Hi, On Wed, Oct 15, 2008 at 10:21 AM, Andrej van der Zee <[EMAIL PROTECTED]> wrote: > Thank you! > > I am sorry for asking, but how can I force the frequencies with sysfs? > I found the following entries in /sys: > > /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq > /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_min_freq > /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq > cur = current frequency min= minimal frequency allowed max = maximal frequency allowed
> /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq > /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq > min = minimal frequency supported max = maximal frequency supported To lock at max frequency, as root do: # cat scaling_max_freq > cpuinfo_min_freq Repeat for each CPU you have. Alternatively, you can install the 'performance' governor. > Only the last two are writable, but changing them does not effect the > first three. I also do not really understand the differences. I hope > you could help me out here. > > Thank you, > Andrej > > > > But I am not allowed to write those from user space. Is t > > On Wed, Oct 15, 2008 at 4:56 PM, stephane eranian > <[EMAIL PROTECTED]> wrote: >> Andrej, >> >> >> On Wed, Oct 15, 2008 at 7:32 AM, Andrej van der Zee >> <[EMAIL PROTECTED]> wrote: >>> Sorry, let me be more specific. Obviously I need the number of cycles >>> per second to convert cycles to seconds. Is it possible to get this >>> value programmatic? And supposedly I have the value, is there anything >>> against using it in a simple formula like: CPU_SEC = MEASURED_CYCLES / >>> CYCLES_PER_SEC. >>> >> You can get the cycles per second from the frequency of the CPU. This >> is available >> in /proc/cpuinfo and expressed in MHz. 1MHz is 1 million cycles per second. >> >> However, you have to be careful with CPU clock speed throttling, i.e., >> varying clock >> frequency based on utilization. To avoid problems, you need to lock the >> speed by >> forcing the min/max frequencies via sysfs. >> > > > > -- > Andrej van der Zee > 2-40-19 Koenji-minami > Suginami-ku, Tokyo > 166-0003 JAPAN > Mobile: 0031-(0)80-65251092 > Phone/Fax: 0031-(0)3-3318-3155 > ------------------------------------------------------------------------- This SF.Net email is sponsored by the Moblin Your Move Developer's challenge Build the coolest Linux based applications with Moblin SDK & win great prizes Grand prize is a trip for two to an Open Source event anywhere in the world http://moblin-contest.org/redirect.php?banner_id=100&url=/ _______________________________________________ perfmon2-devel mailing list perfmon2-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/perfmon2-devel
