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SubjectRe: bizarre 2.6.8.1 /sys permissions
Date
Dave Jones wrote:
> 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.

Okay, so cpufreq just gives informational values in a table while
/proc/cpuinfo actually reflects the speed of the CPU. Right? That's
good, I thought there was an problem if they were different.

--
-bill davidsen (davidsen@tmr.com)
"The secret to procrastination is to put things off until the
last possible moment - but no longer" -me
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