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authorQuentin Perret <quentin.perret@arm.com>2018-12-03 09:56:21 +0000
committerIngo Molnar <mingo@kernel.org>2018-12-11 15:17:00 +0100
commit531b5c9f5cd05ead53324f419b32685a22eebe8b (patch)
tree4611a0ddcdbec5c7dbaab6428c129d77b474c51c /drivers/cpufreq
parentb68a4c0dba3b1e1dda1ede49f3c2fc72d3b54567 (diff)
downloadlinux-531b5c9f5cd05ead53324f419b32685a22eebe8b.tar.bz2
sched/topology: Make Energy Aware Scheduling depend on schedutil
Energy Aware Scheduling (EAS) is designed with the assumption that frequencies of CPUs follow their utilization value. When using a CPUFreq governor other than schedutil, the chances of this assumption being true are small, if any. When schedutil is being used, EAS' predictions are at least consistent with the frequency requests. Although those requests have no guarantees to be honored by the hardware, they should at least guide DVFS in the right direction and provide some hope in regards to the EAS model being accurate. To make sure EAS is only used in a sane configuration, create a strong dependency on schedutil being used. Since having sugov compiled-in does not provide that guarantee, make CPUFreq call a scheduler function on governor changes hence letting it rebuild the scheduling domains, check the governors of the online CPUs, and enable/disable EAS accordingly. Signed-off-by: Quentin Perret <quentin.perret@arm.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rjw@rjwysocki.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: adharmap@codeaurora.org Cc: chris.redpath@arm.com Cc: currojerez@riseup.net Cc: dietmar.eggemann@arm.com Cc: edubezval@gmail.com Cc: gregkh@linuxfoundation.org Cc: javi.merino@kernel.org Cc: joel@joelfernandes.org Cc: juri.lelli@redhat.com Cc: morten.rasmussen@arm.com Cc: patrick.bellasi@arm.com Cc: pkondeti@codeaurora.org Cc: skannan@codeaurora.org Cc: smuckle@google.com Cc: srinivas.pandruvada@linux.intel.com Cc: thara.gopinath@linaro.org Cc: tkjos@google.com Cc: valentin.schneider@arm.com Cc: vincent.guittot@linaro.org Cc: viresh.kumar@linaro.org Link: https://lkml.kernel.org/r/20181203095628.11858-9-quentin.perret@arm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/cpufreq.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 7aa3dcad2175..6f23ebb395f1 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -2277,6 +2277,7 @@ static int cpufreq_set_policy(struct cpufreq_policy *policy,
ret = cpufreq_start_governor(policy);
if (!ret) {
pr_debug("cpufreq: governor change\n");
+ sched_cpufreq_governor_change(policy, old_gov);
return 0;
}
cpufreq_exit_governor(policy);