Messages in this thread | | | Date | Thu, 26 Aug 2004 01:48:57 +0100 | From | Dave Jones <> | Subject | Re: bizarre 2.6.8.1 /sys permissions |
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On Wed, Aug 25, 2004 at 04:31:50PM -0700, Dan Hollis wrote: > > > $ cat /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq > > > cat: /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_cur_freq: Permission denied > > Reading this file causes reads from hardware on some cpufreq drivers. > > This can be a slow operation, so a user could degrade system performance > > for everyone else by repeatedly cat'ing it. > > any reason why cpuinfo_cur_freq cant read cpu_khz ?
cpufreq_cur_freq will be one of scaling_available_frequencies. These are usually a value such as 1300MHz, where cpu_mhz is a 'measured' value and will look something like 1303.852
the values cpufreq uses are the values either returned by the hardware as its settable states, or from BIOS tables defining those states.
> or rather, is there any reason why cpuinfo_cur_freq and /proc/cpuinfo > should legitimately differ?
They aren't identical, and serve different purposes.
Dave
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