From owner-freebsd-current@FreeBSD.ORG Sun Oct 8 22:55:49 2006 Return-Path: X-Original-To: freebsd-current@freebsd.org Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5DDB816A501 for ; Sun, 8 Oct 2006 22:55:49 +0000 (UTC) (envelope-from asmrookie@gmail.com) Received: from wx-out-0506.google.com (wx-out-0506.google.com [66.249.82.237]) by mx1.FreeBSD.org (Postfix) with ESMTP id 323D943D97 for ; Sun, 8 Oct 2006 22:55:25 +0000 (GMT) (envelope-from asmrookie@gmail.com) Received: by wx-out-0506.google.com with SMTP id i27so1339952wxd for ; Sun, 08 Oct 2006 15:55:24 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:sender:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=j6AbLD91WkeLUk0FavLF5JAvuNdNObt3ZHTDyv3uARFXUO/3/VeH+0XUbhFzRbNl0RvWu89U1VV/NT82ZKHSkSrKrd2nH6TMdqWEuVl2aT9aR6SzslXtjIBo2kuqDOHbP/zijASnmFtA9Ha4Si4cikFJjLdcXALaL1X66EY7MsU= Received: by 10.70.32.10 with SMTP id f10mr10054234wxf; Sun, 08 Oct 2006 15:55:24 -0700 (PDT) Received: by 10.70.11.4 with HTTP; Sun, 8 Oct 2006 15:55:24 -0700 (PDT) Message-ID: <3bbf2fe10610081555r67265368sf7f12edbf35bff0d@mail.gmail.com> Date: Mon, 9 Oct 2006 00:55:24 +0200 From: "Attilio Rao" Sender: asmrookie@gmail.com To: "John-Mark Gurney" , "David Xu" , freebsd-current@freebsd.org, "Kip Macy" , "Ivan Voras" In-Reply-To: <20061008225150.GK793@funkthat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <2fd864e0610080423q7ba6bdeal656a223e662a5d@mail.gmail.com> <20061008135031.G83537@demos.bsdclusters.com> <4529667D.8070108@fer.hr> <200610090634.31297.davidxu@freebsd.org> <20061008225150.GK793@funkthat.com> X-Google-Sender-Auth: 5398a05b3abccede Cc: Subject: Re: [PATCH] MAXCPU alterable in kernel config - needs testers X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 08 Oct 2006 22:55:49 -0000 2006/10/9, John-Mark Gurney : > David Xu wrote this message on Mon, Oct 09, 2006 at 06:34 +0800: > > On Monday 09 October 2006 04:58, Ivan Voras wrote: > > > Kip Macy wrote: > > > > It will only cover the single chip Niagara 2 boxes. > > > > > > Oh right, they'll doing multi chips in Niagara 2 :) Go Sun :) > > > > > > Still, single T2 chips should be more common, so I'd guess it will pay > > > to optimize for that case. > > > > > > (For the rest of the audience: Niagara 1 has 32 logical CPUs and > > > supports only one physical CPU/socket; Niagara 2 will have 64 logical > > > CPUs and support > 1 CPUs/sockets; so a 2 socket Niagara 2 box will have > > > 128 logical processors! Cue SciFi music...) > > > > > > Any word on how will they handle migration of threads across sockets (or > > > will it be OS's job)? Judging from T1 architecture, I think such event > > > would create a very large performance penalty, but I'm not an expert. > > > __________ > > > > The current 4BSD scheduler does not handle large number of cores very well, > > also the single sched_lock will be a bottleneck for such a configuration. > > Bad enough that Kip had to reduce HZ down to 100... since sched_lock > ends up serializing ALL cpus when scheduling needs to happen.. How would you see a sched_lock decomposition (and, if it is possible, how many locks it could be decomposed in?) Attilio -- Peace can only be achieved by understanding - A. Einstein