From: Rafael J. Wysocki <rafael.j.wyso...@intel.com> After commit a4675fbc4a7a (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: a4675fbc4a7a (cpufreq: intel_pstate: Replace timers with utilization update callbacks) Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com> --- drivers/cpufreq/intel_pstate.c | 29 +++++++++++++++++++++++++---- 1 file changed, 25 insertions(+), 4 deletions(-) Index: linux-pm/drivers/cpufreq/intel_pstate.c =================================================================== --- linux-pm.orig/drivers/cpufreq/intel_pstate.c +++ linux-pm/drivers/cpufreq/intel_pstate.c @@ -1137,10 +1137,8 @@ static void intel_pstate_get_min_max(str *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; /* @@ -1152,6 +1150,20 @@ static void intel_pstate_set_min_pstate( 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(); @@ -1485,7 +1497,7 @@ static int intel_pstate_set_policy(struc 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) { @@ -1529,6 +1541,15 @@ static int intel_pstate_set_policy(struc 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);