From mboxrd@z Thu Jan 1 00:00:00 1970 From: Len Brown Subject: Re: cpufreq stops working after a while Date: Wed, 16 Aug 2006 15:28:24 -0400 Message-ID: <200608161528.25238.len.brown@intel.com> References: Reply-To: Len Brown Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Content-Disposition: inline List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: cpufreq-bounces@lists.linux.org.uk Errors-To: cpufreq-bounces+glkc-cpufreq=m.gmane.org+glkc-cpufreq=m.gmane.org@lists.linux.org.uk Content-Type: text/plain; charset="us-ascii" To: cpufreq@lists.linux.org.uk > >I have the same problem. My laptop is Dell Latitude D600 (Intel(R) > >Pentium(R) M processor 1.60GHz). If I'm compiling something, for > >example, that takes a long time, scaling_max_freq is set to 600000 (the > >lowest). If I try to echo 1600000 to scaling_max_freq it do nothing. > >Only after some time if the cpu load is not high I can echoing 1600000 > >again and it works without need to reboot. > > > > Looks like you have the same problem that Mark had in this original thread. Thermal. > It is not a bug in cpufreq. Just that due to cpu load, system is getting heated up and platform decides to reduce the temperature using passive cooling and as a result reduces the frequency. Does your system have active cooling (fans) or does it allow only passive cooling? You can monitor the temperature by looking at stuff under /proc/acpi/termal_zone/*/*. I've got a D600 and have noticed thermal throttling also. The way I noticed it is because bltk showed poor performance compared to other similar laptops when measuring battery life: http://sourceforge.net/projects/bltk I found that this was independent of cpufreq, and would still happen even if the performance governor was used. Sometimes I noticed that the T-state in /proc/acpi/processor/*/throttling was not 0, which was unexpected. I blamed SuSE's stupid powersavd at the time (IIR, it was SL10.1) , but maybe that wasn't the root cause. -Len