Date: Wed, 21 Nov 2007 20:49:44 +0100 From: Kris Kennaway <kris@FreeBSD.org> To: Alexey Popov <lol@chistydom.ru> Cc: Attilio Rao <attilio@freebsd.org>, freebsd-stable@freebsd.org Subject: Re: 2 x quad-core system is slower that 2 x dual core on FreeBSD Message-ID: <47448BD8.60500@FreeBSD.org> In-Reply-To: <474412CF.5050200@chistydom.ru> References: <4741905E.8050300@chistydom.ru> <fhs3s5$knj$1@ger.gmane.org> <47419AB3.5030008@chistydom.ru> <fhs7hp$2es$2@ger.gmane.org> <4741A7DA.2050706@chistydom.ru> <4741DA15.9000308@FreeBSD.org> <47429DB8.7040504@chistydom.ru> <4742ADFE.40902@FreeBSD.org> <4742C46A.1060701@chistydom.ru> <47432F77.3030606@FreeBSD.org> <474339E9.4080301@FreeBSD.org> <474412CF.5050200@chistydom.ru>
next in thread | previous in thread | raw e-mail | index | archive | help
Alexey Popov wrote: > Hi. > > Kris Kennaway wrote: >>> In the meantime there is unfortunately not a lot that can be done, >>> AFAICT. There is one hack that I will send you later but it is not >>> likely to help much. I will also think about how to track down the >>> cause of the contention further (the profiling trace only shows that >>> it comes mostly from vget/vput but doesn't show where these are >>> called from). >> Actually this patch might help. It doesn't replace lockmgr but it >> does fix a silly thundering herd behaviour. It probably needs some >> adjustment to get it to apply cleanly (it is about 7 months old), and >> I apparently stopped using it because I ran into deadlocks. It might >> be stable enough to at least see how much it helps. > Sorry, I didn't try you patch yet but I have other news. > > As mentioned in the description of your patch there is probably a > scalability problem with stat() syscall on FreeBSD. Not as such, that was just a random example I chose to illustrate the lockmgr problems I described earlier. Try the patch I posted, it should help. Kris
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?47448BD8.60500>