Date: Tue, 6 Feb 2007 11:59:27 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: Alan Cox <alc@FreeBSD.org> Cc: cvs-src@FreeBSD.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/vm vm_contig.c vm_page.c vm_pageq.c vm_zeroidle.c Message-ID: <20070206115809.K32369@fledge.watson.org> In-Reply-To: <200702050602.l1562tnI034504@repoman.freebsd.org> References: <200702050602.l1562tnI034504@repoman.freebsd.org>
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On Mon, 5 Feb 2007, Alan Cox wrote: > alc 2007-02-05 06:02:55 UTC > > FreeBSD src repository > > Modified files: > sys/vm vm_contig.c vm_page.c vm_pageq.c > vm_zeroidle.c > Log: > Change the free page queue lock from a spin mutex to a default (blocking) > mutex. With the demise of Alpha support, there is no longer a reason for > it to be a spin mutex. Is there any measurable performance change from this? In the past, I've observed significantly higher cost for acquiring spin mutexes vs. sleep mutexes in micro-benchmarking. The change was most striking on Intel Xeon P4 hardware with an SMP kernel, and quite a bit less so on other platforms. Robert N M Watson Computer Laboratory University of Cambridge
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