Micro-optimize Object#class
#14413
Merged
Micro-optimize Object#class
#14413
+79
−7
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
Since `BUILTIN_TYPE` and `RCLASS_SINGLETON_P` are both stored in `RBasic.flags`, we can combine these two checks in a single bitmask. This rely on `T_ICLASS` and `T_CLASS` not overlapping, and assume `klass` is always either of these types. Just combining the masks brings a small but consistent 1.08x speedup on the simple case benchmark. ``` compare-ruby: ruby 3.5.0dev (2025-08-30T01:45:42Z obj-class 01a57bd) +YJIT +PRISM [arm64-darwin24] built-ruby: ruby 3.5.0dev (2025-08-30T09:56:24Z obj-class 2685f8dbb4) +YJIT +PRISM [arm64-darwin24] | |compare-ruby|built-ruby| |:----------|-----------:|---------:| |obj | 444.410| 478.895| | | -| 1.08x| |extended | 135.139| 140.206| | | -| 1.04x| |singleton | 165.155| 155.832| | | 1.06x| -| |immediate | 380.103| 432.090| | | -| 1.14x| ``` But with the RB_UNLIKELY compiler hint, it's much more significant, however the singleton and enxtended cases are slowed down. However we can assume the simple case is way more common than the other two. ``` compare-ruby: ruby 3.5.0dev (2025-08-30T01:45:42Z obj-class 01a57bd) +YJIT +PRISM [arm64-darwin24] built-ruby: ruby 3.5.0dev (2025-08-30T09:51:01Z obj-class 12d01a1b02) +YJIT +PRISM [arm64-darwin24] | |compare-ruby|built-ruby| |:----------|-----------:|---------:| |obj | 444.951| 556.191| | | -| 1.25x| |extended | 136.836| 113.871| | | 1.20x| -| |singleton | 166.335| 167.747| | | -| 1.01x| |immediate | 379.642| 509.515| | | -| 1.34x| ```
This requires ensuring T_MODULE never has FL_SINGLETON set, so RMODULE_IS_REFINEMENT had to be moved.
`Kernel#class` can't possibly be called on an hidden object, hence we don't need to check for `klass == 0`. ``` compare-ruby: ruby 3.5.0dev (2025-08-30T01:45:42Z obj-class 01a57bd) +YJIT +PRISM [arm64-darwin24] built-ruby: ruby 3.5.0dev (2025-08-30T10:21:10Z obj-class b67c16c) +YJIT +PRISM [arm64-darwin24] | |compare-ruby|built-ruby| |:----------|-----------:|---------:| |obj | 445.217| 642.446| | | -| 1.44x| |extended | 136.826| 117.974| | | 1.16x| -| |singleton | 166.269| 166.695| | | -| 1.00x| |immediate | 380.243| 515.775| | | -| 1.36x| ```
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.
Since
BUILTIN_TYPEandRCLASS_SINGLETON_Pare both stored inRBasic.flags, we can combine these two checks in a single bitmask.This rely on
T_ICLASSandT_CLASSnot overlapping, and assumeklassis always either of these types.Just combining the masks brings a small but consistent 1.08x speedup on the simple case benchmark.
But with the RB_UNLIKELY compiler hint, it's much more significant, however the singleton and enxtended cases are slowed down.
However we can assume the simple case is way more common than the other two.
And since the logic is very similar, I was able to reuse
fake_class_pinrb_class_realsimply by ensuringT_MODULEnever hasFL_SINGLETONset.Then, when we're calling from Ruby's
Kernel#classmethod, we know for sureRBasic.klasscan't possibly be0, so if we add a specialized function that skips the null check, we can speed the method some more:In a followup, It could be worth exploring the possibility of ensuring
T_ICLASSalways hadFL_SINGLETONset, as it would allow reducingfake_class_pto a single bit check. But not sure it would make much of a difference.Another thing worth exploring would be YJIT codegen.