Atomic operations on Pointers #37683
Closed
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
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 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Outdated suggestions cannot be applied.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.
For some reason,
Threadsdoesn't support atomic operations through general pointers. However, we need these operations in order to e.g. atomically operate on array entries.While doing that, I noticed that llvm supports perfectly fine
atomicrmw faddandfsubintrinsics. These also boil down to acasloop on x86_64, but the emitted assembly looks nicer for the llvm intrinsic than for the julia loop, so I took the liberty to change that as well (I don't expect significant performance changes for that).Ref https://discourse.julialang.org/t/scattered-atomic-writes-into-array/46990/ and #32455