Starting with kernel 2.6.27.10 I observed sometimes that my ThinkPad T41 stays at CPU frequency of 600 MHz when I run a lot of processes with nice level 3 and few more at 19 - even if I have some foreground jobs which normally force the CPU to go to at 1700 MHz A typical scenario is to compile glibc at a Gentoo system mit "make -j 2" and then run another make job at nice level 0 or try to start firefox (which start time itself is OTOH slow enough even with 1.7 GHz). I can quantify this observation with a quick&dirty command line like : $> time factor 819734028463158891 I would expect a real value of 6-7 seconds and a user value of 5-6 seconds. However when I used it 2 times in a row I got : tfoerste@n22 ~ $ time factor 819734028463158891 819734028463158891: 3 273244676154386297 real 0m51.658s user 0m15.691s sys 0m0.013s tfoerste@n22 ~ $ time factor 819734028463158891 819734028463158891: 3 273244676154386297 real 0m19.136s user 0m6.944s sys 0m0.044s BTW during startup I set : $>echo 1 > /sys/devices/system/cpu/cpu0/cpufreq/ondemand/ignore_nice_load My system: tfoerste@n22 ~ $ uname -a Linux n22 2.6.27-gentoo-r7 #12 Sun Dec 28 18:26:57 CET 2008 i686 Intel(R) Pentium(R) M processor 1700MHz GenuineIntel GNU/Linux The appropriate kernel config values are : tfoerste@n22 ~/devel/wireshark/docbook $ zgrep -e GOV -e FREQ /proc/config.gz | grep -v '#' CONFIG_CPU_FREQ=y CONFIG_CPU_FREQ_TABLE=y CONFIG_CPU_FREQ_STAT=m CONFIG_CPU_FREQ_STAT_DETAILS=y CONFIG_CPU_FREQ_DEFAULT_GOV_ONDEMAND=y CONFIG_CPU_FREQ_GOV_PERFORMANCE=y CONFIG_CPU_FREQ_GOV_POWERSAVE=m CONFIG_CPU_FREQ_GOV_ONDEMAND=y CONFIG_X86_ACPI_CPUFREQ=m CONFIG_CPU_IDLE_GOV_LADDER=y CONFIG_CPU_IDLE_GOV_MENU=y -- MfG/Sincerely Toralf Förster pgp finger print: 7B1A 07F4 EC82 0F90 D4C2 8936 872A E508 7DB6 9DA3
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