From owner-cvs-all Thu Oct 24 8:22:55 2002 Delivered-To: cvs-all@freebsd.org Received: by hub.freebsd.org (Postfix, from userid 931) id EB02637B401; Thu, 24 Oct 2002 08:22:53 -0700 (PDT) Date: Thu, 24 Oct 2002 08:22:53 -0700 From: Juli Mallett To: Poul-Henning Kamp Cc: Dan Nelson , Kirk McKusick , cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org Subject: Re: cvs commit: src/sys/fs/specfs spec_vnops.c src/sys/kern subr_disk.c src/sys/ufs/ffs ffs_snapshot.c Message-ID: <20021024082253.B57679@FreeBSD.org> References: <20021024145822.GA69650@dan.emsphone.com> <5892.1035472339@critter.freebsd.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: <5892.1035472339@critter.freebsd.dk>; from phk@critter.freebsd.dk on Thu, Oct 24, 2002 at 05:12:19PM +0200 Organisation: The FreeBSD Project X-Alternate-Addresses: , , , , X-Towel: Yes X-LiveJournal: flata, jmallett X-Negacore: Yes Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG * De: Poul-Henning Kamp [ Data: 2002-10-24 ] [ Subjecte: Re: cvs commit: src/sys/fs/specfs spec_vnops.c src/sys/kern subr_disk.c src/sys/ufs/ffs ffs_snapshot.c ] > In message <20021024145822.GA69650@dan.emsphone.com>, Dan Nelson writes: > >In the last episode (Oct 21), Kirk McKusick said: > >> mckusick 2002/10/21 17:59:49 PDT > >> > >> Modified files: > >> sys/fs/specfs spec_vnops.c > >> sys/kern subr_disk.c > >> sys/ufs/ffs ffs_snapshot.c > >> Log: > >> This checkin reimplements the io-request priority hack in a way > >> that works in the new threaded kernel. It was commented out of > > > >I think this cure is worse than the disease. Background fsck times on > >my system went from 10 minutes to an hour, and niced processes that > >want to do any disk I/O at all run at a glacial speed. Try running > >"nice find /" on an otherwise-idle system, for example. Don't bother > >running anything at nice -20 :) > > I as somewhat afraid of this, and therefore floated the idea that > the pacing should be moved all the way up to physio() so it only > affected niced processes which access raw-devices, but Kirk thought > hitting all disk-access was more logical. > > I can't really make up my mind either way. It means (for me) that checking my 4G disk takes 45 minutes total, and during that time, everything has to use a snapshot, and since fsck is going on, snaplck is constantly being blocked on, and so that means that i go from having a very-bogged-down system for 15 minutes, to a useless and frustrating slothy-but-usable-enough-to-not-deter-me system for 45 minutes... I tended to like it better when it got its job over and done with, without taking up such a large chunk of wall clock time. juli. -- Juli Mallett | FreeBSD: The Power To Serve Will break world for fulltime employment. | finger jmallett@FreeBSD.org http://people.FreeBSD.org/~jmallett/ | Support my FreeBSD hacking! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message