From owner-cvs-all Mon Nov 30 11:20:27 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id LAA00976 for cvs-all-outgoing; Mon, 30 Nov 1998 11:20:27 -0800 (PST) (envelope-from owner-cvs-all@FreeBSD.ORG) Received: from critter.freebsd.dk (critter.freebsd.dk [212.242.40.131]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id LAA00949; Mon, 30 Nov 1998 11:20:21 -0800 (PST) (envelope-from phk@critter.freebsd.dk) Received: from critter.freebsd.dk (localhost [127.0.0.1]) by critter.freebsd.dk (8.9.1/8.8.5) with ESMTP id UAA12992; Mon, 30 Nov 1998 20:19:15 +0100 (CET) To: John Hay cc: cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sys/kern kern_clock.c In-reply-to: Your message of "Sat, 30 Nov 1998 21:02:21 +0200." <199811301902.VAA15840@zibbi.mikom.csir.co.za> Date: Mon, 30 Nov 1998 20:19:15 +0100 Message-ID: <12990.912453555@critter.freebsd.dk> From: Poul-Henning Kamp Sender: owner-cvs-all@FreeBSD.ORG Precedence: bulk In message <199811301902.VAA15840@zibbi.mikom.csir.co.za>, John Hay writes: >> >> > We would *not* use the 82C54's timer registers to >> > actually try to read out the counter at all unless we were running on >> > much older cpu's. >> >> We do just that, unless it is a SMP, in which case we would need to >> synchronize the TSC of the cpus before we can use them. (If only Intel >> hadn't yanked the timer from the IO-APIC!) > >Dave Mills have written code to sync the TSCs on the alphas in Digital >Unix. In principal he (and a guy from Digital) have already agread to >make it available to us, but first he have to get it out of the digital >code without any proprietry pieces comming along. I'm currently discussing this with Dave Mills, because I think that code is overkill. He is using a (software-PLL) to keep them in step, but in reality, I don't think they can diverge if you get them synchronized once. Certainly the i386 cpus generate their cpuclock with a PLL locked to the bus clock, I belive the alpha does the same thing, right ? -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop." "ttyv0" -- What UNIX calls a $20K state-of-the-art, 3D, hi-res color terminal To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message