From owner-svn-src-all@FreeBSD.ORG Sun May 11 15:32:36 2014 Return-Path: Delivered-To: svn-src-all@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 101BDE35; Sun, 11 May 2014 15:32:36 +0000 (UTC) Received: from mail-ve0-x22d.google.com (mail-ve0-x22d.google.com [IPv6:2607:f8b0:400c:c01::22d]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 9FC1F2C88; Sun, 11 May 2014 15:32:35 +0000 (UTC) Received: by mail-ve0-f173.google.com with SMTP id pa12so7635056veb.32 for ; Sun, 11 May 2014 08:32:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=MRHrMXMgfB1+i+3/QzwQzgIWyVZRwF9SIah/L8qYkkE=; b=RWgKDElNMFxU2uqH9p6dMChYnPKTZzDZrx8vTQ2GxnaxcYCUtr944CkJgng9KPlsoV j4DqjKI3uRr/tFk9IVYAAwRTJoPRc7tw1ZASiPkXUYluzC7zzAi7NhsnZdnvXBE6lV4X csvXBZBYZwt+eyppFEWTDywxKX6ds8ZS4Y2b7+9WAke8/AZvzqXb/0BAHJZH5auS1YYA Phb3rRn1pCCCX/zXIXCnLO98/5MqUUWNM9xjVKeHLFFabDPlX/mzHIjhCu2y1BiEfI1j iPI4n46XdVMHgzcRUzBlpn2P2pkU9UbWOxZh0pJLvTFFXNkIbZZcJjIB6Ls/ZNImBGn8 4Udg== MIME-Version: 1.0 X-Received: by 10.220.44.20 with SMTP id y20mr316533vce.60.1399822354656; Sun, 11 May 2014 08:32:34 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.220.186.193 with HTTP; Sun, 11 May 2014 08:32:34 -0700 (PDT) In-Reply-To: <20140511083114.GA53503@zxy.spb.ru> References: <201405100053.s4A0rbF9080571@svn.freebsd.org> <20140511083114.GA53503@zxy.spb.ru> Date: Sun, 11 May 2014 08:32:34 -0700 X-Google-Sender-Auth: Y-9WkJRyllJ_-OCYkthmdJrkyQI Message-ID: Subject: Re: svn commit: r265792 - head/sys/kern From: Adrian Chadd To: Slawa Olhovchenkov Content-Type: text/plain; charset=UTF-8 Cc: "svn-src-head@freebsd.org" , "svn-src-all@freebsd.org" , "src-committers@freebsd.org" X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 11 May 2014 15:32:36 -0000 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.) -a