On 2017-06-19 13:31:28 [+0200], Mike Galbraith wrote: > > > Scratch that "appears", changing it to TASK_NORMAL just fixed my DL980 > > > running otherwise absolutely pristine 4.9-rt21, after having double > > > verified that rt20 works fine. Now to go back to 4.11/master/tip-rt, > > > make sure that the little bugger really really REALLY ain't fscking > > > with me for the sheer fun of it, futexes being made of pure evil :) > > > > So v4.9-rt20 works fine but -rt21 starts to lose wakeups on DL980 in > > general or just with "futex_wait -n 4" ? > > -rt20 is verified to work fine, -rt21 starts hanging with futextest. > The futex_wait -n 4 testcase was distilled out of seeing the full > futextest/run.sh hanging. The only symptom I've _seen_ on the DL980 is > futextest hanging. On the desktop, I've seen more, and may still, I'll > know when I see or don't see desktop gizmos occasionally go comatose. rt20…rt21 is just https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/tree/patches/sched-Prevent-task-state-corruption-by-spurious-lock.patch?h=linux-4.9.y-rt-patches Let me verify that here and fire maybe the four socket box. > > > My testcase is to run futex_wait -n 4 in a modest sized loop. Odd > > > thing is that it only reproduces on the DL980 if I let it use multiple > > > sockets, pin it to one, and all is peachy, (rather seems to be given) > > > whereas on desktop box, the hang is far more intermittent, but there. > > > > do I parse it right, as v4.9-rt21 (without the change above) works with > > the testcase mentioned if you pin it to one socket but does not work if > > you let it use multiple sockets. > > And your desktop box hangs no matter what? > > No no, desktop box will reproduce, but not nearly as reliably as the 8 > socket box does, but yes, it seems to work fine on the DL980 when > pinned to one socket. I was testing 4.9-rt because hunt was in > progress when 4.11-rt was born. Let me try futex-wait test on more boxes then… > -Mike Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
