| Message ID | c31960d7db67bdf4fc578fa967d4699291879f43.1502701992.git.viresh.kumar@linaro.org (mailing list archive) |
|---|---|
| State | Mainlined |
| Delegated to: | Rafael Wysocki |
| Headers | show |
On Monday, August 14, 2017 11:20:16 AM CEST Viresh Kumar wrote: > The frequency update from the utilization update handlers can be divided > into two parts: > > (A) Finding the next frequency > (B) Updating the frequency > > While any CPU can do (A), (B) can be restricted to a group of CPUs only, > depending on the current platform. > > For platforms where fast cpufreq switching is possible, both (A) and (B) > are always done from the same CPU and that CPU should be capable of > changing the frequency of the target CPU. > > But for platforms where fast cpufreq switching isn't possible, after > doing (A) we wake up a kthread which will eventually do (B). This > kthread is already bound to the right set of CPUs, i.e. only those which > can change the frequency of CPUs of a cpufreq policy. And so any CPU > can actually do (A) in this case, as the frequency is updated from the > right set of CPUs only. > > Check cpufreq_can_do_remote_dvfs() only for the fast switching case. > > Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> > --- > V2: s/policy/sg_policy->policy/, missed updating the commit with local > updates earlier, noticed that just now. > > kernel/sched/cpufreq_schedutil.c | 9 +++++++-- > 1 file changed, 7 insertions(+), 2 deletions(-) > > diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c > index 504d0752f8f2..9209d83ecdcf 100644 > --- a/kernel/sched/cpufreq_schedutil.c > +++ b/kernel/sched/cpufreq_schedutil.c > @@ -84,13 +84,18 @@ static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time) > * > * However, drivers cannot in general deal with cross-cpu > * requests, so while get_next_freq() will work, our > - * sugov_update_commit() call may not. > + * sugov_update_commit() call may not for the fast switching platforms. > * > * Hence stop here for remote requests if they aren't supported > * by the hardware, as calculating the frequency is pointless if > * we cannot in fact act on it. > + * > + * For the slow switching platforms, the kthread is always scheduled on > + * the right set of CPUs and any CPU can find the next frequency and > + * schedule the kthread. > */ > - if (!cpufreq_can_do_remote_dvfs(sg_policy->policy)) > + if (sg_policy->policy->fast_switch_enabled && > + !cpufreq_can_do_remote_dvfs(sg_policy->policy)) > return false; > > if (sg_policy->work_in_progress) > Applied, thanks!
diff --git a/kernel/sched/cpufreq_schedutil.c b/kernel/sched/cpufreq_schedutil.c index 504d0752f8f2..9209d83ecdcf 100644 --- a/kernel/sched/cpufreq_schedutil.c +++ b/kernel/sched/cpufreq_schedutil.c @@ -84,13 +84,18 @@ static bool sugov_should_update_freq(struct sugov_policy *sg_policy, u64 time) * * However, drivers cannot in general deal with cross-cpu * requests, so while get_next_freq() will work, our - * sugov_update_commit() call may not. + * sugov_update_commit() call may not for the fast switching platforms. * * Hence stop here for remote requests if they aren't supported * by the hardware, as calculating the frequency is pointless if * we cannot in fact act on it. + * + * For the slow switching platforms, the kthread is always scheduled on + * the right set of CPUs and any CPU can find the next frequency and + * schedule the kthread. */ - if (!cpufreq_can_do_remote_dvfs(sg_policy->policy)) + if (sg_policy->policy->fast_switch_enabled && + !cpufreq_can_do_remote_dvfs(sg_policy->policy)) return false; if (sg_policy->work_in_progress)
The frequency update from the utilization update handlers can be divided into two parts: (A) Finding the next frequency (B) Updating the frequency While any CPU can do (A), (B) can be restricted to a group of CPUs only, depending on the current platform. For platforms where fast cpufreq switching is possible, both (A) and (B) are always done from the same CPU and that CPU should be capable of changing the frequency of the target CPU. But for platforms where fast cpufreq switching isn't possible, after doing (A) we wake up a kthread which will eventually do (B). This kthread is already bound to the right set of CPUs, i.e. only those which can change the frequency of CPUs of a cpufreq policy. And so any CPU can actually do (A) in this case, as the frequency is updated from the right set of CPUs only. Check cpufreq_can_do_remote_dvfs() only for the fast switching case. Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org> --- V2: s/policy/sg_policy->policy/, missed updating the commit with local updates earlier, noticed that just now. kernel/sched/cpufreq_schedutil.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)