From owner-svn-src-head@FreeBSD.ORG Wed Jan 21 08:06:35 2015 Return-Path: Delivered-To: svn-src-head@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id B4312330; Wed, 21 Jan 2015 08:06:35 +0000 (UTC) Received: from mail.turbocat.net (heidi.turbocat.net [88.198.202.214]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 6A6A285E; Wed, 21 Jan 2015 08:06:34 +0000 (UTC) Received: from laptop015.home.selasky.org (cm-176.74.213.204.customer.telag.net [176.74.213.204]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.turbocat.net (Postfix) with ESMTPSA id 6BB821FE023; Wed, 21 Jan 2015 09:06:31 +0100 (CET) Message-ID: <54BF5E39.5030007@selasky.org> Date: Wed, 21 Jan 2015 09:07:21 +0100 From: Hans Petter Selasky User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:31.0) Gecko/20100101 Thunderbird/31.3.0 MIME-Version: 1.0 To: Adrian Chadd Subject: Re: svn commit: r277213 - in head: share/man/man9 sys/kern sys/ofed/include/linux sys/sys References: <201501151532.t0FFWV2Y037455@svn.freebsd.org> <54BDD9E1.6090505@selasky.org> <20150120075126.GA42409@kib.kiev.ua> <20150120211137.GY15484@FreeBSD.org> <54BED6FB.8060401@selasky.org> In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Cc: "src-committers@freebsd.org" , Jason Wolfe , "svn-src-all@freebsd.org" , "svn-src-head@freebsd.org" , Gleb Smirnoff , Konstantin Belousov X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 21 Jan 2015 08:06:35 -0000 On 01/21/15 01:49, Adrian Chadd wrote: > You should totally try say, 100,000 active TCP connections on a box. > See what happens to swi0 (clock). > > TL;DR - the lock contention sucks and it takes a chunk of the core up. > The lock contention is highly not good. > > That's why I'd like to see both the callout stuff in its > slightly-better-defined-and-sane state from you/and/ make it so TCP > can use it. > > I'll have to double-check to see if the RSS stuff is all lined up > correctly so we can use it when we create the callouts (well, at inpcb > creation time, right), rather than when we first schedule them. Then > we can experiment with having the initial CPU be specified at callout > create time rather than expecting to be able to move it when we first > schedule it. > > Or, hm, maybe have it so we don't have a CPU chosen until the first > time we schedule the timeout, and if it hasn't been scheduled before, > allow the CPU to be set? Because at that point we aren't migrating it > off f timeout_cpu - it's never been added to it in the first place. Hi Adrian, What you are saying is correct. If you set the initial c_cpu value when the callout is initialized it will run on SWI#X instead of SWI#0. This is fully allowed, so maybe a callout_init_cpu() would be appropriate, to set the initial CPU number for callouts. With regard to the callout the c_cpu value can be different from zero, only the it must remain fixed/constant when there is no lock protecting updates to it! Kip and Gleb: Does adding a callout_init_cpu() function which can be used for existing callouts and in conjunction with CALLOUT_MPSAFE change anything? --HPS