From owner-freebsd-current@FreeBSD.ORG Wed Jul 9 08:38:20 2003 Return-Path: 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 D41E337B401 for ; Wed, 9 Jul 2003 08:38:20 -0700 (PDT) Received: from mail.speakeasy.net (mail8.speakeasy.net [216.254.0.208]) by mx1.FreeBSD.org (Postfix) with ESMTP id DFA7243F75 for ; Wed, 9 Jul 2003 08:38:19 -0700 (PDT) (envelope-from jhb@FreeBSD.org) Received: (qmail 3112 invoked from network); 9 Jul 2003 15:38:19 -0000 Received: from unknown (HELO server.baldwin.cx) ([216.27.160.63]) (envelope-sender )encrypted SMTP for ; 9 Jul 2003 15:38:19 -0000 Received: from laptop.baldwin.cx (gw1.twc.weather.com [216.133.140.1]) by server.baldwin.cx (8.12.9/8.12.9) with ESMTP id h69FcHGI099056; Wed, 9 Jul 2003 11:38:17 -0400 (EDT) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.5.4 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <3F0BBB3B.EF2F5687@mindspring.com> Date: Wed, 09 Jul 2003 11:38:31 -0400 (EDT) From: John Baldwin To: Terry Lambert cc: FreeBSD current users cc: Julian Elischer Subject: Re: SMP and setrunnable()- scheduler 4bsd X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 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: Wed, 09 Jul 2003 15:38:21 -0000 On 09-Jul-2003 Terry Lambert wrote: > John Baldwin wrote: >> This is why HLT is not enabled in SMP by default (or at least was, >> it may be turned on now). Given that the clock interrupts are >> effectively broadcast to all CPU's one way or another for all >> arch's (that I know of), you will never halt more than the interval >> between clock ticks on any CPU. > > I thought that there was either a SPARC or Alpha box where Poul > had to mess with the divider because they were delivered round > robin, instead? No. The only anomaly I know of is that on Alpha 2100's, the clock interrupt seems to be round robin rather than broadcast (it is broadcast on all other SMP Alpha's as far as we can tell.) So far we aren't sure exactly how off it is so there isn't a correction in the tree. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/