Date: Tue, 24 Jan 2017 00:34:41 +1100 (EST) From: Bruce Evans <brde@optusnet.com.au> To: Andriy Gapon <avg@freebsd.org> Cc: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: Re: svn commit: r312666 - stable/10/sys/kern Message-ID: <20170124002712.Q903@besplex.bde.org> In-Reply-To: <201701230834.v0N8Ypnu011042@repo.freebsd.org> References: <201701230834.v0N8Ypnu011042@repo.freebsd.org>
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On Mon, 23 Jan 2017, Andriy Gapon wrote: > ============================================================================== > --- stable/10/sys/kern/sched_4bsd.c Mon Jan 23 08:34:41 2017 (r312665) > +++ stable/10/sys/kern/sched_4bsd.c Mon Jan 23 08:34:51 2017 (r312666) > @@ -963,8 +963,8 @@ sched_switch(struct thread *td, struct t > sched_load_rem(); > > td->td_lastcpu = td->td_oncpu; > - preempted = !((td->td_flags & TDF_SLICEEND) || > - (flags & SWT_RELINQUISH)); > + preempted = (td->td_flags & TDF_SLICEEND) == 0 && > + (flags & SW_PREEMPT) != 0; > td->td_flags &= ~(TDF_NEEDRESCHED | TDF_SLICEEND); > td->td_owepreempt = 0; > td->td_oncpu = NOCPU; Please also merge to FreeBSD-9. FreeBSD-9 has best performance for a makeworld benchmark. What is a good benchmark for showing that the fix helps? Involuntary context switches increased by almost a factor of 2 for the makeworld benchmark (over nfs) recently, but that was just caused by pessimizations in the NIC driver. Bruce
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