On 25 August 2017 at 08:37, Luca Abeni <[email protected]> wrote: > Hi Mathieu, > > On Wed, 23 Aug 2017 13:47:13 -0600 > Mathieu Poirier <[email protected]> wrote: > >> On 22 August 2017 at 06:21, Luca Abeni <[email protected]> wrote: >> > Hi Mathieu, >> >> Good day to you, >> >> > >> > On Wed, 16 Aug 2017 15:20:36 -0600 >> > Mathieu Poirier <[email protected]> wrote: >> > >> >> This is a renewed attempt at fixing a problem reported by Steve Rostedt >> >> [1] >> >> where DL bandwidth accounting is not recomputed after CPUset and >> >> CPUhotplug >> >> operations. When CPUhotplug and some CUPset manipulation take place root >> >> domains are destroyed and new ones created, loosing at the same time DL >> >> accounting pertaining to utilisation. >> > >> > Thanks for looking at this longstanding issue! I am just back from >> > vacations; in the next days I'll try your patches. >> > Do you have some kind of scripts for reproducing the issue >> > automatically? (I see that in the original email Steven described how >> > to reproduce it manually; I just wonder if anyone already scripted the >> > test). >> >> I didn't bother scripting it since it is so easy to do. I'm eager to >> see how things work out on your end. > > I ran some tests with your patchset, and I confirm that it fixes the > issue originally pointed out by Steven. >
Good, at least it's a start. > But I still need to run some more tests (I'll continue on Monday). > > I think I found an issue by: > 1) creating two disjoint cpusets (CPUs 0 and 1 in the first cpuset, > CPUs 2 and 3 in the second one) and setting sched_load_balance to 0 > 2) starting a task in one of the two cpusets, and making it > SCHED_DEADLINE <--- up to here, everything looks fine > 3) setting sched_load_balance to 1 <--- At this point, I think there is > a bug: the system has only one root domain, and the task utilization > is summed to it... But the task affinity mask is still the one of > the "old root domain" that was associated with the cpuset where the > task is executing. I can reproduce the problem on my side as well. This is how CPUset works and the expected behaviour. For normal tasks it isn't a problem but I agree with you that for DL tasks, we need to address this. > > I still need to run some experiments about this. Thanks for the time, Mathieu > > > > Thanks, > Luca
