Messages in this thread | | | From | Vincent Guittot <> | Date | Mon, 27 Feb 2023 15:37:37 +0100 | Subject | Re: [PATCH v3] sched/fair: sanitize vruntime of entity being placed |
| |
On Mon, 27 Feb 2023 at 09:43, Roman Kagan <rkagan@amazon.de> wrote: > > On Tue, Feb 21, 2023 at 06:26:11PM +0100, Vincent Guittot wrote: > > On Tue, 21 Feb 2023 at 17:57, Roman Kagan <rkagan@amazon.de> wrote: > > > What scares me, though, is that I've got a message from the test robot > > > that this commit drammatically affected hackbench results, see the quote > > > below. I expected the commit not to affect any benchmarks. > > > > > > Any idea what could have caused this change? > > > > Hmm, It's most probably because se->exec_start is reset after a > > migration and the condition becomes true for newly migrated task > > whereas its vruntime should be after min_vruntime. > > > > We have missed this condition > > Makes sense to me. > > But what would then be the reliable way to detect a sched_entity which > has slept for long and risks overflowing in .vruntime comparison?
For now I don't have a better idea than adding the same check in migrate_task_rq_fair()
> > Thanks, > Roman. > > > > Amazon Development Center Germany GmbH > Krausenstr. 38 > 10117 Berlin > Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss > Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B > Sitz: Berlin > Ust-ID: DE 289 237 879 > > >
| |