Hi,
This is rework of the following discussed patch.
https://lore.kernel.org/all/20230613043308.GA1027@KORCO045595.samsungds.net/
Changes from the previous patch
- Split to revert and modify patches
- Change according to Waiman Long's review
More wording to documentation part
Change module_param to early_param
Code change by Waiman Long's suggestion
In mobile environment, reader optimistic spinning is still useful
because there're not many readers. In my test result at android device,
it improves application startup time about 3.8%
App startup time is most important factor for android user expriences.
So, re-enable reader optimistic spinning by this commit. And,
make it optional feature by cmdline.
Test result:
This is 15 application startup performance in our exynos soc.
- Cortex A78*2 + Cortex A55*6
- unit: ms (lower is better)
Application base opt_rspin Diff Diff(%)
-------------------- ------ --------- ---- -------
* Total(geomean) 343 330 -13 +3.8%
-------------------- ------ --------- ---- -------
helloworld 110 108 -2 +1.8%
Amazon_Seller 397 388 -9 +2.3%
Whatsapp 311 304 -7 +2.3%
Simple_PDF_Reader 500 463 -37 +7.4%
FaceApp 330 317 -13 +3.9%
Timestamp_Camera_Free 451 443 -8 +1.8%
Kindle 629 597 -32 +5.1%
Coinbase 243 233 -10 +4.1%
Firefox 425 399 -26 +6.1%
Candy_Crush_Soda 552 538 -14 +2.5%
Hill_Climb_Racing 245 230 -15 +6.1%
Call_Recorder 437 426 -11 +2.5%
Color_Fill_3D 190 180 -10 +5.3%
eToro 512 505 -7 +1.4%
GroupMe 281 266 -15 +5.3%
Bongkyu Kim (2):
Revert "locking/rwsem: Remove reader optimistic spinning"
locking/rwsem: Make reader optimistic spinning optional
.../admin-guide/kernel-parameters.txt | 9 +
kernel/locking/lock_events_list.h | 5 +-
kernel/locking/rwsem.c | 299 +++++++++++++++---
3 files changed, 265 insertions(+), 48 deletions(-)
--
2.36.1