From owner-freebsd-hackers Thu Oct 29 21:29:39 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id VAA00475 for freebsd-hackers-outgoing; Thu, 29 Oct 1998 21:29:39 -0800 (PST) (envelope-from owner-freebsd-hackers@FreeBSD.ORG) Received: from dingo.cdrom.com (castles148.castles.com [208.214.165.148]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id VAA00470 for ; Thu, 29 Oct 1998 21:29:37 -0800 (PST) (envelope-from mike@dingo.cdrom.com) Received: from dingo.cdrom.com (LOCALHOST [127.0.0.1]) by dingo.cdrom.com (8.9.1/8.8.8) with ESMTP id VAA00927; Thu, 29 Oct 1998 21:29:11 -0800 (PST) (envelope-from mike@dingo.cdrom.com) Message-Id: <199810300529.VAA00927@dingo.cdrom.com> X-Mailer: exmh version 2.0.2 2/24/98 To: Peter Jeremy cc: hackers@FreeBSD.ORG Subject: Re: sync writes with softupdates enabled In-reply-to: Your message of "Fri, 30 Oct 1998 16:21:51 +1100." <98Oct30.162123est.40365@border.alcanet.com.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 29 Oct 1998 21:29:10 -0800 From: Mike Smith Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > I've just installed 3.0-RELEASE on the machine destined to be our new > news server. Whilst testing it with soft updates enabled, I'm seeing > a lot of sync writes onto /usr: > > /dev/wd0s1f on /usr (local, soft-updates, writes: sync 32910 async 4955) > > With /usr mounted asynchronously rather than soft updates enabled, > I also saw lots of synchronous writes. > > The writes are definitely a result of innd - nothing else much is > running and pausing innd makes the I/O stop. I've looked at a > ktrace of innd and can't see anything that would obviously cause it > to do sync writes (no fsync() or open(O_SYNC) calls). > > It's inn-1.7.2 as per the ports with the exception that MMAP is > enabled for dbz. > > All I can think of is that the MMAP'd history file is causing the > kernel to unnecessarily perform sync writes to try and keep the > MMAP and VFS images in sync. That's almost certainly correct. Try running without mmap. It used to be faster that way; maybe it is again? -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message