From owner-freebsd-current@FreeBSD.ORG Sat Nov 24 19:05:08 2007 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E316416A421; Sat, 24 Nov 2007 19:05:08 +0000 (UTC) (envelope-from max@love2party.net) Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.126.179]) by mx1.freebsd.org (Postfix) with ESMTP id 647A313C458; Sat, 24 Nov 2007 19:05:08 +0000 (UTC) (envelope-from max@love2party.net) Received: from amd64.laiers.local (dslb-088-066-037-134.pools.arcor-ip.net [88.66.37.134]) by mrelayeu.kundenserver.de (node=mrelayeu4) with ESMTP (Nemesis) id 0ML21M-1Iw0JI2WHo-0002in; Sat, 24 Nov 2007 20:05:01 +0100 From: Max Laier Organization: FreeBSD To: Robert Watson Date: Sat, 24 Nov 2007 20:05:55 +0100 User-Agent: KMail/1.9.7 References: <200711231232.04447.max@love2party.net> <20071123132453.W98338@fledge.watson.org> In-Reply-To: <20071123132453.W98338@fledge.watson.org> X-Face: ,,8R(x[kmU]tKN@>gtH1yQE4aslGdu+2]; R]*pL,U>^H?)gW@49@wdJ`H<=?utf-8?q?=25=7D*=5FBD=0A=09U=5For=3D=5CmOZf764=26nYj=3DJYbR1PW0ud?=>|!~,,CPC.1-D$FG@0h3#'5"k{V]a~.<=?utf-8?q?mZ=7D44=23Se=7Em=0A=09Fe=7E=5C=5DX5B=5D=5Fxj?=(ykz9QKMw_l0C2AQ]}Ym8)fU MIME-Version: 1.0 Content-Type: multipart/signed; boundary="nextPart2551595.pF8jQdSoQI"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200711242006.04753.max@love2party.net> X-Provags-ID: V01U2FsdGVkX19NDmk3xgnIoeVWGLx2pyn3QslXXgAVHdV9KOY CUiUtH4U43XTcjEyC1Tdk0ih8DSOwmf4W6wgTh3HhEeuFV+y0I zhVy5HFB/CCe6gT6gDTxsIYqo17zFrMjWO3neFzWxs= X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: freebsd-net@freebsd.org, freebsd-current@freebsd.org Subject: Re: Switch pfil(9) to rmlocks X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 24 Nov 2007 19:05:09 -0000 --nextPart2551595.pF8jQdSoQI Content-Type: multipart/mixed; boundary="Boundary-01=_VYHSH3/ckykvJ7C" Content-Transfer-Encoding: 7bit Content-Disposition: inline --Boundary-01=_VYHSH3/ckykvJ7C Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Content-Disposition: inline On Friday 23 November 2007, Robert Watson wrote: > On Fri, 23 Nov 2007, Max Laier wrote: > > attached is a diff to switch the pfil(9) subsystem to rmlocks, which > > are more suited for the task. I'd like some exposure before doing > > the switch, but I don't expect any fallout. This email is going > > through the patched pfil already - twice. > > Max, > > Have you done performance measurements that show rmlocks to be a win in > this scenario? I did some patchs for UNIX domain sockets to replace > the rwlock there but it appeared not to have a measurable impact on SQL > benchmarks, presumbaly because the read/write blend wasn't right and/or > that wasnt a significant source of overhead in the benchmark. I'd > anticipate a much more measurable improvement for pfil, but would be > interested in learning how much is seen? I had to roll an artificial benchmark in order to see a significant change= =20 (attached - it's a hack!). Using 3 threads on a 4 CPU machine I get the following results: null hook: ~13% +/- 2 mtx hook: up to 40% [*] rw hook: ~5% +/- 1 rm hook: ~35% +/- 5 [*] The mtx hook is inconclusive as my measurements vary a lot. If one=20 thread gets lucky and keeps running the overall time obviously goes down=20 by a magnitude. It seems however, that rmlocks greatly increase the=20 chance of that happening - not sure if that's a good thing, though. If=20 all threads receive approximately equal runtime (which is almost always=20 the case for rwlocks) the difference is somewhere around 10%. =2D-=20 /"\ Best regards, | mlaier@freebsd.org \ / Max Laier | ICQ #67774661 X http://pf4freebsd.love2party.net/ | mlaier@EFnet / \ ASCII Ribbon Campaign | Against HTML Mail and News --Boundary-01=_VYHSH3/ckykvJ7C-- --nextPart2551595.pF8jQdSoQI Content-Type: application/pgp-signature; name=signature.asc Content-Description: This is a digitally signed message part. -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.4 (FreeBSD) iD8DBQBHSHYcXyyEoT62BG0RAty0AJ9O9jhwX/vhmb0AKyJ9D+C7lb6neQCdHP3F RIgPL0xZnNMVnmRDtwHckrA= =RdcO -----END PGP SIGNATURE----- --nextPart2551595.pF8jQdSoQI--