Messages in this thread |  | | | Date | Tue, 23 Mar 2010 15:41:52 +0100 | | From | Dominik Brodowski <> | | Subject | Re: [PATCH 5/5] cpufreq: Add support for actual freq |
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Hey,
On Tue, Mar 23, 2010 at 03:23:49PM +0100, Borislav Petkov wrote: > > scaling_cur freq should show the frequency the kernel/cpufreq > > subsystem thinks it's in. > > Well, we have also > /sys/devices/system/cpu/cpu<NUM>/cpufreq/cpuinfo_cur_freq and it reads > also policy->cur.
No. cpuinfo_cur_freq calls __cpufreq_get() which itself calls the driver's ->get() callback, which is exactly for determining the current frequency. I assume CPUFREQ_CONST_LOOP is set, else we'd get into trouble; but as long as that's the case I see no problem in using ->get() / cpuinfo_cur_freq to read out the current actual frequency.
> Why not show the actual frequency in scaling_cur_freq then?
Quoting Documentation/cpu-freq/user-guide.txt :
cpuinfo_cur_freq : Current frequency of the CPU as obtained from the hardware, in KHz. This is the frequency the CPU actually runs at.
scaling_cur_freq : Current frequency of the CPU as determined by the governor and cpufreq core, in KHz. This is the frequency the kernel thinks the CPU runs at.
So scaling_cur_freq may not be mis-used for this; cpuinfo_cur_freq may be used for it, though. IMVHO.
Best, Dominik
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