From owner-cvs-all Wed Jan 29 19:30:57 2003 Delivered-To: cvs-all@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3FA2C37B401 for ; Wed, 29 Jan 2003 19:30:56 -0800 (PST) Received: from canning.wemm.org (canning.wemm.org [192.203.228.65]) by mx1.FreeBSD.org (Postfix) with ESMTP id EB32143F93 for ; Wed, 29 Jan 2003 19:30:55 -0800 (PST) (envelope-from peter@wemm.org) Received: from wemm.org (localhost [127.0.0.1]) by canning.wemm.org (Postfix) with ESMTP id D17962A89E; Wed, 29 Jan 2003 19:30:55 -0800 (PST) (envelope-from peter@wemm.org) X-Mailer: exmh version 2.5 07/13/2001 with nmh-1.0.4 To: "Matthew D. Fuller" Cc: cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sys/dev/acpica acpi_cpu.c In-Reply-To: <20030130031234.GB1224@over-yonder.net> Date: Wed, 29 Jan 2003 19:30:55 -0800 From: Peter Wemm Message-Id: <20030130033055.D17962A89E@canning.wemm.org> Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.ORG "Matthew D. Fuller" wrote: > On Wed, Jan 29, 2003 at 05:27:06PM -0800 I heard the voice of > Peter Wemm, and lo! it spake thus: > > > > This is a bit old, but it can cause a slight slowdown, because it may take > > a little longer for a cpu to notice a job sitting on the run queue that it > > could have been running. Once it does a halt, it will stop checking until > > the next interrupt (sometimes a clock, sometimes disk/net/etc). This > > Did I miss something somewhere? Does this now work correctly on SMP? Or > is that only with ACPI? With HTT enabled, it is absolutely essential. Having the idle loop on a logical cpu sitting in a hard spin and stealing execution resources from the other logical cpus is not an option. It just so happens that the cost of doing it by default (slight slowdown) has some benefits to counteract the slight cost.. ie: significantly lower temperatures and power consumption. I've been thinking about adding some pretty basic tweaks to avoid the slowdown. It's easier to do on 4.x than 5.x. Cheers, -Peter -- Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com "All of this is for nothing if we don't go to the stars" - JMS/B5 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message