From: "Li, Aubrey" <aubrey.li@linux.intel.com>
To: Vincent Guittot <vincent.guittot@linaro.org>,
Mel Gorman <mgorman@techsingularity.net>
Cc: Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Valentin Schneider <valentin.schneider@arm.com>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] sched/fair: Clear SMT siblings after determining the core is not idle
Date: Tue, 1 Dec 2020 09:04:06 +0800 [thread overview]
Message-ID: <f31178dd-34e4-0e9d-e8e3-fda396641daf@linux.intel.com> (raw)
In-Reply-To: <CAKfTPtBcZnxR073=eRsWNAGOnA8K4emL0BYEUzbkzZx6qJWmSg@mail.gmail.com>
On 2020/11/30 22:47, Vincent Guittot wrote:
> On Mon, 30 Nov 2020 at 15:40, Mel Gorman <mgorman@techsingularity.net> wrote:
>>
>> The clearing of SMT siblings from the SIS mask before checking for an idle
>> core is a small but unnecessary cost. Defer the clearing of the siblings
>> until the scan moves to the next potential target. The cost of this was
>> not measured as it is borderline noise but it should be self-evident.
>
> Good point
This is more reasonable, thanks Mel.
>
>>
>> Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
>
> Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
>
>> ---
>> kernel/sched/fair.c | 3 ++-
>> 1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
>> index 0d54d69ba1a5..d9acd55d309b 100644
>> --- a/kernel/sched/fair.c
>> +++ b/kernel/sched/fair.c
>> @@ -6087,10 +6087,11 @@ static int select_idle_core(struct task_struct *p, struct sched_domain *sd, int
>> break;
>> }
>> }
>> - cpumask_andnot(cpus, cpus, cpu_smt_mask(core));
>>
>> if (idle)
>> return core;
>> +
>> + cpumask_andnot(cpus, cpus, cpu_smt_mask(core));
>> }
>>
>> /*
next prev parent reply other threads:[~2020-12-01 1:06 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-30 14:40 [PATCH] sched/fair: Clear SMT siblings after determining the core is not idle Mel Gorman
2020-11-30 14:47 ` Vincent Guittot
2020-12-01 1:04 ` Li, Aubrey [this message]
2020-12-01 11:03 ` Peter Zijlstra
2020-12-03 9:13 ` [tip: sched/core] " tip-bot2 for Mel Gorman
2020-12-11 9:34 ` tip-bot2 for Mel Gorman
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