Date: Tue, 9 May 2006 11:13:02 -0700 From: "Greg 'groggy' Lehey" <grog@FreeBSD.org> To: Kris Kennaway <kris@obsecurity.org> Cc: Robert Watson <rwatson@FreeBSD.org>, performance@FreeBSD.org, current@FreeBSD.org Subject: Re: Fine-grained locking for POSIX local sockets (UNIX domain sockets) Message-ID: <20060509181302.GD3636@eucla.lemis.com> In-Reply-To: <20060509011109.GA57060@xor.obsecurity.org> References: <20060506150622.C17611@fledge.watson.org> <20060506221908.GB51268@xor.obsecurity.org> <20060507210426.GA4422@xor.obsecurity.org> <20060507214153.GA5275@xor.obsecurity.org> <20060507230430.GA6872@xor.obsecurity.org> <20060508065207.GA20386@xor.obsecurity.org> <20060509004328.GB55852@xor.obsecurity.org> <20060509011109.GA57060@xor.obsecurity.org>
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--IMjqdzrDRly81ofr Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Monday, 8 May 2006 at 21:11:09 -0400, Kris Kennaway wrote: > On Mon, May 08, 2006 at 08:43:28PM -0400, Kris Kennaway wrote: >> On Mon, May 08, 2006 at 02:52:07AM -0400, Kris Kennaway wrote: >>> OK, David's patch fixes the umtx thundering herd (and seems to give a >>> 4-6% boost). I also fixed a thundering herd in FILEDESC_UNLOCK (which >>> was also waking up 2-7 CPUs at once about 30% of the time) by doing >>> s/wakeup/wakeup_one/. This did not seem to give a performance impact >>> on this test though. >> >> Turning down kern.hz from 1000 to 100 also made a big difference on 12 >> CPUs (+6.1%). >> >> Note also that the system is no less than 40% idle during the runs (at >> any load), so the bottlenecks are serious. > > top -H shows the threads mostly in umtx state. This doesn't lend much support to the idea that the gettimeofday() calls are a bottleneck. I've just been through the code, but if there are any mutexes acquired there, I missed them. Greg -- See complete headers for address and phone numbers --IMjqdzrDRly81ofr Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (FreeBSD) iD8DBQFEYNutIubykFB6QiMRAhriAJ9eot/N1vVl0VsXdZX0JocYC7/qxACfSM+V GyLMmRNfOAhK+sLjc7M4YsQ= =vjXK -----END PGP SIGNATURE----- --IMjqdzrDRly81ofr--
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