Re: [PATCH] lib: Make _find_next_bit helper function inline
From: Cassidy Burden
Date: Wed Jul 29 2015 - 16:40:46 EST
I changed the test module to now set the entire array to all 0/1s and
only flip a few bits. There appears to be a performance benefit, but
it's only 2-3% better (if that). If the main benefit of the original
patch was to save space then inlining definitely doesn't seem worth the
small gains in real use cases.
find_next_zero_bit (us)
old new inline
14440 17080 17086
4779 5181 5069
10844 12720 12746
9642 11312 11253
3858 3818 3668
10540 12349 12307
12470 14716 14697
5403 6002 5942
2282 1820 1418
13632 16056 15998
11048 13019 13030
6025 6790 6706
13255 15586 15605
3038 2744 2539
10353 12219 12239
10498 12251 12322
14767 17452 17454
12785 15048 15052
1655 1034 691
9924 11611 11558
find_next_bit (us)
old new inline
8535 9936 9667
14666 17372 16880
2315 1799 1355
6578 9092 8806
6548 7558 7274
9448 11213 10821
3467 3497 3449
2719 3079 2911
6115 7989 7796
13582 16113 15643
4643 4946 4766
3406 3728 3536
7118 9045 8805
3174 3011 2701
13300 16780 16252
14285 16848 16330
11583 13669 13207
13063 15455 14989
12661 14955 14500
12068 14166 13790
On 7/29/2015 6:30 AM, Alexey Klimov wrote:
I will re-check on another machine. It's really interesting if
__always_inline makes things better for aarch64 and worse for x86_64. It
will be nice if someone will check it on x86_64 too.
Very odd, this may be related to the other compiler optimizations Yuri
mentioned?
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