forked from projectceladon/linux-intel-lts2021
-
Notifications
You must be signed in to change notification settings - Fork 0
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Revert "block/mq-deadline: Prioritize high-priority requests"
This reverts commit fb92603. Zhen reports that this commit slows down mq-deadline on a 128 thread box, going from 258K IOPS to 170-180K. My testing shows that Optane gen2 IOPS goes from 2.3M IOPS to 1.2M IOPS on a 64 thread box. Looking in detail at the code, the main culprit here is needing to sum percpu counters in the dispatch hot path, leading to very high CPU utilization there. To make matters worse, the code currently needs to sum 2 percpu counters, and it does so in the most naive way of iterating possible CPUs _twice_. Since we're close to release, revert this commit and we can re-do it with regular per-priority counters instead for the 5.15 kernel. Link: https://lore.kernel.org/linux-block/20210826144039.2143-1-thunder.leizhen@huawei.com/ Reported-by: Zhen Lei <thunder.leizhen@huawei.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
- Loading branch information
Showing
1 changed file
with
5 additions
and
37 deletions.
There are no files selected for viewing
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