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Date: Thu, 11 Apr 2024 16:55:11 -0500
From: Kyle Meyer <kyle.meyer@hpe.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, yury.norov@gmail.com,
        linux@rasmusvillemoes.dk, mingo@redhat.com, peterz@infradead.org,
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        russ.anderson@hpe.com, dimitri.sivanich@hpe.com, steve.wahl@hpe.com
Subject: Re: [PATCH v2 2/2] sched/topology: Optimize topology_span_sane()
References: <20240410213311.511470-1-kyle.meyer@hpe.com>
 <20240410213311.511470-3-kyle.meyer@hpe.com>
 <Zhe9ttm9Ppv2wT3S@smile.fi.intel.com>
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In-Reply-To: <Zhe9ttm9Ppv2wT3S@smile.fi.intel.com>

On Thu, Apr 11, 2024 at 01:38:46PM +0300, Andy Shevchenko wrote:
> On Wed, Apr 10, 2024 at 04:33:11PM -0500, Kyle Meyer wrote:
> > Optimize topology_span_sane() by removing duplicate comparisons.
> > 
> > Since topology_span_sane() is called inside of for_each_cpu(), each
> > pervious CPU has already been compared against every other CPU. The
> 
> previous

Thank you for pointing that out. Should I send an updated version or can
a maintainer correct my mistake?

> > current CPU only needs to be compared against higher-numbered CPUs.
> > 
> > The total number of comparisons is reduced from N * (N - 1) to
> > N * (N - 1) / 2 on each non-NUMA scheduling domain level.
> 
> Thank you, now it makes sense.

Thanks,
Kyle Meyer