From owner-freebsd-net@FreeBSD.ORG Tue Nov 8 01:38:02 2005 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8F5AF16A420; Tue, 8 Nov 2005 01:38:02 +0000 (GMT) (envelope-from vaibhave@cs.utah.edu) Received: from mail-svr1.cs.utah.edu (mail-svr1.cs.utah.edu [155.98.64.200]) by mx1.FreeBSD.org (Postfix) with ESMTP id AAFD043D55; Tue, 8 Nov 2005 01:38:01 +0000 (GMT) (envelope-from vaibhave@cs.utah.edu) Received: from localhost (localhost [127.0.0.1]) by mail-svr1.cs.utah.edu (Postfix) with ESMTP id DA366346E0; Mon, 7 Nov 2005 18:38:00 -0700 (MST) Received: from mail-svr1.cs.utah.edu ([127.0.0.1]) by localhost (mail-svr1.cs.utah.edu [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 15215-09; Mon, 7 Nov 2005 18:38:00 -0700 (MST) Received: from trust.cs.utah.edu (trust.cs.utah.edu [155.98.65.28]) by mail-svr1.cs.utah.edu (Postfix) with ESMTP id 816B034692; Mon, 7 Nov 2005 18:38:00 -0700 (MST) Received: by trust.cs.utah.edu (Postfix, from userid 4969) id 754343F71; Mon, 7 Nov 2005 18:38:00 -0700 (MST) Received: from localhost (localhost [127.0.0.1]) by trust.cs.utah.edu (Postfix) with ESMTP id 726BC3F6C; Mon, 7 Nov 2005 18:38:00 -0700 (MST) Date: Mon, 7 Nov 2005 18:38:00 -0700 (MST) From: Vaibhave Agarwal To: John Baldwin In-Reply-To: <200511071105.58729.jhb@freebsd.org> Message-ID: References: <20051027233636.GA39380@dmw.hopto.org> <436E874E.4010305@root.org> <200511071105.58729.jhb@freebsd.org> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Virus-Scanned: amavisd-new at cs.utah.edu Cc: freebsd-net@freebsd.org, freebsd-acpi@freebsd.org, current@freebsd.org, Nate Lawson Subject: Re: Freebsd 6.0 doesnt detect local APIC on a Pentium 3 machine X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Nov 2005 01:38:02 -0000 On Mon, 7 Nov 2005, John Baldwin wrote: > And even then it can't be used for any device interrupts since there aren't > any I/O APICs. On a UP machine without I/O APICs, it's actually probably > more optimal to just use irq0 and irq8 for clocks rather than the lapic timer > anyway. The only real possible gain is the ability to use the profiling > interrupt from the local APIC. I got access to the BIOS of the Pentium 3 machine I am using, but it has no option to enable/disable the local APIC. Joseph Koshy is right, Linux enables the local APIC timer while booting up. I got the following in the bootup log of Linux 2.4 kernel on the same machine. ------------------------- Local APIC disabled by BIOS -- reenabling. Found and enabled local APIC! Using local APIC timer interrupts. calibrating APIC timer ... ------------------------- Though there is no I/O apic in the UP machines, but I only wanted to use local APIC timer in the lapic_timer_oneshot() mode to schedule few timers accurately. thanks vaibhave