What should cpuinfo_cur_freq mean?

[Andy Lutomirski]

There are least three choices for what the "current frequency" is:

 1. The frequency that the cpufreq driver thinks it has requested.
This shows up in scaling_cur_freq.

 2. The frequency that is actually programmed into the CPU.  This is
what acpi_cpufreq's cpuinfo_cur_freq reports.

 3. A measurement of the number of cycles per unit time that are
currently or recently happening.  This is what intel_pstate reports.

The fact that acpi-cpufreq and intel_pstate behave differently here is
unfortunate.  I have servers [1] with broken BIOS that occasionally
screw up the requested P-state (i.e. MSR 0x199).  With acpi_cpufreq
loaded, I can at least tell that there's a problem by reading
cpuinfo_cur_freq.  With intel_pstate loaded, I get a rapidly
fluctuating value that depends on Turbo's current mood.

Can we separate out these concepts into separate sysfs files?

[1] These are fully up-to-date, recent generation Dell servers.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/