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cpufreq: intel_pstate: Set P-state upfront in performance mode 

After commit a4675fbc4a (cpufreq: intel_pstate: Replace timers with
utilization update callbacks) the cpufreq governor callbacks may not
be invoked on NOHZ_FULL CPUs and, in particular, switching to the
"performance" policy via sysfs may not have any effect on them.  That
is a problem, because it usually is desirable to squeeze the last
bit of performance out of those CPUs, so work around it by setting
the maximum P-state (within the limits) in intel_pstate_set_policy()
upfront when the policy is CPUFREQ_POLICY_PERFORMANCE.

Fixes: a4675fbc4a (cpufreq: intel_pstate: Replace timers with utilization update callbacks)
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
This commit is contained in:
Rafael J. Wysocki 2016-10-19 02:57:22 +02:00
parent c6fe46a79e
commit a6c6ead141
1 changed files with 25 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

29
drivers/cpufreq/intel_pstate.c
View File

@ -1142,10 +1142,8 @@ static void intel_pstate_get_min_max(struct cpudata *cpu, int *min, int *max)
*min = clamp_t(int, min_perf, cpu->pstate.min_pstate, max_perf);
}
static void intel_pstate_set_min_pstate(struct cpudata *cpu)
static void intel_pstate_set_pstate(struct cpudata *cpu, int pstate)
{
int pstate = cpu->pstate.min_pstate;
trace_cpu_frequency(pstate * cpu->pstate.scaling, cpu->cpu);
cpu->pstate.current_pstate = pstate;
/*
@ -1157,6 +1155,20 @@ static void intel_pstate_set_min_pstate(struct cpudata *cpu)
pstate_funcs.get_val(cpu, pstate));
}
static void intel_pstate_set_min_pstate(struct cpudata *cpu)
{
intel_pstate_set_pstate(cpu, cpu->pstate.min_pstate);
}
static void intel_pstate_max_within_limits(struct cpudata *cpu)
{
int min_pstate, max_pstate;
update_turbo_state();
intel_pstate_get_min_max(cpu, &min_pstate, &max_pstate);
intel_pstate_set_pstate(cpu, max_pstate);
}
static void intel_pstate_get_cpu_pstates(struct cpudata *cpu)
{
cpu->pstate.min_pstate = pstate_funcs.get_min();
@ -1491,7 +1503,7 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy)
pr_debug("set_policy cpuinfo.max %u policy->max %u\n",
policy->cpuinfo.max_freq, policy->max);
cpu = all_cpu_data[0];
cpu = all_cpu_data[policy->cpu];
if (cpu->pstate.max_pstate_physical > cpu->pstate.max_pstate &&
policy->max < policy->cpuinfo.max_freq &&
policy->max > cpu->pstate.max_pstate * cpu->pstate.scaling) {
@ -1535,6 +1547,15 @@ static int intel_pstate_set_policy(struct cpufreq_policy *policy)
limits->max_perf = round_up(limits->max_perf, FRAC_BITS);
out:
if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) {
/*
* NOHZ_FULL CPUs need this as the governor callback may not
* be invoked on them.
*/
intel_pstate_clear_update_util_hook(policy->cpu);
intel_pstate_max_within_limits(cpu);
}
intel_pstate_set_update_util_hook(policy->cpu);
intel_pstate_hwp_set_policy(policy);