From owner-freebsd-current@FreeBSD.ORG Fri Nov 23 13:42:49 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 34E7416A41A; Fri, 23 Nov 2007 13:42:49 +0000 (UTC) (envelope-from max@love2party.net) Received: from moutng.kundenserver.de (moutng.kundenserver.de [212.227.126.183]) by mx1.freebsd.org (Postfix) with ESMTP id 9FD3713C442; Fri, 23 Nov 2007 13:42:48 +0000 (UTC) (envelope-from max@love2party.net) Received: from amd64.laiers.local (dslb-088-066-054-138.pools.arcor-ip.net [88.66.54.138]) by mrelayeu.kundenserver.de (node=mrelayeu7) with ESMTP (Nemesis) id 0ML2xA-1IvYnr2ziI-0006T3; Fri, 23 Nov 2007 14:42:46 +0100 From: Max Laier Organization: FreeBSD To: Robert Watson Date: Fri, 23 Nov 2007 14:43:02 +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="nextPart2052720.Kae1ot7PxS"; protocol="application/pgp-signature"; micalg=pgp-sha1 Content-Transfer-Encoding: 7bit Message-Id: <200711231443.13353.max@love2party.net> X-Provags-ID: V01U2FsdGVkX19V9zsBcbIfzUGP/8rYgxu5P+iHMDORSZwY2YA K8bfDz1u+r82VktiM21AfJnlUQSsMkd1/3wrhXz984ovyjf87e ooBMRmeOUZvvckxdRG8WP6WjzirAGQaXKgDqJj58Yc= 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: Fri, 23 Nov 2007 13:42:49 -0000 --nextPart2052720.Kae1ot7PxS 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 don't yet, but will see if I can collect some data later today. The=20 main reason for the switch is shortcomings in rwlock's (not)=20 implementation of reader recursion as discussed in -arch "rwlocks,=20 correctness over speed." rmlocks do that correctly, afaiu. Unless an artificial no-op hook is used, I don't expect to see significant= =20 performance gain, however. All current pfil(9) consumer need some form=20 of synchronization of their own, which will probably nullify the gain=20 from rmlocks. =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 --nextPart2052720.Kae1ot7PxS 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) iD8DBQBHRtjxXyyEoT62BG0RAoekAJ9FA1CTVdhUjqjfQj65eAuJ7BoREACfVjrH /BxWSf8Hep0pleUb7ggxYAU= =3vst -----END PGP SIGNATURE----- --nextPart2052720.Kae1ot7PxS--