答复: [PATCH v4 0/2] Improve the performance of bitmap_find_next_zero_area_off()

[孙毅 (Yi Sun)]

Hi Yury,

Just a gentle ping.
Is there anything I can do?

> -----邮件原件-----
> 发件人: 孙毅 (Yi Sun) <Yi.Sun@xxxxxxxxxx>
> 发送时间: 2026年6月1日 17:43
> 收件人: ynorov@xxxxxxxxxx; yury.norov@xxxxxxxxx
> 抄送: 孙毅 (Yi Sun) <Yi.Sun@xxxxxxxxxx>; mnazarewicz@xxxxxxxxx;
> akpm@xxxxxxxxxxxxxxxxxxxx; mina86@xxxxxxxxxx; akinobu.mita@xxxxxxxxx;
> linux-kernel@xxxxxxxxxxxxxxx
> 主题: [PATCH v4 0/2] Improve the performance of
> bitmap_find_next_zero_area_off()
> 
> Test code has been added to PATCH v2.
> No new APIs were introduced.
> 
> Testing with the test code showed a performance improvement
> of approximately 70%.
> 
> Test result(random):
> 	orig_ns		orig_cnt	orig_average	new_ns
> 	new_cnt		new_average	ratio
> test1	1388885		1154		1203		462923
> 	1308		353		70.7%
> test2	1393616		1324		1052		736193
> 	1212		607		42.3%
> test3	1391693		1216		1144		735808
> 	1260		583		49%
> test4	1393231		1275		1092		742731
> 	1402		529		51.6%
> test5	1390731		1260		1103		737231
> 	1274		578		47.6%
> 
> Test result(sparse):
> 	orig_ns		orig_cnt	orig_average	new_ns
> 	new_cnt		new_average	ratio
> test1	4496077		322477		13		2419462
> 	322480		7		46.2%
> test2	7514731		322482		23		5785808
> 	322476		17		26.1%
> test3	7490692		322493		23		7654423
> 	322483		23		0%
> test4	7474500		322469		23		7628230
> 	322483		23		0%
> test5	7452692		322481		23		7663116
> 	322478		23		0%
> 
> Test result explanation:
> Test both random and sparse five times.
> @orig_ns/cnt: Original version results.
> @new_ns/cnt: Optimized test results.
> @orig_average = orig_ns / orig_cnt
> @new_average = new_ns / new_cnt
> @ratio = (orig_average - new_average) / orig_average
> 
> The test results show that the optimized version
> improved performance in almost every test.
> 
> ---
> v3: https://lore.kernel.org/all/20260514090607.231387-1-yi.sun@xxxxxxxxxx
> - Based on Michał Nazarewicz's suggestion,
> code optimization was performed on PATCH v1.
> 
> v2: https://lore.kernel.org/all/20260514035644.4118050-1-yi.sun@xxxxxxxxxx
> - Do not introduce find_last_bit_from().
> 
> v1: https://lore.kernel.org/all/20260512040659.2992142-1-yi.sun@xxxxxxxxxx
> 
> 
> Yi Sun (2):
>   lib: bitmap: reduce the number of goto again in
>     bitmap_find_next_zero_area_off()
>   lib/bitmap: add tests for bitmap_find_next_zero_area_off()
> 
>  lib/bitmap.c             | 10 +++++++---
>  lib/find_bit_benchmark.c | 17 +++++++++++++++++
>  lib/test_bitmap.c        | 28 ++++++++++++++++++++++++++++
>  3 files changed, 52 insertions(+), 3 deletions(-)
> 
> --
> 2.34.1