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Date: Tue, 9 Apr 2024 19:25:06 +0300
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,
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	dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com,
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	russ.anderson@hpe.com, dimitri.sivanich@hpe.com, steve.wahl@hpe.com
Subject: Re: [PATCH 2/2 RESEND] sched/topology: Optimize topology_span_sane()
Message-ID: <ZhVr4i5F1uWyrJ15@smile.fi.intel.com>
References: <20240409155250.3660517-1-kyle.meyer@hpe.com>
 <20240409155250.3660517-3-kyle.meyer@hpe.com>
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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