linux-kernel - [PATCH v5 0/2] bitops: Optimize fns() for improved performance

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: <20240502092443.6845-1-visitorckw@gmail.com>
Date: Thu,  2 May 2024 17:24:41 +0800
From: Kuan-Wei Chiu <visitorckw@...il.com>
To: akpm@...ux-foundation.org,
	yury.norov@...il.com
Cc: linux@...musvillemoes.dk,
	n26122115@...ncku.edu.tw,
	jserv@...s.ncku.edu.tw,
	linux-kernel@...r.kernel.org,
	Kuan-Wei Chiu <visitorckw@...il.com>
Subject: [PATCH v5 0/2] bitops: Optimize fns() for improved performance

Hello,

This patch series optimizes the fns() function by avoiding repeated
calls to __ffs(). Additionally, tests for fns() have been added in
lib/test_bitops.c.

Changes in v5:
- Reduce testing iterations from 1000000 to 10000 to decrease testing
  time.
- Move 'buf' inside the function.
- Mark 'buf' as __initdata.
- Assign the results of fns() to a volatile variable to prevent
  compiler optimization.
- Remove the iteration count from the benchmark result.
- Update benchmark results in the commit message.

Changes in v4:
- Correct get_random_long() -> get_random_bytes() in the commit
  message.

Changes in v3:
- Move the benchmark test for fns() to lib/test_bitops.c.
- Exclude the overhead of random number generation from the benchmark
  result.
- Change the output to print only a total gross instead of each n in
  the benchmark result.
- Update the commit message in the second patch.

Changes in v2:
- Add benchmark test for fns() in lib/find_bit_benchmark.c.
- Change the loop in fns() by counting down from n to 0.
- Add find_bit benchmark result for find_nth_bit in commit message.

Link to v4: https://lkml.kernel.org/20240501132047.14536-1-visitorckw@gmail.com
Link to v3: https://lkml.kernel.org/20240501071647.10228-1-visitorckw@gmail.com
Link to v2: https://lkml.kernel.org/20240430054912.124237-1-visitorckw@gmail.com
Link to v1: https://lkml.kernel.org/20240426035152.956702-1-visitorckw@gmail.com

Kuan-Wei Chiu (2):
  lib/test_bitops: Add benchmark test for fns()
  bitops: Optimize fns() for improved performance

 include/linux/bitops.h | 12 +++---------
 lib/test_bitops.c      | 22 ++++++++++++++++++++++
 2 files changed, 25 insertions(+), 9 deletions(-)

-- 
2.34.1