Messages in this thread | ![/](/images/icornerl.gif) | | Date | Wed, 31 Jan 2024 17:10:38 -0800 | From | Ricardo Neri <> | Subject | Re: [PATCH v2 6/6 RFT] sched/fair: change sched asym checking condition |
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On Tue, Jan 30, 2024 at 09:17:08PM +0800, alexs@kernel.org wrote: > From: Alex Shi <alexs@kernel.org> > > Asym only used on SMT sd, or core sd with ITMT and core idled. > !sched_smt_active isn't necessary.
sched_smt_active() is implemented as a static key. Thus, if SMT is not enabled, we can quickly return without having to check the rest of the conditions, as we should.
> > Signed-off-by: Alex Shi <alexs@kernel.org> > To: Ricardo Neri <ricardo.neri-calderon@linux.intel.com> > To: linux-kernel@vger.kernel.org > To: Valentin Schneider <vschneid@redhat.com> > To: Daniel Bristot de Oliveira <bristot@redhat.com> > To: Ben Segall <bsegall@google.com> > To: Steven Rostedt <rostedt@goodmis.org> > To: Dietmar Eggemann <dietmar.eggemann@arm.com> > To: Vincent Guittot <vincent.guittot@linaro.org> > To: Juri Lelli <juri.lelli@redhat.com> > To: Peter Zijlstra <peterz@infradead.org> > To: Ingo Molnar <mingo@redhat.com> > --- > kernel/sched/fair.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c > index 6680cb39c787..0b7530b93429 100644 > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -9744,8 +9744,8 @@ static bool sched_use_asym_prio(struct sched_domain *sd, int cpu) > if (!(sd->flags & SD_ASYM_PACKING)) > return false; > > - return (!sched_smt_active()) || > - (sd->flags & SD_SHARE_CPUCAPACITY) || is_core_idle(cpu); > + return (sd->flags & SD_SHARE_CPUCAPACITY) || > + (is_core_idle(cpu) && test_bit(cpu_core_flags(), (void *)&sd->flags));
cpu_core_flags() can contain more than one flag, AFAICS. Which bit should it check? Moreover, it is implemented differently for each architecture. Also, as stated, in x86 asym_packing is also used in domains other than MC.
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