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intel_pstate: Optimize calculation for max/min_perf_adj

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mul_fp(int_tofp(A), B) expands to:
((A << FRAC_BITS) * B) >> FRAC_BITS, so the same result can be obtained
via simple multiplication A * B.  Apply this observation to
max_perf * limits->max_perf and max_perf * limits->min_perf in
intel_pstate_get_min_max()."

Signed-off-by: Philippe Longepe <philippe.longepe@linux.intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Philippe Longepe 2016-03-06 08:34:04 +01:00 committed by Rafael J. Wysocki
parent b54a0dfd56
commit a158bed5dc
1 changed files with 2 additions and 2 deletions
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4
drivers/cpufreq/intel_pstate.c
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@ -831,11 +831,11 @@ static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
* policy, or by cpu specific default values determined through
* experimentation.
*/
max_perf_adj = fp_toint(mul_fp(int_tofp(max_perf), limits->max_perf));
max_perf_adj = fp_toint(max_perf * limits->max_perf);
*max = clamp_t(int, max_perf_adj,
cpu->pstate.min_pstate, cpu->pstate.turbo_pstate);
min_perf = fp_toint(mul_fp(int_tofp(max_perf), limits->min_perf));
min_perf = fp_toint(max_perf * limits->min_perf);
*min = clamp_t(int, min_perf, cpu->pstate.min_pstate, max_perf);
}