On 02/13/25 07:20, Juri Lelli wrote: > On 12/02/25 19:22, Dietmar Eggemann wrote: > > On 11/02/2025 11:42, Juri Lelli wrote: > > ... > > > > What about we actually ignore them consistently? We already do that for > > > admission control, so maybe we can do that when rebuilding domains as > > > well (until we find maybe a better way to deal with them). > > > > > > Does the following make any difference? > > > > It at least seems to solve the issue. And like you mentioned on irc, we > > don't know the bw req of sugov anyway. > > > > So with this change we start with 'dl_bw->total_bw = 0' even w/ sugov tasks. > > > > dl_rq[0]: > > .dl_nr_running : 0 > > .dl_bw->bw : 996147 > > .dl_bw->total_bw : 0 <-- ! > > > > IMHO, people who want to run serious DL can always check whether there > > are already these infrastructural DL tasks or even avoid schedutil. > > It definitely not ideal and admittedly gross, but not worse than what we > are doing already considering we ignore sugovs at AC and the current > bandwidth allocation its there only to help with PI. So, duck tape. :/ > > A more proper way to work with this would entail coming up with sensible > bandwidth allocation for sugovs, but that's most probably hardware > specific, so I am not sure how we can make that general enough. I haven't been following the problem closely, but one thing I was considering and I don't know if it makes sense to you and could help with this problem too. Shall we lump sugov with stopper class or create a new sched_class (seems unnecessary, I think stopper should do)? With the consolidate cpufreq update patch I've been working on Vincent raised issues with potential new ctx switch and to improve that I needed to look at improving sugov wakeup path. If we decouple it from DL I think that might fix your problem here and could allow us to special case it for other problems like the ones I faced more easily without missing up with DL. Has the time come to consider retire the simple solution of making sugov a fake DL task? > > Anyway, looks like Jon was still seeing the issue. I asked him to verify > he is using all the proposed changes. Let's see what he reports. > > Best, > Juri >
