common/buffer: replace RWLock with spinlocks #7294
Merged
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Outdated suggestions cannot be applied.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.
This decreases buffer::raw size by about 100 bytes (since RWLock occupies
104 bytes and simple_spinlock_t just 4) and also decreases time wasted
by locking and unlocking, possibly reducing context switches too.
Particularly visible with small I/O block size.
For example, putting a 4GB file in 4KB blocks is faster by around 4%:
Before:
After:
Also, memory usage decreases. Following code:
causes to consume 6.3GB of RAM before applying this patch and 3.6GB after.
Signed-off-by: Piotr Dałek piotr.dalek@ts.fujitsu.com