From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Kyle Meyer <kyle.meyer@hpe.com>
Cc: linux-kernel@vger.kernel.org, yury.norov@gmail.com,
linux@rasmusvillemoes.dk, mingo@redhat.com, peterz@infradead.org,
juri.lelli@redhat.com, vincent.guittot@linaro.org,
dietmar.eggemann@arm.com, rostedt@goodmis.org,
bsegall@google.com, mgorman@suse.de, bristot@redhat.com,
vschneid@redhat.com, russ.anderson@hpe.com,
dimitri.sivanich@hpe.com, steve.wahl@hpe.com
Subject: Re: [PATCH 2/2 RESEND] sched/topology: Optimize topology_span_sane()
Date: Tue, 9 Apr 2024 19:25:06 +0300 [thread overview]
Message-ID: <ZhVr4i5F1uWyrJ15@smile.fi.intel.com> (raw)
In-Reply-To: <20240409155250.3660517-3-kyle.meyer@hpe.com>
On Tue, Apr 09, 2024 at 10:52:50AM -0500, Kyle Meyer wrote:
> Optimize topology_span_sane() by removing duplicate comparisons.
>
> The total number of comparisons is reduced from N * (N - 1) to
> N * (N - 1) / 2 (per non-NUMA scheduling domain level).
...
> - for_each_cpu(i, cpu_map) {
> - if (i == cpu)
> - continue;
> + for_each_cpu_from(i, cpu_map) {
Hmm... I'm not familiar with the for_each_cpu*(), but from the above
it seems only a single comparison? Or i.o.w. can i ever repeat the value?
And what about i < cpu cases?
--
With Best Regards,
Andy Shevchenko
next prev parent reply other threads:[~2024-04-09 16:25 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-04-09 15:52 [PATCH 0/2 RESEND] sched/topology: Optimize topology_span_sane() Kyle Meyer
2024-04-09 15:52 ` [PATCH 1/2 RESEND] cpumask: Add for_each_cpu_from() Kyle Meyer
2024-04-10 7:26 ` Vincent Guittot
2024-04-09 15:52 ` [PATCH 2/2 RESEND] sched/topology: Optimize topology_span_sane() Kyle Meyer
2024-04-09 16:25 ` Andy Shevchenko [this message]
2024-04-09 19:29 ` Kyle Meyer
2024-04-10 13:47 ` Andy Shevchenko
2024-04-10 7:34 ` Vincent Guittot
2024-04-10 13:27 ` [PATCH 0/2 " Yury Norov
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