linux-kernel - [PATCH v1 0/2] Make reader optimistic spinning optional

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <20230831030004.16576-1-bongkyu7.kim@samsung.com>
Date:   Thu, 31 Aug 2023 12:00:02 +0900
From:   Bongkyu Kim <bongkyu7.kim@...sung.com>
To:     peterz@...radead.org, mingo@...hat.com, will@...nel.org,
        longman@...hat.com, boqun.feng@...il.com
Cc:     linux-kernel@...r.kernel.org, gregkh@...uxfoundation.org,
        bongkyu7.kim@...sung.com
Subject: [PATCH v1 0/2] Make reader optimistic spinning optional

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