From owner-freebsd-current Sat Jun 6 12:18:35 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id MAA09414 for freebsd-current-outgoing; Sat, 6 Jun 1998 12:18:35 -0700 (PDT) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from dyson.iquest.net (dyson.iquest.net [198.70.144.127]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id MAA09395; Sat, 6 Jun 1998 12:18:27 -0700 (PDT) (envelope-from toor@dyson.iquest.net) Received: (from root@localhost) by dyson.iquest.net (8.8.8/8.8.8) id OAA06021; Sat, 6 Jun 1998 14:18:21 -0500 (EST) (envelope-from toor) Message-Id: <199806061918.OAA06021@dyson.iquest.net> Subject: Re: New SMP perf/quality snapshot (Update) In-Reply-To: from Julian Elischer at "Jun 6, 98 10:17:03 am" To: julian@whistle.com (Julian Elischer) Date: Sat, 6 Jun 1998 14:18:20 -0500 (EST) Cc: dyson@FreeBSD.ORG, current@FreeBSD.ORG From: "John S. Dyson" Reply-To: dyson@FreeBSD.ORG X-Mailer: ELM [version 2.4ME+ PL38 (25)] MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG Julian Elischer said: > > John, one of the changes you asked kirk and I to implement was > the change do a simple tailq (stailq) to a doubly linked list. > > Kirk asked the reason that you thought this was a speed improvement > but I think it was at a time that you were being pressured > elsewhere and couldn't answer. > > If you could supply this answer then kirk might implememt the > change in his sources and we can keep in step again.. > > I notice that your patches include this change so I'm anxious > to get everything sync'd up again.. > The reason is the way that we maintain the dirty list in vfs_subr. We need to place the metadata at the end of the dirty list. This might not be very useful for softupdates, but is very valuable for -async. We were incorrectly flushing metadata first (and unnecessarily) for -async. There is a very measurable performance improvement with this change. -- John | Never try to teach a pig to sing, dyson@freebsd.org | it just makes you look stupid, jdyson@nc.com | and it irritates the pig. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message