Date: Wed, 10 Apr 2013 10:20:59 +0400 From: Gleb Smirnoff <glebius@FreeBSD.org> To: Andre Oppermann <andre@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r249318 - in head/sys: kern net netinet Message-ID: <20130410062059.GZ76816@FreeBSD.org> In-Reply-To: <201304092102.r39L2LrO047044@svn.freebsd.org> References: <201304092102.r39L2LrO047044@svn.freebsd.org>
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On Tue, Apr 09, 2013 at 09:02:21PM +0000, Andre Oppermann wrote: A> Author: andre A> Date: Tue Apr 9 21:02:20 2013 A> New Revision: 249318 A> URL: http://svnweb.freebsd.org/changeset/base/249318 A> A> Log: A> Change certain heavily used network related mutexes and rwlocks to A> reside on their own cache line to prevent false sharing with other A> nearby structures, especially for those in the .bss segment. A> A> NB: Those mutexes and rwlocks with variables next to them that get A> changed on every invocation do not benefit from their own cache line. A> Actually it may be net negative because two cache misses would be A> incurred in those cases. Although change is theoretically correct, IMO, such change should be supported by experimental performance benchmarking data. -- Totus tuus, Glebius.
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