Re: bizarre 2.6.8.1 /sys permissions

[Dave Jones]

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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