From: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
The only times when intel_pstate checks the policy set for a given
CPU is the initialization of that CPU and updates of its settings
from cpufreq leading to intel_pstate_set_policy() invocatios.
That is insufficient, however, because intel_pstate uses the same
P-state selection function for all CPUs regardless of the policy
setting for each of them and the P-state limits are shared between
them. Thus if the policy is set to "performance" for a particular
CPU, it may not behave as expected if the cpufreq settings are
changed subsequently for another CPU.
That can be easily demonstrated by writing "performance" to
scaling_governor for all CPUs and then switching it to "powersave"
for one of them in which case all of the CPUs will behave as though
their scaling_governor were "powersave" (even though the policy
still appears to be "performance" for the remaining CPUs).
Fix this problem by modifying intel_pstate_adjust_busy_pstate() to
always set the P-state to the maximum allowed by the current limits
if the policy is set to "performance" for the given CPU.
Signed-off-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
---
drivers/cpufreq/intel_pstate.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)
Index: linux-pm/drivers/cpufreq/intel_pstate.c
===================================================================
--- linux-pm.orig/drivers/cpufreq/intel_pstate.c
+++ linux-pm/drivers/cpufreq/intel_pstate.c
@@ -179,6 +179,7 @@ struct _pid {
/**
* struct cpudata - Per CPU instance data storage
* @cpu: CPU number for this instance data
+ * @policy: CPUFreq policy value
* @update_util: CPUFreq utility callback information
* @update_util_set: CPUFreq utility callback is set
* @iowait_boost: iowait-related boost fraction
@@ -201,6 +202,7 @@ struct _pid {
struct cpudata {
int cpu;
+ unsigned int policy;
struct update_util_data update_util;
bool update_util_set;
@@ -1331,7 +1333,8 @@ static inline void intel_pstate_adjust_b
from = cpu->pstate.current_pstate;
- target_pstate = pstate_funcs.get_target_pstate(cpu);
+ target_pstate = cpu->policy == CPUFREQ_POLICY_PERFORMANCE ?
+ cpu->pstate.turbo_pstate : pstate_funcs.get_target_pstate(cpu);
intel_pstate_update_pstate(cpu, target_pstate);
@@ -1498,6 +1501,8 @@ static int intel_pstate_set_policy(struc
policy->cpuinfo.max_freq, policy->max);
cpu = all_cpu_data[policy->cpu];
+ cpu->policy = policy->policy;
+
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) {
@@ -1505,7 +1510,7 @@ static int intel_pstate_set_policy(struc
policy->max = policy->cpuinfo.max_freq;
}
- if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) {
+ if (cpu->policy == CPUFREQ_POLICY_PERFORMANCE) {
limits = &performance_limits;
if (policy->max >= policy->cpuinfo.max_freq) {
pr_debug("set performance\n");
@@ -1541,7 +1546,7 @@ static int intel_pstate_set_policy(struc
limits->max_perf = round_up(limits->max_perf, FRAC_BITS);
out:
- if (policy->policy == CPUFREQ_POLICY_PERFORMANCE) {
+ if (cpu->policy == CPUFREQ_POLICY_PERFORMANCE) {
/*
* NOHZ_FULL CPUs need this as the governor callback may not
* be invoked on them.
