From owner-freebsd-current@FreeBSD.ORG Tue May 23 19:41:09 2006 Return-Path: X-Original-To: current@freebsd.org Delivered-To: freebsd-current@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id C462116A85B for ; Tue, 23 May 2006 19:41:09 +0000 (UTC) (envelope-from kris@obsecurity.org) Received: from elvis.mu.org (elvis.mu.org [192.203.228.196]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7FD8343D46 for ; Tue, 23 May 2006 19:41:09 +0000 (GMT) (envelope-from kris@obsecurity.org) Received: from obsecurity.dyndns.org (elvis.mu.org [192.203.228.196]) by elvis.mu.org (Postfix) with ESMTP id B543C1A4E69; Tue, 23 May 2006 12:41:08 -0700 (PDT) Received: by obsecurity.dyndns.org (Postfix, from userid 1000) id 559995155B; Tue, 23 May 2006 15:41:07 -0400 (EDT) Date: Tue, 23 May 2006 15:41:07 -0400 From: Kris Kennaway To: mlfbsd Message-ID: <20060523194106.GA46634@xor.obsecurity.org> References: <20060522211223.GA3621@xor.obsecurity.org> <20060522231437.GC1446@odin.ac.hmc.edu> <20060523133037.GA2908@gothmog.pc> <20060523143013.GA11472@ci0.org> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="wRRV7LY7NUeQGEoC" Content-Disposition: inline In-Reply-To: <20060523143013.GA11472@ci0.org> User-Agent: Mutt/1.4.2.1i Cc: Giorgos Keramidas , current@freebsd.org, Kris Kennaway Subject: Re: md /tmp and async mounts 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: Tue, 23 May 2006 19:41:16 -0000 --wRRV7LY7NUeQGEoC Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, May 23, 2006 at 04:30:13PM +0200, mlfbsd wrote: > On Tue, May 23, 2006 at 04:30:37PM +0300, Giorgos Keramidas wrote: > > On 2006-05-22 16:14, Brooks Davis wrote: > > >On Mon, May 22, 2006 at 05:12:24PM -0400, Kris Kennaway wrote: > > >> I noticed that with tmpmfs in rc.conf, the md is not being mounted > > >> with -o async; this is an enormous performance boost, so is there a > > >> reason it is not used, or just that it was overlooked? > > > > > > Just overlooked as far as I know. We correctly switched to not mount= ing > > > with softupdates, but should probably switch to -o async. > >=20 > > Right. The only reasons why the current tmpmfs_flags doesn't > > include the `-o async' option too are: > >=20 > > a) It didn't back when it was all hardcoded in the script > >=20 > > b) I didn't think about adding it by default when revision > > 1.230 of src/etc/defaults/rc.conf was committed by me > >=20 > > If it does improve things, we should probably make the change :) > >=20 >=20 > The sys/dev/md/md.c rev 1.115 commit log says async used to be the defaul= t,=20 > but was switched off because it was causing deadlocks. Did this get fixed > since ? You are confusing mdconfig's -o async mode, used only for vnode backing (not the case here anyway): [no]async For vnode backed devices: avoid IO_SYNC for increased performance but at the risk of deadlocking the entire kernel. with mount's -o async mode, used at the filesystem layer on any device. The latter does not have deadlocks. Kris --wRRV7LY7NUeQGEoC Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.3 (FreeBSD) iD8DBQFEc2VSWry0BWjoQKURAs3VAKDcKKY/ba9VT4LH/fPKyiwE+SeqGACglmKK FNza9B4fGo9qtM1nFomjmiY= =J6rv -----END PGP SIGNATURE----- --wRRV7LY7NUeQGEoC--