On Fri, Nov 06, 2020 at 11:54:47AM +0100, Sebastian Andrzej Siewior wrote: > > rpi3 signaltest 5.9.0-rc8-rt12 > > 813 0_signaltest t0-max-latency : fail 214.00 > > rpi3 signaltest 5.9.0-rc8-rt12 > > 874 0_signaltest t0-max-latency : fail 217.00 > > rpi3 signaltest 5.9.0-rt16 > > 963 0_signaltest t0-max-latency : fail 321.00 > > Here, rt 13,14,15 would be interesting so we could narrow down the > ~100us. > v5.9-rc8-rt14 got new migrate-disable but I wouldn't expect it to cause > it. The other changes look also harmless (like the rtmutex redo which > should be a 0 change but then it mighe behave differently in regard to > workqueue in some corner cases). rpi3 signaltest 5.9.0-rc8-rt13 1196 0_signaltest t0-max-latency : fail 207.00 1196 0_signaltest t0-avg-latency : pass 46.00 1196 0_signaltest t0-min-latency : pass 22.00 rpi3 signaltest 5.9.0-rc8-rt14 1197 0_signaltest t0-max-latency : fail 301.00 1197 0_signaltest t0-avg-latency : pass 47.00 1197 0_signaltest t0-min-latency : pass 20.00 rpi3 signaltest 5.9.0-rt15 1198 0_signaltest t0-max-latency : fail 323.00 1198 0_signaltest t0-avg-latency : pass 47.00 1198 0_signaltest t0-min-latency : pass 21.00 > > rpi3 signaltest 5.9.1-rt19 > > 1038 0_signaltest t0-max-latency : fail 341.00 > > rpi3 signaltest 5.9.1-rt20 > > 1079 0_signaltest t0-max-latency : fail 318.00 > > So I have nothing to explain 20us improvement. I think 20us is in the range of the standard deviation for this test. So I don't think you should be concerned too much about it as long I don't have proper statistical numbers. One thing I also see is that the average was pretty constant at 47us for 5.9-rt and for 5.10-rt series it's around 55us. So something makes the whole operation slightly more expensive. > > rpi3 signaltest 5.10.0-rc1-rt1 > > 1118 0_signaltest t0-max-latency : fail 415.00 > > rpi3 signaltest 5.10.0-rc2-rt4 > > 1163 0_signaltest t0-max-latency : fail 340.00 > > -rt2 gained new kmap code. > -rt3 received an update of the above rpi3 signaltest 5.10.0-rc1-rt2 1199 0_signaltest t0-max-latency : fail 399.00 1199 0_signaltest t0-avg-latency : pass 55.00 1199 0_signaltest t0-min-latency : pass 25.00 rpi3 signaltest 5.10.0-rc2-rt3 1200 0_signaltest t0-max-latency : fail 420.00 1200 0_signaltest t0-avg-latency : pass 55.00 1200 0_signaltest t0-min-latency : pass 25.00 > But all this is only signal right? Correct. I've observed this only for signaltest and sigwaittest. > Nothing on the cyclictest front? Correct, cyclictest doesn't show any regression. > If lazy-preempt broke in a way then it should be only noticed by > cyclictest. You can however disable lazy-preempt just to be sure. Sure, will do a full run on Monday.
