From owner-freebsd-current Mon Sep 7 00:40:45 1998 Return-Path: Received: (from majordom@localhost) by hub.freebsd.org (8.8.8/8.8.8) id AAA03944 for freebsd-current-outgoing; Mon, 7 Sep 1998 00:40:45 -0700 (PDT) (envelope-from owner-freebsd-current@FreeBSD.ORG) Received: from word.smith.net.au (castles134.castles.com [208.214.165.134]) by hub.freebsd.org (8.8.8/8.8.8) with ESMTP id AAA03939 for ; Mon, 7 Sep 1998 00:40:42 -0700 (PDT) (envelope-from mike@word.smith.net.au) Received: from word.smith.net.au (LOCALHOST [127.0.0.1]) by word.smith.net.au (8.9.1/8.8.8) with ESMTP id AAA12048; Mon, 7 Sep 1998 00:42:02 -0700 (PDT) (envelope-from mike@word.smith.net.au) Message-Id: <199809070742.AAA12048@word.smith.net.au> X-Mailer: exmh version 2.0.2 2/24/98 To: Poul-Henning Kamp cc: Mike Smith , Thomas Dean , current@FreeBSD.ORG Subject: Re: Dmesg Timecounter Varies In-reply-to: Your message of "Mon, 07 Sep 1998 08:37:07 +0200." <21872.905150227@critter.freebsd.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Mon, 07 Sep 1998 00:42:01 -0700 From: Mike Smith Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > >> > >> Notice the maximum flyer. What causes this variability? > > > >Unexpected execution discontinuities; most often SMI activity. We are > >going to have to discontinue our (ab)use of the TSC simply because it's > >not reliable enough. PC timekeeping *sucks*. > > Ahh, but mind you mike, this is >not< the TSC, this is the i8254 :-( Sorry, I should have kept the two comments separate. We can't use the TSC to improve our resolution on the 8254 (because the 8254 is not stable), as you've pointed out already. Regrettably, none of the new platform standards being promulgated by the Evil Empire seem to suggest any improved timekeeping facilities. 8( -- \\ Sometimes you're ahead, \\ Mike Smith \\ sometimes you're behind. \\ mike@smith.net.au \\ The race is long, and in the \\ msmith@freebsd.org \\ end it's only with yourself. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message