.shape[-1])
+    w_view = weight.reshape(-1, M, K)
+    s_view = weight_scale.reshape(-1, weight_scale.shape[-2],
+                                  weight_scale.shape[-1])

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PR_Github #32394 [ run ] triggered by Bot. Commit: 70d6113

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yuxianq commented Jan 17, 2026

/bot run --disable-fail-fast --add-multi-gpu-test

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PR_Github #32400 [ run ] triggered by Bot. Commit: 70d6113

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PR_Github #32400 [ run ] completed with state SUCCESS. Commit: 70d6113
/LLM/release-1.2.0rc6.post1/L0_MergeRequest_PR pipeline #7 completed with status: 'FAILURE'

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yuxianq commented Jan 17, 2026

/bot run --disable-fail-fast --add-multi-gpu-test

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PR_Github #32414 [ run ] triggered by Bot. Commit: 70d6113

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PR_Github #32414 [ run ] completed with state DISABLED
CI server is currently disabled for scheduled maintenance. Estimated completion time: 5 PM PST on 1/17.

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/bot run --disable-fail-fast --add-multi-gpu-test

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PR_Github #32423 [ run ] triggered by Bot. Commit: 70d6113

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PR_Github #32423 [ run ] completed with state SUCCESS. Commit: 70d6113
/LLM/release-1.2.0rc6.post1/L0_MergeRequest_PR pipeline #8 completed with status: 'FAILURE'

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yuxianq commented Jan 18, 2026

/bot run --disable-fail-fast --add-multi-gpu-test

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PR_Github #32441 [ run ] triggered by Bot. Commit: 70d6113

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PR_Github #32441 [ run ] completed with state SUCCESS. Commit: 70d6113
/LLM/release-1.2.0rc6.post1/L0_MergeRequest_PR pipeline #9 completed with status: 'FAILURE'

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kaiyux commented Jan 19, 2026

/bot run --disable-fail-fast --add-multi-gpu-test

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PR_Github #32492 [ run ] triggered by Bot. Commit: 70d6113

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yuxianq commented Jan 19, 2026

/bot run --disable-fail-fast --only-multi-gpu-test

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PR_Github #32493 [ run ] triggered by Bot. Commit: 70d6113

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yuxianq commented Jan 19, 2026

/bot skip --comment "skip CI since this emergent fix has been validated locally"

@kaiyux kaiyux enabled auto-merge (squash) January 19, 2026 03:31
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PR_Github #32505 [ skip ] triggered by Bot. Commit: 70d6113

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PR_Github #32505 [ skip ] completed with state SUCCESS. Commit: 70d6113
Skipping testing for commit 70d6113

@kaiyux kaiyux merged commit a01ddd4 into NVIDIA:release/1.2.0rc6.post1 Jan 19, 2026
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