From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S262546AbTKDUwb (ORCPT ); Tue, 4 Nov 2003 15:52:31 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S262558AbTKDUwb (ORCPT ); Tue, 4 Nov 2003 15:52:31 -0500 Received: from 206-158-102-129.prx.blacksburg.ntc-com.net ([206.158.102.129]:55204 "EHLO wombat.ghz.cc") by vger.kernel.org with ESMTP id S262546AbTKDUw2 (ORCPT ); Tue, 4 Nov 2003 15:52:28 -0500 Date: Tue, 4 Nov 2003 15:52:14 -0500 Subject: Re: [PATCH] amd76x_pm on 2.6.0-test9 cleanup Content-Type: text/plain; charset=US-ASCII; format=flowed Mime-Version: 1.0 (Apple Message framework v552) Cc: lkml To: Tony Lindgren From: Charles Lepple In-Reply-To: <20031104200517.GD1042@atomide.com> Message-Id: Content-Transfer-Encoding: 7bit X-Mailer: Apple Mail (2.552) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Tuesday, November 4, 2003, at 03:05 PM, Tony Lindgren wrote: > * Charles Lepple [031104 11:45]: >> On Tuesday 04 November 2003 02:15 pm, Tony Lindgren wrote: >>> I've heard of timing problems if it's compiled in, but supposedly >>> they >>> don't happen when loaded as module. >> >> In some of the earlier testX versions of the kernel, I did not see any >> difference between compiling as a module, and compiling into the >> kernel. (It >> is currently a module on my system.) >> >> I did, however, manage to keep ntpd happy by reducing HZ to 100. Even >> raising >> HZ to 200 is enough to throw off its PLL. The machine is idle for 90% >> of the >> day, though, so I don't know if the PLL is adapting to the fact that >> the >> system is idling, but the values for tick look reasonable. > > Interesting, sounds like the idling causes missed timer interrupts? > Can you > briefly describe what's the easiest way to reproduce the timer > problem, just > change HZ to 200 and look at the system time? At HZ=200, it would take a while to notice. I used adjtimexconfig, which counts the number of kernel ticks which occur in 70 seconds (according to the RTC). The RTC is pretty stable without power management, so I tend to trust it. I think I ended up with a value of tick=11000 (compensation for a 10% slow clock), and if I left the machine idle, ntpd would converge based on the new tick value. Then again, I don't think I tried HZ>=200 on -test9. (When I got Pasi's -test9 patch, I applied it to a -test8-bk kernel with HZ=1000-- I don't remember exactly which one.) Based on his followup email, timekeeping may be better in -test9. I'll check. > I've been using kexec for reboots recently though as the bios reboot > is soo slow. The slowness on my system is supposedly related to ECC initialization, but it's only ~30 seconds for 512MB. Still, if I upgrade the memory, that's a good tip. > But just to verify: 2.6.0-test9 & amd76x_pm as module, and the system > drops > into sleep mode when the module is loaded for the first time until > power is > pressed? And this does not happen after cold reboots or when the > amd76x_pm > is reloaded? Correct. -- Charles Lepple clepple@ghz.cc