On Wed, May 18, 2016 at 12:12:13PM -0700, Thomas Garnier wrote: > I thought the mix of slab_test & kernbench would show a diverse > picture on perf data. Is there another test that you think would be > useful? Single thread testing on slab_test would be meaningful because it also touch the slowpath. Problem is just unstable result of slab_test. You can get more stable result of slab_test if you repeat same test sometimes and get average result. Please use following slab_test. It will do each operations 100000 times and repeat it 50 times. https://github.com/JoonsooKim/linux/blob/slab_test_robust-next-20160509/mm/slab_test.c I did a quick test for this patchset and get following result. - Before (With patch and randomization is disabled by config) Single thread testing ===================== 1. Kmalloc: Repeatedly allocate then free test 100000 times kmalloc(8) -> 42 cycles kfree -> 67 cycles 100000 times kmalloc(16) -> 43 cycles kfree -> 68 cycles 100000 times kmalloc(32) -> 47 cycles kfree -> 72 cycles 100000 times kmalloc(64) -> 54 cycles kfree -> 78 cycles 100000 times kmalloc(128) -> 75 cycles kfree -> 87 cycles 100000 times kmalloc(256) -> 84 cycles kfree -> 111 cycles 100000 times kmalloc(512) -> 82 cycles kfree -> 112 cycles 100000 times kmalloc(1024) -> 86 cycles kfree -> 113 cycles 100000 times kmalloc(2048) -> 113 cycles kfree -> 127 cycles 100000 times kmalloc(4096) -> 151 cycles kfree -> 154 cycles - After (With patch and randomization is enabled by config) Single thread testing ===================== 1. Kmalloc: Repeatedly allocate then free test 100000 times kmalloc(8) -> 51 cycles kfree -> 68 cycles 100000 times kmalloc(16) -> 57 cycles kfree -> 70 cycles 100000 times kmalloc(32) -> 70 cycles kfree -> 75 cycles 100000 times kmalloc(64) -> 95 cycles kfree -> 84 cycles 100000 times kmalloc(128) -> 142 cycles kfree -> 97 cycles 100000 times kmalloc(256) -> 150 cycles kfree -> 107 cycles 100000 times kmalloc(512) -> 151 cycles kfree -> 107 cycles 100000 times kmalloc(1024) -> 154 cycles kfree -> 110 cycles 100000 times kmalloc(2048) -> 230 cycles kfree -> 124 cycles 100000 times kmalloc(4096) -> 423 cycles kfree -> 165 cycles It seems that performance decreases a lot but I don't care about it because it is a security feature and I don't have a better idea. Thanks. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>