Date: Tue, 9 Nov 2004 21:08:05 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: Julian Elischer <julian@elischer.org> Cc: Stephan Uphoff <ups@tree.com> Subject: Re: cvs commit: src/sys/i386/i386 pmap.c Message-ID: <Pine.NEB.3.96L.1041109210654.60848A-100000@fledge.watson.org> In-Reply-To: <419109EB.8010809@elischer.org>
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On Tue, 9 Nov 2004, Julian Elischer wrote: > Is this with HTT? > > We've dicoverred that HTT makes better code run slower, remember? Nope, the issue here is a minor tweak in the spin lock code that causes moving away from an atomic operation to make it run slower rather than faster. I think John has a theory that the lack of using an atomic operation slows the rate at which the change is visible on other processors by virtue of being non-atomic, so locks contend longer. Robert N M Watson FreeBSD Core Team, TrustedBSD Projects robert@fledge.watson.org Principal Research Scientist, McAfee Research
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