From owner-freebsd-smp Wed May 1 13:16:37 2002 Delivered-To: freebsd-smp@freebsd.org Received: from mail.speakeasy.net (mail13.speakeasy.net [216.254.0.213]) by hub.freebsd.org (Postfix) with ESMTP id C39A037B421 for ; Wed, 1 May 2002 13:16:33 -0700 (PDT) Received: (qmail 10642 invoked from network); 1 May 2002 20:16:31 -0000 Received: from unknown (HELO server.baldwin.cx) ([216.27.160.63]) (envelope-sender ) by mail13.speakeasy.net (qmail-ldap-1.03) with DES-CBC3-SHA encrypted SMTP for ; 1 May 2002 20:16:31 -0000 Received: from laptop.baldwin.cx (gw1.twc.weather.com [216.133.140.1]) by server.baldwin.cx (8.11.6/8.11.6) with ESMTP id g41KGSF04381; Wed, 1 May 2002 16:16:28 -0400 (EDT) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.5.2 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <15567.62317.677224.3470@grasshopper.cs.duke.edu> Date: Wed, 01 May 2002 16:15:28 -0400 (EDT) From: John Baldwin To: Andrew Gallatin Subject: RE: hlt when idle? Cc: freebsd-smp@freebsd.org Sender: owner-freebsd-smp@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org On 01-May-2002 Andrew Gallatin wrote: > > > Can somebody remind me why we do not hlt in the idle loop on MP x86s? > Is this because a HLTed CPU is not going to notice a new runnable job > (possibly migrating from another CPU) until it gets an interrupt to > wake it up? Yes. > Do both CPUs get clock interrupts on x86? No, the interrupts seem to be round-robin, but each clock intr is only sent to one CPU unlike on alpha where they are broadcast. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message