From owner-freebsd-current@FreeBSD.ORG Fri Jun 20 18:47:43 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 6925437B401 for ; Fri, 20 Jun 2003 18:47:43 -0700 (PDT) Received: from web21505.mail.yahoo.com (web21505.mail.yahoo.com [66.163.169.16]) by mx1.FreeBSD.org (Postfix) with SMTP id 09E0C43F85 for ; Fri, 20 Jun 2003 18:47:43 -0700 (PDT) (envelope-from rmhlldr@yahoo.co.uk) Message-ID: <20030621014742.13635.qmail@web21505.mail.yahoo.com> Received: from [194.44.215.131] by web21505.mail.yahoo.com via HTTP; Sat, 21 Jun 2003 02:47:42 BST Date: Sat, 21 Jun 2003 02:47:42 +0100 (BST) From: =?iso-8859-1?q?RMH?= To: current@freebsd.org MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Subject: SMP & CPU_SUSP_HLT X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: rhett@alasir.com List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 21 Jun 2003 01:47:43 -0000 Hello gentlemen, it seems CPU_SUSP_HLT does nothing for SMP kernels. i386/i386/machdep.c: #ifdef SMP static int cpu_idle_hlt = 0; #else static int cpu_idle_hlt = 1; #endif It's noted that when enabled it will result in about 4.2% loss in performance while doing buildworld. I haven't checked with that, but I tested single-threaded applications to suffer for about 2%, what shouldn't be a big difference. Beyond power consumption, suspend on HLT may solve some overheating issues common for multiprocessor systems. At least, it does so in my case. I suggest to remove #ifdef SMP, and place a warning into NOTES. Let people decide. --- Regards, Rhett ________________________________________________________________________ Want to chat instantly with your online friends? Get the FREE Yahoo! Messenger http://uk.messenger.yahoo.com/