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authorDietmar Eggemann <dietmar.eggemann@arm.com>2017-09-26 19:41:10 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-10-03 03:37:53 +0300
commit0e27c567d1673137b06aa96bb7aef635fb657dee (patch)
treebcbb7041ef1af0a73336595a4e9d72ec5fedb813 /drivers/base
parent400ec74d3b3784a48b09db9518aa2c4b6d4e497f (diff)
downloadlinux-0e27c567d1673137b06aa96bb7aef635fb657dee.tar.xz
drivers base/arch_topology: provide frequency-invariant accounting support
Implements the arch-specific (arm and arm64) frequency-invariance setter function arch_set_freq_scale() which provides the following frequency scaling factor: current_freq(cpu) << SCHED_CAPACITY_SHIFT / max_supported_freq(cpu) One possible consumer of the frequency-invariance getter function topology_get_freq_scale() is the Per-Entity Load Tracking (PELT) mechanism of the task scheduler. Allow inlining of topology_get_freq_scale() into the task scheduler fast path (e.g. __update_load_avg_se()) by coding it as a static inline function in the arch topology header file. Signed-off-by: Dietmar Eggemann <dietmar.eggemann@arm.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/base')
-rw-r--r--drivers/base/arch_topology.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index e9bb368f32b3..416ec2f5211d 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -22,6 +22,20 @@
#include <linux/string.h>
#include <linux/sched/topology.h>
+DEFINE_PER_CPU(unsigned long, freq_scale) = SCHED_CAPACITY_SCALE;
+
+void arch_set_freq_scale(struct cpumask *cpus, unsigned long cur_freq,
+ unsigned long max_freq)
+{
+ unsigned long scale;
+ int i;
+
+ scale = (cur_freq << SCHED_CAPACITY_SHIFT) / max_freq;
+
+ for_each_cpu(i, cpus)
+ per_cpu(freq_scale, i) = scale;
+}
+
static DEFINE_MUTEX(cpu_scale_mutex);
static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;