Date: Tue, 4 Dec 2007 12:14:18 +0000 (GMT) From: Robert Watson <rwatson@FreeBSD.org> To: Krassimir Slavchev <krassi@bulinfo.net> Cc: freebsd-stable@freebsd.org, Alexey Popov <lol@chistydom.ru> Subject: Re: 2 x quad-core system is slower that 2 x dual core on FreeBSD Message-ID: <20071204121329.N87930@fledge.watson.org> In-Reply-To: <47553170.90409@bulinfo.net> References: <20071201213732.GA16638@cannabis.dataforce.net> <1497741406.20071201230441@rulez.sk> <20071202174540.GA29572@cannabis.dataforce.net> <200712020844.49718.linimon@FreeBSD.org> <4753C9E4.1060200@chistydom.ru> <20071203114037.G79674@fledge.watson.org> <47542372.3040303@chistydom.ru> <20071203163353.J79674@fledge.watson.org> <47551C1C.3000903@chistydom.ru> <47553170.90409@bulinfo.net>
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On Tue, 4 Dec 2007, Krassimir Slavchev wrote: >>> Evidence in-hand seems to suggest that 8 core systems work very well for >>> most users, and reflect a significant performance increase with 7.0 over >>> previous FreeBSD releases. >> >> I disagree with that. Heavily loaded Apache, MySQL, Postgres does not work >> well. > > There is another report for such problems: > > http://blog.insidesystems.net/articles/2007/04/09/what-did-i-do-wrong A casual reading suggests that this article is about FreeBSD 6.2, and not FreeBSD 7.0. Am I misreading? Robert N M Watson Computer Laboratory University of Cambridge > >> >>>>> The right path forwawrd at this point is to diagnosis the problems >>>>> and work on fixing them in 8-CURRENT, and assuming they are not >>>>> highly disruptive, MFC them for FreeBSD 7.1. >>>> >>>> I believe at least the bug with lockmgr contention should be fixed >>>> before release. >>> Could you point me at the specific proposed change in question? I >>> don't think I've seen it come across re@ as a potential merge >>> request. Changing locking primitives close to a release is, FYI, a >>> risky business, as while it may improve performance in specific cases, >>> we may not have a lot of information about more general cases. We >>> also risk opening up previously nascent race conditions in lock >>> consumers. >> Kris sent me proof of concept patch that helped much against high >> lockmgr contention. After applying this patch 8-core server become >> faster that 4-core. But, again, it's still slower than Linux. >> >> Here's the patch: >> http://lists.freebsd.org/pipermail/freebsd-stable/2007-November/038449.html >> >> Here's Kris saying that it helps: >> http://lists.freebsd.org/pipermail/freebsd-stable/2007-November/038672.html >> >> I'm not sure it will help to MySQL and Prostgres, but symptoms are >> mostly identical. >> >> With best regards, >> Alexey Popov >> _______________________________________________ >> freebsd-stable@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-stable >> To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" >> > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.7 (FreeBSD) > > iD8DBQFHVTFwxJBWvpalMpkRAjX0AJ4otHVzAzVqVRKJxUlD4Y9ENdD5PACgq/eZ > ptzb/VC56JFh/Iiepy+bK/s= > =wpdw > -----END PGP SIGNATURE----- >
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