From owner-freebsd-current@FreeBSD.ORG Fri Nov 19 14:44:55 2010 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 154F1106566C for ; Fri, 19 Nov 2010 14:44:55 +0000 (UTC) (envelope-from jdc@koitsu.dyndns.org) Received: from qmta09.emeryville.ca.mail.comcast.net (qmta09.emeryville.ca.mail.comcast.net [76.96.30.96]) by mx1.freebsd.org (Postfix) with ESMTP id AD09C8FC13 for ; Fri, 19 Nov 2010 14:44:54 +0000 (UTC) Received: from omta14.emeryville.ca.mail.comcast.net ([76.96.30.60]) by qmta09.emeryville.ca.mail.comcast.net with comcast id Z1Xp1f0051HpZEsA92kuka; Fri, 19 Nov 2010 14:44:54 +0000 Received: from koitsu.dyndns.org ([98.248.41.155]) by omta14.emeryville.ca.mail.comcast.net with comcast id Z2ks1f00K3LrwQ28a2ktR8; Fri, 19 Nov 2010 14:44:53 +0000 Received: by icarus.home.lan (Postfix, from userid 1000) id B60DD9B427; Fri, 19 Nov 2010 06:44:52 -0800 (PST) Date: Fri, 19 Nov 2010 06:44:52 -0800 From: Jeremy Chadwick To: Vincent Hoffman Message-ID: <20101119144452.GA67750@icarus.home.lan> References: <20101118182852.GR63683@over-yonder.net> <20101118185635.GA43706@freebsd.org> <20101118170623.7f9c14f3@kan.dnsalias.net> <20101118233731.GA10392@freebsd.org> <4CE5BA37.20604@freebsd.org> <20101119001710.GA14641@freebsd.org> <20101119094207.00004cb4@unknown> <864obdeb85.fsf@srvbsdfenssv.interne.associated-bears.org> <4CE6874C.1060204@unsane.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4CE6874C.1060204@unsane.co.uk> User-Agent: Mutt/1.5.21 (2010-09-15) X-Mailman-Approved-At: Fri, 19 Nov 2010 15:18:20 +0000 Cc: Eric Masson , freebsd-performance@freebsd.org, Current , Stable Subject: Re: TTY task group scheduling 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, 19 Nov 2010 14:44:55 -0000 On Fri, Nov 19, 2010 at 02:18:52PM +0000, Vincent Hoffman wrote: > On 19/11/2010 12:42, Eric Masson wrote: > > Bruce Cran writes: > > > > Hello, > > > >> Google suggests that the work was a GSoC project in 2005 on a pluggable > >> disk scheduler. > > It seems that something similar has found its way in DFlyBSD, dsched. > And indeed to FreeBSD, man gsched. Added sometime round April > http://svn.freebsd.org/viewvc/base/head/sys/geom/sched/README?view=log It's been pointed out on the list a couple times, and I've sent mail to the authors about this, that gsched breaks (very, very badly) things like sysinstall, and does other strange things like leaves trailing periods at the end of its ".sched." labels. This appears to be by design, but I'm still left thinking "?!" It's hard to discern technical innards/workings of GEOM since the documentation is so poor (and reading the code doesn't help, especially with regards to libgeom). IMHO, the gsched "stuff", as a "layer", should probably be moved into the I/O framework by default, with the functionality *disabled* by default and tunables to adjust it. That's just how I feel about it. -- | Jeremy Chadwick jdc@parodius.com | | Parodius Networking http://www.parodius.com/ | | UNIX Systems Administrator Mountain View, CA, USA | | Making life hard for others since 1977. PGP: 4BD6C0CB |