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| author | Kemi Wang <[email protected]> | 2017-10-24 01:16:42 +0000 |
|---|---|---|
| committer | Jens Axboe <[email protected]> | 2018-02-02 14:56:30 +0000 |
| commit | 60f91826ca62bcf85d6d5fc90941337282787671 (patch) | |
| tree | 99c751953bbeb84e3afb40338db1d3df30b90be6 /scripts/gcc-plugins/cyc_complexity_plugin.c | |
| parent | blk-mq-sched: Enable merging discard bio into request (diff) | |
| download | kernel-60f91826ca62bcf85d6d5fc90941337282787671.tar.gz kernel-60f91826ca62bcf85d6d5fc90941337282787671.zip | |
buffer: Avoid setting buffer bits that are already set
It's expensive to set buffer flags that are already set, because that
causes a costly cache line transition.
A common case is setting the "verified" flag during ext4 writes.
This patch checks for the flag being set first.
With the AIM7/creat-clo benchmark testing on a 48G ramdisk based-on ext4
file system, we see 3.3%(15431->15936) improvement of aim7.jobs-per-min on
a 2-sockets broadwell platform.
What the benchmark does is: it forks 3000 processes, and each process do
the following:
a) open a new file
b) close the file
c) delete the file
until loop=100*1000 times.
The original patch is contributed by Andi Kleen.
Signed-off-by: Andi Kleen <[email protected]>
Tested-by: Kemi Wang <[email protected]>
Signed-off-by: Kemi Wang <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
Diffstat (limited to 'scripts/gcc-plugins/cyc_complexity_plugin.c')
0 files changed, 0 insertions, 0 deletions