cpufreq: intel_pstate: Keep values in aperf/mperf in full precision

Currently we shift right aperf and mperf variables by FRAC_BITS to prevent overflow when we convert them to fix point numbers (shift left by FRAC_BITS). But this is not necessary, because we actually use delta aperf and mperf which are much less than APERF and MPERF values. So, use the unmodified APERF and MPERF values in calculation. This also adds 8 bits in precision, although the gain is insignificant. Signed-off-by: Stratos Karafotis <[email protected]> Signed-off-by: Dirk Brandewie <[email protected]> Signed-off-by: Rafael J. Wysocki <[email protected]>
chewitt · Jul 21, 2014 · ac65813 · ac65813
1 parent 4ab60c3
commit ac65813
Showing 1 changed file with 0 additions and 3 deletions.
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
@@ -584,9 +584,6 @@ static inline void intel_pstate_sample(struct cpudata *cpu)
 	rdmsrl(MSR_IA32_MPERF, mperf);
 	local_irq_restore(flags);
 
-	aperf = aperf >> FRAC_BITS;
-	mperf = mperf >> FRAC_BITS;
-
 	cpu->last_sample_time = cpu->sample.time;
 	cpu->sample.time = ktime_get();
 	cpu->sample.aperf = aperf;