From owner-freebsd-current Sun Feb 11 01:14:01 1996 Return-Path: owner-current Received: (from root@localhost) by freefall.freebsd.org (8.7.3/8.7.3) id BAA22648 for current-outgoing; Sun, 11 Feb 1996 01:14:01 -0800 (PST) Received: from tfs.com (tfs.com [140.145.250.1]) by freefall.freebsd.org (8.7.3/8.7.3) with SMTP id BAA22643 for ; Sun, 11 Feb 1996 01:13:59 -0800 (PST) Received: from critter.tfs.com by tfs.com (smail3.1.28.1) with SMTP id m0tlXr2-0003wPC; Sun, 11 Feb 96 01:13 PST Received: from localhost.tfs.com (localhost.tfs.com [127.0.0.1]) by critter.tfs.com (8.6.12/8.6.12) with SMTP id KAA06071; Sun, 11 Feb 1996 10:14:11 +0100 X-Authentication-Warning: critter.tfs.com: Host localhost.tfs.com didn't use HELO protocol To: Bruce Evans cc: current@freebsd.org Subject: Re: calibrating clocks In-reply-to: Your message of "Sun, 11 Feb 1996 04:52:09 +1100." <199602101752.EAA05969@godzilla.zeta.org.au> Date: Sun, 11 Feb 1996 10:14:10 +0100 Message-ID: <6069.824030050@critter.tfs.com> From: Poul-Henning Kamp Sender: owner-current@freebsd.org Precedence: bulk > I plan to calibrate all the system clocks relative to the MC14618A (RTC) > clock and perhaps use the results automatically. Sample results on a > P133 for a sequence of calibrations run at boot time: Did you see the email about the "almost correct sub-tic" stunt ? Basically you count how many times microtime was called per tick, make a (short) running avg of it, and when people call microtime you just return the tick + a counter times that avg. For most if not all purposes this would be cheap and OK. Actually only high-precision profiling and NTP would need any better... -- Poul-Henning Kamp | phk@FreeBSD.ORG FreeBSD Core-team. http://www.freebsd.org/~phk | phk@login.dknet.dk Private mailbox. whois: [PHK] | phk@ref.tfs.com TRW Financial Systems, Inc. Future will arrive by its own means, progress not so.