[RFCv5 PATCH 40/46] sched/cpufreq_sched: compute freq_new based on capacity_orig_of()

Morten Rasmussen
2015-07-07T18:56:13Z

From: Juri Lelli <juri.lelli@arm.com>

capacity is both cpu and freq scaled with EAS. We thus need to compute
freq_new using capacity_orig_of(), so that we properly scale back the thing
on heterogeneous architectures. In fact, capacity_orig_of() returns only
the cpu scaled part of capacity (see update_cpu_capacity()). So, to scale
freq_new correctly, we multiply policy->max by capacity/capacity_orig_of()
instead of capacity/1024.

cc: Ingo Molnar <mingo@redhat.com>
cc: Peter Zijlstra <peterz@infradead.org>

Signed-off-by: Juri Lelli <juri.lelli@arm.com>
---
kernel/sched/cpufreq_sched.c | 2 +-
kernel/sched/fair.c | 2 +-
kernel/sched/sched.h | 2 ++
3 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/kernel/sched/cpufreq_sched.c b/kernel/sched/cpufreq_sched.c
index 2968f3a..7071528 100644
--- a/kernel/sched/cpufreq_sched.c
+++ b/kernel/sched/cpufreq_sched.c
@@ -184,7 +184,7 @@ void cpufreq_sched_set_cap(int cpu, unsigned long capacity)
goto out;

/* Convert the new maximum capacity request into a cpu frequency */
- freq_new = capacity * policy->max >> SCHED_CAPACITY_SHIFT;
+ freq_new = (capacity * policy->max) / capacity_orig_of(cpu);

/* No change in frequency? Bail and return current capacity. */
if (freq_new == policy->cur)
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index d395bc9..f74e9d2 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -4625,7 +4625,7 @@ static unsigned long capacity_of(int cpu)
return cpu_rq(cpu)->cpu_capacity;
}

-static unsigned long capacity_orig_of(int cpu)
+unsigned long capacity_orig_of(int cpu)
{
return cpu_rq(cpu)->cpu_capacity_orig;
}
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index b5e27d9..1327dc7 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1476,6 +1476,8 @@ unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
}
#endif

+unsigned long capacity_orig_of(int cpu);
+
extern struct static_key __sched_energy_freq;
static inline bool sched_energy_freq(void)
{
--
1.9.1