Add pathfinder support for cupti64_2026.1.2.dll (CTK 13.2.2) by zklaus · Pull Request #3279 · NVIDIA/cuda-python

zklaus · 2026-10-29T13:17:12Z

Description

nvidia-cuda-cupti 13.2.86 (CUDA 13.2.2) ships cupti64_2026.1.2.dll on Windows, which the cupti descriptor does not list, so load_nvidia_dynamic_lib("cupti") fails on a machine that only has the 13.2 wheels installed.

Found via the PyTorch cu132 Windows nightly, which loads the CUDA wheel libraries through cuda-pathfinder at import time (pytorch/pytorch#202206).

Checklist

I have read the Contributing Guidelines.
~~New or existing tests cover these changes.~~
The documentation is up to date with these changes.

nvidia-cuda-cupti 13.2.86 (CUDA 13.2.2) ships cupti64_2026.1.2.dll on Windows, which the cupti descriptor does not list, so load_nvidia_dynamic_lib("cupti") fails on a machine that only has the 13.2 wheels installed. Found via the PyTorch cu132 Windows nightly, which loads the CUDA wheel libraries through cuda-pathfinder at import time (pytorch/pytorch#202206). Signed-off-by: Klaus Zimmermann <klaus.zimmermann@quansight.com>

copy-pr-bot · 2026-10-29T13:17:17Z

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coderabbitai · 2026-10-29T13:21:29Z

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Reviewing files that changed from the base of the PR and between 916198a and ed8b385.

Files selected for processing: 2

cuda_pathfinder/docs/nv-versions.json
cuda_pathfinder/docs/source/release/1.8.5-notes.rst

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📝 Summary

Summary by CodeRabbit

Bug Fixes
- Improved Windows compatibility for applications using CUDA profiling tools. The library lookup now recognizes cupti64_2026.1.2.dll among the preferred versions, helping applications locate the matching library when needed.
Documentation
- Added release notes and a documentation listing for version 1.8.5, including details about support for this Windows CUPTI library.

The Windows CUPTI DLL preference list now includes cupti64_2026.1.2.dll. The documentation adds CUDA PathFinder version 1.8.5 and release notes for this DLL.

Changes: CUPTI DLL candidates

Layer / File(s)	Summary
Windows DLL candidate list `cuda_pathfinder/cuda/pathfinder/_dynamic_libs/descriptor_catalog.py`, `cuda_pathfinder/docs/nv-versions.json`, `cuda_pathfinder/docs/source/release/1.8.5-notes.rst`	The CUPTI Windows DLL preference list adds `cupti64_2026.1.2.dll` between the 2026.2.0 and 2026.1.1 entries. The version list adds 1.8.5, and the release notes describe the DLL addition.

Possibly related issues

[BUG]: Windows CTK 13.2.2 CUPTI Name Unsupported #3281: Reports that load_nvidia_dynamic_lib cannot load cupti64_2026.1.2.dll because the descriptor lacks its name. This change adds that DLL name.

Possibly related PRs

NVIDIA/cuda-python#3233: Adds lookup APIs that use the descriptor catalog, which now includes the new DLL candidate.

Suggested labels: enhancement

Suggested reviewers: rwgk

Priority: Normal

Change: Feature

Merge Risk: Minimal · up to ed8b3

No actionable merge risk remains.

- [ ] Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

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rparolin · 2026-10-29T14:15:12Z

            "cupti64_2026.3.0.dll",
            "cupti64_2026.2.1.dll",
            "cupti64_2026.2.0.dll",
+            "cupti64_2026.1.2.dll",


Please add cupti discovery unit tests to the prei-existing set. Thank you.

We have that, but this particular version escaped our testing:
In theory, we'd have to test against all released CTK version, every major.minor release.
Currently we're only testing against the latest major.minor releases.

It's a complex project to ensure full coverage at a reasonable cost (runner time).

This issue will be fixed with the next CTK release onwards. Windows Cupti will follow the same naming convention as linux

rwgk · 2026-10-29T14:33:21Z

            "cupti64_2026.3.0.dll",
            "cupti64_2026.2.1.dll",
            "cupti64_2026.2.0.dll",
+            "cupti64_2026.1.2.dll",


We have that, but this particular version escaped our testing:
In theory, we'd have to test against all released CTK version, every major.minor release.
Currently we're only testing against the latest major.minor releases.

