> > >-----Original Message----- >From: Daniel Vetter [mailto:daniel.vetter@xxxxxxxx] On Behalf Of Daniel Vetter >Sent: Thursday, December 10, 2015 12:53 PM >To: Morton, Derek J >Cc: Daniel Vetter; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Wood, Thomas >Subject: Re: [PATCH i-g-t] gem_flink_race/prime_self_import: Improve test reliability > >On Thu, Dec 10, 2015 at 11:51:29AM +0000, Morton, Derek J wrote: >> > >> > >> >-----Original Message----- >> >From: Daniel Vetter [mailto:daniel.vetter@xxxxxxxx] On Behalf Of >> >Daniel Vetter >> >Sent: Thursday, December 10, 2015 10:13 AM >> >To: Morton, Derek J >> >Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx; Wood, Thomas >> >Subject: Re: [PATCH i-g-t] >> >gem_flink_race/prime_self_import: Improve test reliability >> > >> >On Tue, Dec 08, 2015 at 12:44:44PM +0000, Derek Morton wrote: >> >> gem_flink_race and prime_self_import have subtests which read the >> >> number of open gem objects from debugfs to determine if objects >> >> have leaked during the test. However the test can fail sporadically >> >> if the number of gem objects changes due to other process activity. >> >> This patch introduces a change to check the number of gem objects >> >> several times to filter out any fluctuations. >> > >> >Why exactly does this happen? IGT tests should be run on bare metal, >> >with everything else killed/subdued/shutup. If there's still things >> >going on that create objects, we need to stop them from doing that. >> > >> >If this only applies to Android, or some special Android deamon them >> >imo check for that at runtime and igt_skip("your setup is invalid, >> >deamon %s running\n"); is the correct fix. After all just because you >> >sampled for a bit doesn't mean that it wont still change right when >> >you start running the test for real, so this is still fragile. >> >> Before running tests on android we do stop everything possible. I >> suspect the culprit is coreu getting automatically restarted after it >> is stopped. I had additional debug while developing this patch and >> what I saw was the system being mostly quiescent but with some very >> low level background activity. 1 extra object being created and then >> deleted occasionally. Depending on whether it occurred at the start or >> end of the test it was resulting in a reported leak of either 1 or -1 objects. >> The patch fixes that issue by taking several samples and requiring >> them to be the same, therefore filtering out the low level background noise. >> It would not help if something in the background allocated an object >> and kept it allocated, but I have not seen that happen. I only saw >> once the object count increasing for 2 consecutive reads hence the >> count to 4 to give a margin. The test was failing about 10%. With this >> patch I got 100% pass across 300 runs of each of the tests. > >Hm, piglit checks that there's no other drm clients running. Have you tried re-running that check to zero in on the culprit? We don't use piglet to run IGT tests on Android. I have had a look at what piglet does and added the same check to our scripts. (It reads a list of clients from /sys/kernel/debug/dri/0/clients) For CHV it shows a process called 'y', though that seems to be some issue on CHV that all driver clients are called 'y'. I checked on BXT which properly shows the process names and it looks like it is the binder process (which is handling some inter process communication). I don't think this is something we can stop. > >> If you are concerned about the behaviour when running the test with a >> load of background activity I could add code to limit to the reset of >> the count and fail the test in that instance. That would give a >> benefit of distinguishing a test fail due to excessive background >> activity from a detected leak. > >I'm also concerned for the overhead this causes everyone else. If this really is some Android trouble then I think it'd be good to only compile this on Android. But would still be much better if you can get to a reliably clean test environment. I will make the loop part android specific. //Derek > >> I would not want to just have the test skip as that introduces a hole >> in our test coverage. >> >> >Also would be good to extract get_stable_obj_count to a proper igt >> >library function, if it indeed needs to be this tricky. And then add >> >the explanation for why we need this in the gtkdoc. >> >> I can move the code to an igt library. Which library would you suggest? Igt_debugfs ? > >Hm yeah, it's a bit the dumping ground for all things debugfs access ;-) -Daniel >-- >Daniel Vetter >Software Engineer, Intel Corporation >http://blog.ffwll.ch > _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
