perf(iobufpool): optimize pool index calculations with O(1) bit manipulation #2432
+23
−15
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
…ulation Replace O(n) loops in getPoolIdx and putPoolIdx with O(1) direct calculation using bits.Len and bits.TrailingZeros. Pool sizes are powers of 2, so we can derive indices directly from buffer size/capacity exponents. getPoolIdx: Use bits.Len to calculate ceil(log2(size)) in constant time putPoolIdx: Use bits.TrailingZeros to calculate log2(cap) in constant time Benchmarks (Apple M1 Pro): getPoolIdx: 16.97ns → 3.52ns (4.8x faster) putPoolIdx: 24.75ns → 4.16ns (5.9x faster) Get/Put cycle: 89.15ns → 76.57ns (14% faster) Get(32K): 15.38ns → 10.52ns (32% faster) Signed-off-by: Mathias Bogaert <mathias.bogaert@gmail.com>
Contributor
Author
|
Failing CI doesn't seem related? |
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Outdated suggestions cannot be applied.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.
Replace O(n) loops in getPoolIdx and putPoolIdx with O(1) direct calculation using bits.Len and bits.TrailingZeros. Pool sizes are powers of 2, so we can derive indices directly from buffer size/capacity exponents.
getPoolIdx: Use bits.Len to calculate ceil(log2(size)) in constant time
putPoolIdx: Use bits.TrailingZeros to calculate log2(cap) in constant time
Benchmarks (Apple M1 Pro):