It's a complex project to ensure full coverage at a reasonable cost (runner time).

Signed-off-by: Ralf W. Grosse-Kunstleve <rgrossekunst@nvidia.com>

rwgk · 2026-10-29T15:59:05Z

I just pushed pathfinder 1.8.5 release notes, so that we can make a pathfinder release immediately after this PR merges.

rwgk · 2026-10-29T16:04:54Z

/ok to test ed8b385

rwgk · 2026-10-29T16:06:49Z

I set this PR to auto-merge. I'll keep an eye on it and will start the release after the PR has merged. End-to-end it'll probably take 3-4 hours to get the release out (2 x full CI is the bottleneck).

github-actions · 2026-10-29T16:21:35Z

Doc Preview CI
Preview removed because the pull request was closed or merged.

Removed preview folders for the following PRs: - PR #2494 - PR #3186 - PR #3259 - PR #3274 - PR #3275 - PR #3279

Please open this PR as a draft and mark it ready for review once the description and code are ready to be looked at. Before submitting, please review: - [PR lifecycle](https://github.com/pytorch/pytorch/blob/main/CONTRIBUTING.md#pr-lifecycle) in the contributing guide - [AI-Assisted Development](https://github.com/pytorch/pytorch/blob/main/AI_POLICY.md) policy Go through the following checklist - [x] Passes lint (`spin fixlint`) - [ ] Added/updated tests - [ ] Updated documentation (if applicable) - [ ] Included benchmark results (for PRs impacting perf) ---  ## Linked issue or supporting maintainer  Fixes #202565 ## BC-breaking? No ## Summary (human written only) Implements approach 1 from #202565 - Add try/except for every `load_nvidia_dynamic_lib(lib)` call - Pin cuda-pathfinder to 1.8.5 for this fix NVIDIA/cuda-python#3279 ## Agent details (if applicable)  Pull Request resolved: #202589 Approved by: https://github.com/zklaus, https://github.com/atalman

github-actions Bot added the cuda.pathfinder Everything related to the cuda.pathfinder module label Oct 29, 2026

zklaus mentioned this pull request Oct 29, 2026

[Windows] Drop the torch/lib DLL preload glob pytorch/pytorch#202206

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rparolin requested a review from rwgk October 29, 2026 14:11

rparolin reviewed Oct 29, 2026

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rparolin requested changes Oct 29, 2026

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rwgk assigned zklaus Oct 29, 2026

rwgk added this to the cuda.pathfinder next milestone Oct 29, 2026

rwgk added the P0 High priority - Must do! label Oct 29, 2026

leofang linked an issue Oct 29, 2026 that may be closed by this pull request

[BUG]: Windows CTK 13.2.2 CUPTI Name Unsupported #3281

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rparolin approved these changes Oct 29, 2026

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zklaus and others added 2 commits October 29, 2026 16:51

Merge branch 'main' into cupti-2026.1.2

916198a

docs(pathfinder): prepare 1.8.5 release notes

ed8b385

Signed-off-by: Ralf W. Grosse-Kunstleve <rgrossekunst@nvidia.com>

rwgk enabled auto-merge (squash) October 29, 2026 16:05

rwgk merged commit ecaba92 into NVIDIA:main Oct 29, 2026
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github-actions Bot pushed a commit that referenced this pull request Oct 29, 2026

Clean up PR preview folders for 6 closed/merged PRs

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Removed preview folders for the following PRs: - PR #2494 - PR #3186 - PR #3259 - PR #3274 - PR #3275 - PR #3279

akarale-nv mentioned this pull request Nov 2, 2026

[Windows] Check DLL load exception per CUDA component pytorch/pytorch#202589

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Add pathfinder support for cupti64_2026.1.2.dll (CTK 13.2.2) - #3279

Add pathfinder support for cupti64_2026.1.2.dll (CTK 13.2.2)#3279
rwgk merged 3 commits into
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zklaus:cupti-2026.1.2

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