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cpufreq: intel_pstate: Eliminate intel_pstate_get_min_max() 

Some computations in intel_pstate_get_min_max() are not necessary
and one of its two callers doesn't even use the full result.

First off, the fixed-point value of cpu->max_perf represents a
non-negative number between 0 and 1 inclusive and cpu->min_perf
cannot be greater than cpu->max_perf.  It is not necessary to check
those conditions every time the numbers in question are used.

Moreover, since intel_pstate_max_within_limits() only needs the
upper boundary, it doesn't make sense to compute the lower one in
there and returning min and max from intel_pstate_get_min_max()
via pointers doesn't look particularly nice.

For the above reasons, drop intel_pstate_get_min_max(), add a helper
to get the base P-state for min/max computations and carry out them
directly in the previous callers of intel_pstate_get_min_max().

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Rafael J. Wysocki 2017-03-28 00:24:26 +02:00
parent 2bfc4cbb5f
commit b02aabe8ab
1 changed files with 14 additions and 26 deletions
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40
drivers/cpufreq/intel_pstate.c
View File

@ -1496,26 +1496,10 @@ static int knl_get_turbo_pstate(void)
return ret;
}
static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
static int intel_pstate_get_base_pstate(struct cpudata *cpu)
{
int max_perf = cpu->pstate.turbo_pstate;
int max_perf_adj;
int min_perf;
if (global.no_turbo || global.turbo_disabled)
max_perf = cpu->pstate.max_pstate;
/*
* performance can be limited by user through sysfs, by cpufreq
* policy, or by cpu specific default values determined through
* experimentation.
*/
max_perf_adj = fp_ext_toint(max_perf * cpu->max_perf);
*max = clamp_t(int, max_perf_adj,
cpu->pstate.min_pstate, cpu->pstate.turbo_pstate);
min_perf = fp_ext_toint(max_perf * cpu->min_perf);
*min = clamp_t(int, min_perf, cpu->pstate.min_pstate, max_perf);
return global.no_turbo || global.turbo_disabled ?
cpu->pstate.max_pstate : cpu->pstate.turbo_pstate;
}
static void intel_pstate_set_pstate(struct cpudata *cpu, int pstate)
@ -1538,11 +1522,13 @@ static void intel_pstate_set_min_pstate(struct cpudata *cpu)
static void intel_pstate_max_within_limits(struct cpudata *cpu)
{
int min_pstate, max_pstate;
int pstate;
update_turbo_state();
intel_pstate_get_min_max(cpu, &min_pstate, &max_pstate);
intel_pstate_set_pstate(cpu, max_pstate);
pstate = intel_pstate_get_base_pstate(cpu);
pstate = max(cpu->pstate.min_pstate,
fp_ext_toint(pstate * cpu->max_perf));
intel_pstate_set_pstate(cpu, pstate);
}
static void intel_pstate_get_cpu_pstates(struct cpudata *cpu)
@ -1704,11 +1690,13 @@ static inline int32_t get_target_pstate_use_performance(struct cpudata *cpu)
static int intel_pstate_prepare_request(struct cpudata *cpu, int pstate)
{
int max_perf, min_perf;
int max_pstate = intel_pstate_get_base_pstate(cpu);
int min_pstate;
intel_pstate_get_min_max(cpu, &min_perf, &max_perf);
pstate = clamp_t(int, pstate, min_perf, max_perf);
return pstate;
min_pstate = max(cpu->pstate.min_pstate,
fp_ext_toint(max_pstate * cpu->min_perf));
max_pstate = max(min_pstate, fp_ext_toint(max_pstate * cpu->max_perf));
return clamp_t(int, pstate, min_pstate, max_pstate);
}
static void intel_pstate_update_pstate(struct cpudata *cpu, int pstate)