From owner-freebsd-alpha Tue Nov 12 14:43:35 2002 Delivered-To: freebsd-alpha@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 8F6BA37B401; Tue, 12 Nov 2002 14:43:34 -0800 (PST) Received: from harrier.mail.pas.earthlink.net (harrier.mail.pas.earthlink.net [207.217.120.12]) by mx1.FreeBSD.org (Postfix) with ESMTP id 2F8CC43E75; Tue, 12 Nov 2002 14:43:34 -0800 (PST) (envelope-from tlambert2@mindspring.com) Received: from pool0050.cvx22-bradley.dialup.earthlink.net ([209.179.198.50] helo=mindspring.com) by harrier.mail.pas.earthlink.net with esmtp (Exim 3.33 #1) id 18BjYu-0002SS-00; Tue, 12 Nov 2002 14:31:12 -0800 Message-ID: <3DD180E3.80D3C4F6@mindspring.com> Date: Tue, 12 Nov 2002 14:29:55 -0800 From: Terry Lambert X-Mailer: Mozilla 4.79 [en] (Win98; U) X-Accept-Language: en MIME-Version: 1.0 To: John Baldwin Cc: "Michael A. Mackey" , freebsd-alpha@freebsd.org Subject: Re: Extreme time drift in SMP mode References: Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk List-ID: List-Archive: (Web Archive) List-Help: (List Instructions) List-Subscribe: List-Unsubscribe: X-Loop: FreeBSD.org John Baldwin wrote: > On 12-Nov-2002 Michael A. Mackey wrote: > > Well, I guess I got really lucky.... > > > > I seem to have fixed the time drift problem, based on a hunch. > > > > Drew, after what you said about the boot processor alone driving the > > timing, I decided to allow both processors to drive the timer. So, I > > changed the code in the function 'alpha_clock_interrupt ()' in > > /usr/src/sys/alpha/alpha/interrupt.c (actually I only added an #undef > > SMP statement on line 467 and redefined it before the 'critical_exit()' > > call). > > > > And now, the SMP system keeps proper track of the time. > > > > In a couple of days, I have two more processors arriving. Then I can > > really test if this fix works. > > > > Thanks for your help - and I hope others can verify my results. > > Well, that's not really an ideal fix for the problem. :( Adjusting > the timer frequency in the SMP case instead would be preferred. What if that's just a statistical fix, having to do with interrupt delivery, rather than a real fix? -- Terry To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message