From owner-freebsd-current@FreeBSD.ORG Sun Oct 8 22:51:59 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 DB21B16A40F; Sun, 8 Oct 2006 22:51:59 +0000 (UTC) (envelope-from jmg@hydrogen.funkthat.com) Received: from hydrogen.funkthat.com (gate.funkthat.com [69.17.45.168]) by mx1.FreeBSD.org (Postfix) with ESMTP id 5570E43D45; Sun, 8 Oct 2006 22:51:59 +0000 (GMT) (envelope-from jmg@hydrogen.funkthat.com) Received: from hydrogen.funkthat.com (l5q3vgeh8i2ftzjk@localhost.funkthat.com [127.0.0.1]) by hydrogen.funkthat.com (8.13.6/8.13.3) with ESMTP id k98MpqHS075610; Sun, 8 Oct 2006 15:51:53 -0700 (PDT) (envelope-from jmg@hydrogen.funkthat.com) Received: (from jmg@localhost) by hydrogen.funkthat.com (8.13.6/8.13.3/Submit) id k98MppXp075609; Sun, 8 Oct 2006 15:51:51 -0700 (PDT) (envelope-from jmg) Date: Sun, 8 Oct 2006 15:51:50 -0700 From: John-Mark Gurney To: David Xu Message-ID: <20061008225150.GK793@funkthat.com> Mail-Followup-To: David Xu , freebsd-current@freebsd.org, Kip Macy , Ivan Voras References: <2fd864e0610080423q7ba6bdeal656a223e662a5d@mail.gmail.com> <20061008135031.G83537@demos.bsdclusters.com> <4529667D.8070108@fer.hr> <200610090634.31297.davidxu@freebsd.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200610090634.31297.davidxu@freebsd.org> User-Agent: Mutt/1.4.2.1i X-Operating-System: FreeBSD 5.4-RELEASE-p6 i386 X-PGP-Fingerprint: B7 EC EF F8 AE ED A7 31 96 7A 22 B3 D8 56 36 F4 X-Files: The truth is out there X-URL: http://resnet.uoregon.edu/~gurney_j/ X-Resume: http://resnet.uoregon.edu/~gurney_j/resume.html Cc: freebsd-current@freebsd.org, Kip Macy , Ivan Voras Subject: Re: [PATCH] MAXCPU alterable in kernel config - needs testers X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list Reply-To: John-Mark Gurney 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 22:51:59 -0000 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.. -- John-Mark Gurney Voice: +1 415 225 5579 "All that I will do, has been done, All that I have, has not."