From owner-freebsd-net@FreeBSD.ORG Sun Nov 25 06:43:14 2007 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C7B6816A418; Sun, 25 Nov 2007 06:43:14 +0000 (UTC) (envelope-from darrenr@freebsd.org) Received: from out1.smtp.messagingengine.com (out1.smtp.messagingengine.com [66.111.4.25]) by mx1.freebsd.org (Postfix) with ESMTP id 8932613C442; Sun, 25 Nov 2007 06:43:14 +0000 (UTC) (envelope-from darrenr@freebsd.org) Received: from compute2.internal (compute2.internal [10.202.2.42]) by out1.messagingengine.com (Postfix) with ESMTP id 6D788522FE; Sun, 25 Nov 2007 01:27:27 -0500 (EST) Received: from heartbeat2.messagingengine.com ([10.202.2.161]) by compute2.internal (MEProxy); Sun, 25 Nov 2007 01:27:27 -0500 X-Sasl-enc: 0BccsOsUVw0/WXR9QX1auRKS59oAyRkqtnu4um8MBFD5 1195972047 Received: from [192.168.1.235] (64-142-85-108.dsl.dynamic.sonic.net [64.142.85.108]) by mail.messagingengine.com (Postfix) with ESMTP id BBF1720357; Sun, 25 Nov 2007 01:27:26 -0500 (EST) Message-ID: <47491532.1050600@freebsd.org> Date: Sat, 24 Nov 2007 22:24:50 -0800 From: Darren Reed User-Agent: Thunderbird 2.0.0.0 (Windows/20070326) MIME-Version: 1.0 To: Max Laier References: <200711231232.04447.max@love2party.net> <20071123132453.W98338@fledge.watson.org> <200711242006.04753.max@love2party.net> In-Reply-To: <200711242006.04753.max@love2party.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-net@freebsd.org, freebsd-current@freebsd.org, Robert Watson Subject: Re: Switch pfil(9) to rmlocks X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 25 Nov 2007 06:43:14 -0000 Max Laier wrote: > On Friday 23 November 2007, Robert Watson wrote: > > On Fri, 23 Nov 2007, Max Laier wrote: > > > attached is a diff to switch the pfil(9) subsystem to rmlocks, which > > > are more suited for the task. I'd like some exposure before doing > > > the switch, but I don't expect any fallout. This email is going > > > through the patched pfil already - twice. > > > > Max, > > > > Have you done performance measurements that show rmlocks to be a win in > > this scenario? I did some patchs for UNIX domain sockets to replace > > the rwlock there but it appeared not to have a measurable impact on SQL > > benchmarks, presumbaly because the read/write blend wasn't right and/or > > that wasnt a significant source of overhead in the benchmark. I'd > > anticipate a much more measurable improvement for pfil, but would be > > interested in learning how much is seen? > > I had to roll an artificial benchmark in order to see a significant change > (attached - it's a hack!). > > Using 3 threads on a 4 CPU machine I get the following results: > null hook: ~13% +/- 2 > mtx hook: up to 40% [*] > rw hook: ~5% +/- 1 > rm hook: ~35% +/- 5 > Is that 13%/5%/35% faster or slower or improvement or degradation? If "rw hook" (using rwlock like we have today?) is 5%, whas is the baseline? I'm expecting that at least one of these should be a 0%... Darren