From mboxrd@z Thu Jan 1 00:00:00 1970 From: joe Subject: Re: strange time drift if freq<=50% Date: Sat, 28 Jun 2003 23:49:32 -0400 Sender: cpufreq-admin@www.linux.org.uk Message-ID: <3EFE61CC.3010307@xenotropic.net> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: Errors-To: cpufreq-admin@www.linux.org.uk List-Unsubscribe: , List-Id: List-Post: List-Help: List-Subscribe: , List-Archive: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: cpufreq@www.linux.org.uk Cc: linux@brodo.de I can confirm another case of what Dominik reports here; I don't see any other cases in the archive. I have a Fujitsu Lifebook 2010 with an AMD Athlon-M 1700+, running 2.5.72; if I set the clock to the minimum (via either echo -n "0:63:100:powersave" > /proc/cpufreq or echo "powersave" > /system/devices/system/cpu/cpu0/cpufreq/scaling_governor then I get "repeats" when I hit keys on my keyboard, my fan cranks up to high speed, and it seems like the system clock is running fast. At 63% it seems to work properly. joe Dominik Brodowski wrote (on 4 Jun 2003): On my p4 desktop I see a strange "time drift" if I set the frequency to 50% or below using the p4-clockmod driver.=20 Five runs of "time make" of a previously compiled kernel returned in average the following times: freq: 100% 75% 62.5% 50% time (avg.): 5.9s 7.8s 9.2s 22.5s=09 However, on my wall clock "time make" took only 11s on frequency=3D=3D50%. = If I reduce the frequency even further, pressing any key on the keyboard results in many "repeats" appearing on the screen; and the system time running much too fast. If it's >=3D 62.5%, there's no problem at all. The small patch at the bottom disables all frequency states <62.5% for the p4-clockmod driver until the real cause of this problem can be found. What I'd be interested in is the following, though: does the same bug appear on other cpufreq drivers and architectures? If so, this workaround should be abstracted and moved to a proper place (e.g. kernel/cpufreq.c or drivers/cpufreq/freq_table.c) Dominik