From owner-freebsd-smp Wed May 1 6:54:23 2002 Delivered-To: freebsd-smp@freebsd.org Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by hub.freebsd.org (Postfix) with ESMTP id 5629337B416 for ; Wed, 1 May 2002 06:54:20 -0700 (PDT) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.9.3/8.9.3) with ESMTP id JAA02059 for ; Wed, 1 May 2002 09:54:19 -0400 (EDT) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.11.6/8.9.1) id g41DrnD18153; Wed, 1 May 2002 09:53:49 -0400 (EDT) (envelope-from gallatin@cs.duke.edu) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <15567.62317.677224.3470@grasshopper.cs.duke.edu> Date: Wed, 1 May 2002 09:53:49 -0400 (EDT) To: freebsd-smp@freebsd.org Subject: hlt when idle? X-Mailer: VM 6.75 under 21.1 (patch 12) "Channel Islands" XEmacs Lucid 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 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? Do both CPUs get clock interrupts on x86? Anyway, am I able to remove the SMP ifdef's from the default_halt function (on 4-stable, 2x1GHz PIII) and I have not noticed any change other than a cooler office & longer runtime on a UPS. (I've not timed a buildworld). Thanks, Drew To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-smp" in the body of the message