fix(build): correct preprocessor guard for GDN decode to fix Ampere c… - #52743
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…ompilation fused_gdn_decode_post_conv_mtp was mistakenly placed inside the VLLM_ENABLE_FUSED_KDA_DECODE block in ops.h. Since KDA is restricted to SM90+, this caused compilation to fail on pre-Hopper architectures (like Ampere SM 8.6) which support GDN but not KDA. This commit moves the declaration to the correct VLLM_ENABLE_FUSED_GDN_DECODE guard. Signed-off-by: prakharP <prakharpant288@gmail.com>
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Same break on SM 8.0, so this fix covers that case too. Building at Observed at Interim workaround for anyone blocked meanwhile: Found while validating an unrelated PR on a 4×A100 box. |
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Also hits Ada / SM 8.9 — L40S, CUDA 13.0, PyTorch 2.13.0+cu130. Patch builds clean. Covers 8.0/8.6/8.9 now. |
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@mosafariuk @yafshar The fix should work on all pre 9 hardware The above archs are defined under FUSED_GDN_DECODE_ARCHS where the function is compiled but the function was declared under the wrong if def that only has the following archs - So the fix works for 8.6, 8.0, and 8.9. |
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Hitting the exact same problem trying to build from main (commit: 6feafb8) on an Ampere system. Applying the patch described here fixes the build. |
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#51674 |
I think it was just a mistake on where the |
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@cfdim No it wasn't caught since the original commit has been merged. |
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/ci run |
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Thank you for the fix!
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✅ Triggered Buildkite CI #85810 for commit |
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✅ @prakharPant, CI is now available for this PR.
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vllm-project#52743) Signed-off-by: prakharP <prakharpant288@gmail.com>
vllm-project#52743) Signed-off-by: prakharP <prakharpant288@gmail.com> Signed-off-by: khushali9 <khushali.desai9@gmail.com>
vllm-project#52743) Signed-off-by: prakharP <prakharpant288@gmail.com>
vllm-project#52743) Signed-off-by: prakharP <prakharpant288@gmail.com>
vllm-project#52743) Signed-off-by: prakharP <prakharpant288@gmail.com>
The FUSED_GDN_DECODE_ARCHS list includes 10.0f and 12.0f but omits 11.0f, so
sm_110 (Jetson Thor / DGX Spark-class Blackwell) never builds the fused GDN
decode kernel and every Gated-DeltaNet layer silently falls back to the Triton
path ("Falling back to the Triton GDN decode path:
fused_gdn_decode_post_conv_mtp is not built"). Seven other arch lists in this
file already carry 11.0f (e.g. FP4_SM100_ARCHS, MLA_ARCHS).
The ops.h declaration-guard mismatch this used to expose was fixed separately
in vllm-project#52743; with that in place, adding the arch is a one-line change.
Related: vllm-project#54084.
Signed-off-by: Adithya Kambat Shankar <adithya@zededa.com>
vllm-project#52743) Signed-off-by: prakharP <prakharpant288@gmail.com> (cherry picked from commit b2a6e9d)
vllm-project#52743) Signed-off-by: prakharP <prakharpant288@gmail.com>
7 participants
fused_gdn_decode_post_conv_mtp was mistakenly placed inside the VLLM_ENABLE_FUSED_KDA_DECODE block in ops.h. Since KDA is restricted to SM90+, this caused compilation to fail on pre-Hopper architectures (like Ampere SM 8.6) which support GDN but not KDA. This commit moves the declaration to the correct VLLM_ENABLE_FUSED_GDN_DECODE guard.
Purpose
Building vLLM from source fails on Ampere (SM 8.6) and other pre-Hopper architectures with the following error:
error: ‘fused_gdn_decode_post_conv_mtp’ was not declared in this scopeThis occurs because
fused_gdn_decode_post_conv_mtpincsrc/libtorch_stable/ops.hwas mistakenly placed inside the#ifdef VLLM_ENABLE_FUSED_KDA_DECODEpreprocessor block. Because KDA requires SM90+ (Hopper) or newer, theVLLM_ENABLE_FUSED_KDA_DECODEflag is not defined on Ampere systems. However, GDN is supported on Ampere (VLLM_ENABLE_FUSED_GDN_DECODE=1), sotorch_bindings.cppattempts to bind the GDN function, resulting in a compilation failure since the declaration is missing.Solution
Separated the declarations. Moved
fused_gdn_decode_post_conv_mtpout of the KDA block and placed it under its correct#ifdef VLLM_ENABLE_FUSED_GDN_DECODEpreprocessor guard.Test
pip install -e .successfully compiles and installs on an Ampere (SM 8.6) system without build errors.supported_models.mdandexamplesfor a new model.BEFORE SUBMITTING, PLEASE READ https://docs.vllm.ai/en/latest/contributing (anything written below this line will be removed by GitHub Actions)
co author: Gemini