Fix performance regression after OPTNONE changes #646
Merged
Conversation
This file contains 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
The OPTNONE changes in DLTcollab#638 introduced 25% performance regression in Cycles render engine running on Apple Silicon: https://projects.blender.org/blender/blender/issues/126408 The reason for this is because as per Clang documentation optnone is incompatible with inline, so none of the functions that is marked as optnone is inlined. The biggest bottleneck for Cycles after that change is _mm_mul_ps. This change makes it so _mm_mul_ps is inlined and is no longer marked as optnone. This solves the immediate performance regression, and the correctness is verified using the sse2neon's test suit on M2 Ultra and M3 Max, with various optimization levels (default, -O2, -O3). Additionally, adding -Wstrict-aliasing flag does not introduce new warnings.
|
Thank @sergeyvfx for contributing! |
hubot
pushed a commit
to blender/blender
that referenced
this pull request
Aug 16, 2024
The previous update introduced a regression #126408 This update pulls a fix committed to the upstream: DLTcollab/sse2neon#646 Pull Request: https://projects.blender.org/blender/blender/pulls/126413
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
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Outdated suggestions cannot be applied.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.
The OPTNONE changes in #638 introduced 25% performance regression in Cycles render engine running on Apple Silicon:
https://projects.blender.org/blender/blender/issues/126408
The reason for this is because as per Clang documentation optnone is incompatible with inline, so none of the functions that is marked as optnone is inlined. The biggest bottleneck for Cycles after that change is _mm_mul_ps.
This change makes it so _mm_mul_ps is inlined and is no longer marked as optnone. This solves the immediate performance regression, and the correctness is verified using the sse2neon's test suit on M2 Ultra and M3 Max, with various optimization levels (default, -O2, -O3).
Additionally, adding -Wstrict-aliasing flag does not introduce new warnings.