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Commit a6c6ead1 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

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



After commit a4675fbc (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: a4675fbc (cpufreq: intel_pstate: Replace timers with utilization update callbacks)
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: default avatarSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
parent c6fe46a7

drivers/cpufreq/intel_pstate.c

+25 −4
Original line number Diff line number Diff line
@@ -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);