From owner-freebsd-current Fri Oct 6 15:32:55 2000 Delivered-To: freebsd-current@freebsd.org Received: from pike.osd.bsdi.com (pike.osd.bsdi.com [204.216.28.222]) by hub.freebsd.org (Postfix) with ESMTP id 01E7237B503 for ; Fri, 6 Oct 2000 15:32:53 -0700 (PDT) Received: from laptop.baldwin.cx (ether.osd.bsdi.com [204.216.28.196]) by pike.osd.bsdi.com (8.11.0/8.9.3) with ESMTP id e96MVwi55328; Fri, 6 Oct 2000 15:31:58 -0700 (PDT) (envelope-from jhb@FreeBSD.org) Message-ID: X-Mailer: XFMail 1.4.0 on FreeBSD X-Priority: 3 (Normal) Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 8bit MIME-Version: 1.0 In-Reply-To: <200010062217.BGO31522@burka.carrier.kiev.ua> Date: Fri, 06 Oct 2000 15:32:15 -0700 (PDT) From: John Baldwin To: (Valentin Nechayev) Subject: Re: microuptime() went backwards Cc: freebsd-current@FreeBSD.org Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On 06-Oct-00 Valentin Nechayev wrote: > At Fri, 6 Oct 2000 22:00:23 +0000 (UTC), jhb wrote: > > JB> The problem was that the interrupt threads for the clk interrupt > introduced > JB> enough latency that occasionally (mostly during a heavy load of > interrupts) > JB> tc_windup() wasn't called soon enough to update the timecounter. Making > > On my system _each_ boot causes hundreds of these messages. > And as described, long offsets without updating are caused by some > code in drivers, i.e. DELAY(1000000) in isa/fd.c. Is it nesessary to call > tc_windup() between iterations in isa_configure? ;| Yes, I know. The problem didn't occur as badly on SMP systems as the clk ithread didn't suffer from as much latency in that case, but on UP systems it could be quite bad. I used to get it both during boot and when doing things like starting up X. > JB> clock interrupts not be threaded fixes this problem. > > Oh, well, I understand now that scheduling is nesessary to be run early > because interrupts are implemented as kernel threads even when kernel > is in phase of hardware detection.;( This is not done yet. It is something that is on the todo list though (to move SI_SUB_INIT_CLOCKS earlier, basically). > /netch -- John Baldwin -- http://www.FreeBSD.org/~jhb/ PGP Key: http://www.baldwin.cx/~john/pgpkey.asc "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message