> -----Original Message----- > From: Wanpeng Li [mailto:wanpeng...@hotmail.com] > Sent: Tuesday, September 08, 2015 5:39 PM > To: Byungchul Park > Cc: Peter Zijlstra; Ingo Molnar; linux-kernel@vger.kernel.org; > yuyang...@intel.com > Subject: Re: [PATCH] sched: fix lose fair sleeper bonus in switch_to_fair() > > On 9/8/15 4:22 PM, Byungchul Park wrote: > > On Tue, Sep 08, 2015 at 04:04:49PM +0800, Wanpeng Li wrote: > >>>> However, if se->vruntime -= cfs_rq->min_vruntime is positive, the > >>>> behavior is different after your patch. e.g. se->vruntime(the > >>>> relative vruntime in switched_to_fair()) < min_vruntime - > >>>> sysctl_sched_latency/2 > >>>> > >>>> before your patch: > >>>> > >>>> se->vruntime = min_vruntime - sysctl_sched_latency/2 (place_entity()) > >>> my patch is based on ff277d4 commit at tip/sched/core.
Look at this. > >>> > >>> there's no change between before and after. > >>> > >>> check it please. > >>> > >>> and this logic seems to be no problem to me. :( > >> Your logic will lose fair sleeper bonus in the scenario which I pointed > out. > > i mean in ff277d4 commit: > > Please include the commit subject when you point out a commit, do you > mean this one? I said "I based my patch on ff277d4 commit". > > commit ff277d4250fe715b6666219b1a3423b863418794 > Author: Andrea Parri <parri.and...@gmail.com> > Date: Wed Aug 5 15:56:19 2015 +0200 > > sched/deadline: Fix comment in enqueue_task_dl() > > The "dl_boosted" flag is set by comparing *absolute* deadlines > (c.f., rt_mutex_setprio()). > > > What's the relationship w/ this patch? Nothing. Just a base commit. > > Regards, > Wanpeng Li > > > > > se->vruntime += cfs->min_vruntime (switched_to_fair()) > > se->vruntime = se->vruntime or bonused value (place_entity()) > > > > after my patch: > > > > se->vruntime += cfs->min_vruntime (switched_to_fair()) > > se->vruntime = se->vruntime or bonused value (place_entity()) > > > > --- > > > > SAME!!! > > > > in addtion, se->vruntime already had a bonused value if eligible, > > when it was detached from cfs_rq. > > > >>>> after your patch: > >>>> > >>>> se->vruntime += cfs->min_vruntime (switched_to_fair()) > >>>> se->vruntime = se->vruntime (place_entity()) > >>>> > >>>> > >>>> Regards, > >>>> Wanpeng Li > >>>> > >>>> -- > >>>> To unsubscribe from this list: send the line "unsubscribe linux- > kernel" in > >>>> the body of a message to majord...@vger.kernel.org > >>>> More majordomo info at http://vger.kernel.org/majordomo-info.html > >>>> Please read the FAQ at http://www.tux.org/lkml/ > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" > in > >> the body of a message to majord...@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> Please read the FAQ at http://www.tux.org/lkml/ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/