From owner-svn-src-head@FreeBSD.ORG Tue May 20 15:41:18 2014 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 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 34A644D4; Tue, 20 May 2014 15:41:18 +0000 (UTC) Received: from zxy.spb.ru (zxy.spb.ru [195.70.199.98]) (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 E06A12228; Tue, 20 May 2014 15:41:17 +0000 (UTC) Received: from slw by zxy.spb.ru with local (Exim 4.82 (FreeBSD)) (envelope-from ) id 1WmmAD-00067n-T1; Tue, 20 May 2014 19:41:13 +0400 Date: Tue, 20 May 2014 19:41:13 +0400 From: Slawa Olhovchenkov To: Adrian Chadd Subject: Re: svn commit: r265792 - head/sys/kern Message-ID: <20140520154113.GA23318@zxy.spb.ru> References: <201405100053.s4A0rbF9080571@svn.freebsd.org> <20140511083114.GA53503@zxy.spb.ru> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.22 (2013-10-16) X-SA-Exim-Connect-IP: X-SA-Exim-Mail-From: slw@zxy.spb.ru X-SA-Exim-Scanned: No (on zxy.spb.ru); SAEximRunCond expanded to false Cc: "svn-src-head@freebsd.org" , "svn-src-all@freebsd.org" , "src-committers@freebsd.org" X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.18 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: Tue, 20 May 2014 15:41:18 -0000 On Sun, May 11, 2014 at 08:32:34AM -0700, Adrian Chadd wrote: > On 11 May 2014 01:31, Slawa Olhovchenkov wrote: > > On Sat, May 10, 2014 at 12:53:37AM +0000, Adrian Chadd wrote: > > > >> Author: adrian > >> Date: Sat May 10 00:53:36 2014 > >> New Revision: 265792 > >> URL: http://svnweb.freebsd.org/changeset/base/265792 > >> > >> Log: > >> Add in support to optionally pin the swi threads. > >> > >> Under enough load, the swi's can actually be preempted and migrated > >> to other currently free cores. When doing RSS experiments, this lead > >> to the per-CPU TCP timers not lining up any more with the RX CPU said > >> flows were ending up on, leading to increased lock contention. > >> > >> Since there was a little pushback on flipping them on by default, > >> I've left the default at "don't pin." > >> > >> The other less obvious problem here is that the default swi > >> is also the same as the destination swi for CPU #0. So if one > >> pins the swi on CPU #0, there's no default floating swi. > >> > >> A nice future project would be to create a separate swi for > >> the "default" floating swi, as well as per-CPU swis that are > >> (optionally) pinned. > > > > MFC planed? > > I have 10.0 box with aprox. 16Gbit TCP at peak. > > I've no plans to MFC it at the present. > > By itself it shouldn't do very much. The rest of RSS stack and driver > changes have to go in before it'll matter. > > (But if you try it on 10.0 and it changes things, by all means let me know.) I am try on 10.0, but not sure about significant improvement (may be 10%). For current CPU (E5-2650 v2 @ 2.60GHz) hwpmc don't working (1. after collect some data `pmcstat -R sample.out -G out.txt` don't decode any; 2. kldunload hwpmc do kernel crash) and I can't collect detailed profile information.