| Message ID | 20210610150324.22919-2-lukasz.luba@arm.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add allowed CPU capacity knowledge to EAS | expand |
On 10-06-21, 16:03, Lukasz Luba wrote: > The thermal pressure signal gives information to the scheduler about > reduced CPU capacity due to thermal. It is based on a value stored in a > per-cpu 'thermal_pressure' variable. The online CPUs will get the new > value there, while the offline won't. Unfortunately, when the CPU is back > online, the value read from per-cpu variable might be wrong (stale data). > This might affect the scheduler decisions, since it sees the CPU capacity > differently than what is actually available. > > Fix it by making sure that all online+offline CPUs would get the proper > value in their per-cpu variable when thermal framework sets capping. > > Fixes: f12e4f66ab6a3 ("thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping") > Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> > --- > drivers/thermal/cpufreq_cooling.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c > index eeb4e4b76c0b..43b1ae8a7789 100644 > --- a/drivers/thermal/cpufreq_cooling.c > +++ b/drivers/thermal/cpufreq_cooling.c > @@ -478,7 +478,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, > ret = freq_qos_update_request(&cpufreq_cdev->qos_req, frequency); > if (ret >= 0) { > cpufreq_cdev->cpufreq_state = state; > - cpus = cpufreq_cdev->policy->cpus; > + cpus = cpufreq_cdev->policy->related_cpus; > max_capacity = arch_scale_cpu_capacity(cpumask_first(cpus)); > capacity = frequency * max_capacity; > capacity /= cpufreq_cdev->policy->cpuinfo.max_freq; Acked-by: Viresh Kumar <viresh.kumar@linaro.org> -- viresh
On 6/14/21 11:12 AM, Viresh Kumar wrote: > On 10-06-21, 16:03, Lukasz Luba wrote: >> The thermal pressure signal gives information to the scheduler about >> reduced CPU capacity due to thermal. It is based on a value stored in a >> per-cpu 'thermal_pressure' variable. The online CPUs will get the new >> value there, while the offline won't. Unfortunately, when the CPU is back >> online, the value read from per-cpu variable might be wrong (stale data). >> This might affect the scheduler decisions, since it sees the CPU capacity >> differently than what is actually available. >> >> Fix it by making sure that all online+offline CPUs would get the proper >> value in their per-cpu variable when thermal framework sets capping. >> >> Fixes: f12e4f66ab6a3 ("thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping") >> Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> >> --- >> drivers/thermal/cpufreq_cooling.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c >> index eeb4e4b76c0b..43b1ae8a7789 100644 >> --- a/drivers/thermal/cpufreq_cooling.c >> +++ b/drivers/thermal/cpufreq_cooling.c >> @@ -478,7 +478,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, >> ret = freq_qos_update_request(&cpufreq_cdev->qos_req, frequency); >> if (ret >= 0) { >> cpufreq_cdev->cpufreq_state = state; >> - cpus = cpufreq_cdev->policy->cpus; >> + cpus = cpufreq_cdev->policy->related_cpus; >> max_capacity = arch_scale_cpu_capacity(cpumask_first(cpus)); >> capacity = frequency * max_capacity; >> capacity /= cpufreq_cdev->policy->cpuinfo.max_freq; > > Acked-by: Viresh Kumar <viresh.kumar@linaro.org> > Thank you Viresh! Regards, Lukasz
diff --git a/drivers/thermal/cpufreq_cooling.c b/drivers/thermal/cpufreq_cooling.c index eeb4e4b76c0b..43b1ae8a7789 100644 --- a/drivers/thermal/cpufreq_cooling.c +++ b/drivers/thermal/cpufreq_cooling.c @@ -478,7 +478,7 @@ static int cpufreq_set_cur_state(struct thermal_cooling_device *cdev, ret = freq_qos_update_request(&cpufreq_cdev->qos_req, frequency); if (ret >= 0) { cpufreq_cdev->cpufreq_state = state; - cpus = cpufreq_cdev->policy->cpus; + cpus = cpufreq_cdev->policy->related_cpus; max_capacity = arch_scale_cpu_capacity(cpumask_first(cpus)); capacity = frequency * max_capacity; capacity /= cpufreq_cdev->policy->cpuinfo.max_freq;
The thermal pressure signal gives information to the scheduler about reduced CPU capacity due to thermal. It is based on a value stored in a per-cpu 'thermal_pressure' variable. The online CPUs will get the new value there, while the offline won't. Unfortunately, when the CPU is back online, the value read from per-cpu variable might be wrong (stale data). This might affect the scheduler decisions, since it sees the CPU capacity differently than what is actually available. Fix it by making sure that all online+offline CPUs would get the proper value in their per-cpu variable when thermal framework sets capping. Fixes: f12e4f66ab6a3 ("thermal/cpu-cooling: Update thermal pressure in case of a maximum frequency capping") Signed-off-by: Lukasz Luba <lukasz.luba@arm.com> --- drivers/thermal/cpufreq_cooling.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)