Add regression test for get_root_mesh with multiple independent meshes #164731
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
🔗 Helpful Links🧪 See artifacts and rendered test results at hud.pytorch.org/pr/164731
Note: Links to docs will display an error until the docs builds have been completed. ✅ No FailuresAs of commit a7842e8 with merge base 660e369 ( This comment was automatically generated by Dr. CI and updates every 15 minutes. |
pytorch-bot
bot
added
oncall: distributed
fduwjj
approved these changes
Oct 6, 2025
Contributor
fduwjj
left a comment
fduwjj
left a comment
There was a problem hiding this comment.
lgtm, can you move this test after this test test_get_root_mesh? That way all get_root_mesh tests are grouped together? Thanks
Contributor
|
@pytorchbot merge |
Collaborator
Merge startedYour change will be merged once all checks pass (ETA 0-4 Hours). Learn more about merging in the wiki. Questions? Feedback? Please reach out to the PyTorch DevX Team |
Chao1Han
pushed a commit
to Chao1Han/pytorch
that referenced
this pull request
Oct 21, 2025
pytorch#164731) Fixes pytorch#163330 I tried to reproduce the bug with my 4-GPU setup (the original issue used 8 GPUs). I created several different test scenarios, trying to trigger the bug by: - creating two different device meshes - slicing them in various ways - checking if get_root_mesh() would get confused but the bug didn't show up! Everything worked correctly in `2.10`. I found that there was a massive refactoring of the `DeviceMesh` code (PR pytorch#163213) that landed on October 2nd. That PR completely rewrote how `DeviceMesh` tracks relationships between parent meshes and submeshes using. It seems like this refactoring fixed the bug! But I added a regression test to make sure it doesn't come back. The test (`test_get_root_mesh_multiple_independent_meshes`) does exactly what the bug report described: - creates two independent meshes - slices them both - verifies that each submesh correctly points back to its real parent - makes sure submeshes from mesh1 don't incorrectly claim mesh2 as their parent Pull Request resolved: pytorch#164731 Approved by: https://github.com/fduwjj
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
5 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Fixes #163330
I tried to reproduce the bug with my 4-GPU setup (the original issue used 8 GPUs). I created several different test scenarios, trying to trigger the bug by:
but the bug didn't show up! Everything worked correctly in
2.10. I found that there was a massive refactoring of theDeviceMeshcode (PR #163213) that landed on October 2nd. That PR completely rewrote howDeviceMeshtracks relationships between parent meshes and submeshes using. It seems like this refactoring fixed the bug! But I added a regression test to make sure it doesn't come back. The test (test_get_root_mesh_multiple_independent_meshes) does exactly what the bug report described:cc: @ezyang @zhiqi-0
cc @H-Huang @awgu @wanchaol @fegin @fduwjj @wz337 @wconstab @d4l3k @pragupta @msaroufim @dcci