On Fri, Apr 08, 2016 at 07:20:54AM +0200, Mike Galbraith wrote: > Greetings, > > While measuring current NO_HZ cost to light tasks jabbering cross core > at high frequency (~7% max), I noticed that master lost an improvement > for same acquired in 4.5, so bisected it. > > 4.5.0 > homer:~ # taskset 0xc pipe-test 1 > 2.367681 usecs/loop -- avg 2.367681 844.7 KHz > 2.372502 usecs/loop -- avg 2.368163 844.5 KHz > 2.342506 usecs/loop -- avg 2.365597 845.5 KHz > 2.383029 usecs/loop -- avg 2.367341 844.8 KHz > 2.321859 usecs/loop -- avg 2.362792 846.5 KHz 1.00 > > master > homer:~ # taskset 0xc pipe-test 1 > 2.797656 usecs/loop -- avg 2.797656 714.9 KHz > 2.804518 usecs/loop -- avg 2.798342 714.7 KHz > 2.804206 usecs/loop -- avg 2.798929 714.6 KHz > 2.802887 usecs/loop -- avg 2.799324 714.5 KHz > 2.801577 usecs/loop -- avg 2.799550 714.4 KHz 0.84 > > master 0c313cb20732 reverted > homer:~ # !taskset > homer:~ # taskset 0xc pipe-test 1 > 2.277494 usecs/loop -- avg 2.277494 878.2 KHz > 2.320979 usecs/loop -- avg 2.281843 876.5 KHz > 2.272750 usecs/loop -- avg 2.280933 876.8 KHz > 2.272209 usecs/loop -- avg 2.280061 877.2 KHz > 2.277279 usecs/loop -- avg 2.279783 877.3 KHz 1.03 > > 0c313cb207326f759a58f486214288411b25d4cf is the first bad commit > commit 0c313cb207326f759a58f486214288411b25d4cf > Author: Rafael J. Wysocki <rafael.j.wyso...@intel.com> > Date: Sun Mar 20 01:33:35 2016 +0100 > > cpuidle: menu: Fall back to polling if next timer event is near >
Cute, I thought you used governor=performance for your runs?
