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authorThara Gopinath <thara.gopinath@linaro.org>2020-02-21 19:52:05 -0500
committerIngo Molnar <mingo@kernel.org>2020-03-06 12:57:17 +0100
commit765047932f153265db6ef15be208d6cbfc03dc62 (patch)
tree49fd26bb4ce13c8af9bbdde8bf4ce9ed70f62565 /kernel/sched
parentf1dfdab694eb3838ac26f4b73695929c07d92a33 (diff)
downloadlinux-765047932f153265db6ef15be208d6cbfc03dc62.tar.bz2
sched/pelt: Add support to track thermal pressure
Extrapolating on the existing framework to track rt/dl utilization using pelt signals, add a similar mechanism to track thermal pressure. The difference here from rt/dl utilization tracking is that, instead of tracking time spent by a CPU running a RT/DL task through util_avg, the average thermal pressure is tracked through load_avg. This is because thermal pressure signal is weighted time "delta" capacity unlike util_avg which is binary. "delta capacity" here means delta between the actual capacity of a CPU and the decreased capacity a CPU due to a thermal event. In order to track average thermal pressure, a new sched_avg variable avg_thermal is introduced. Function update_thermal_load_avg can be called to do the periodic bookkeeping (accumulate, decay and average) of the thermal pressure. Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org> Signed-off-by: Thara Gopinath <thara.gopinath@linaro.org> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Link: https://lkml.kernel.org/r/20200222005213.3873-2-thara.gopinath@linaro.org
Diffstat (limited to 'kernel/sched')
-rw-r--r--kernel/sched/pelt.c31
-rw-r--r--kernel/sched/pelt.h31
-rw-r--r--kernel/sched/sched.h3
3 files changed, 65 insertions, 0 deletions
diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c
index c40d57a2a248..b647d04d9c8b 100644
--- a/kernel/sched/pelt.c
+++ b/kernel/sched/pelt.c
@@ -368,6 +368,37 @@ int update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
return 0;
}
+#ifdef CONFIG_SCHED_THERMAL_PRESSURE
+/*
+ * thermal:
+ *
+ * load_sum = \Sum se->avg.load_sum but se->avg.load_sum is not tracked
+ *
+ * util_avg and runnable_load_avg are not supported and meaningless.
+ *
+ * Unlike rt/dl utilization tracking that track time spent by a cpu
+ * running a rt/dl task through util_avg, the average thermal pressure is
+ * tracked through load_avg. This is because thermal pressure signal is
+ * time weighted "delta" capacity unlike util_avg which is binary.
+ * "delta capacity" = actual capacity -
+ * capped capacity a cpu due to a thermal event.
+ */
+
+int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
+{
+ if (___update_load_sum(now, &rq->avg_thermal,
+ capacity,
+ capacity,
+ capacity)) {
+ ___update_load_avg(&rq->avg_thermal, 1);
+ trace_pelt_thermal_tp(rq);
+ return 1;
+ }
+
+ return 0;
+}
+#endif
+
#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
/*
* irq:
diff --git a/kernel/sched/pelt.h b/kernel/sched/pelt.h
index afff644da065..eb034d9f024d 100644
--- a/kernel/sched/pelt.h
+++ b/kernel/sched/pelt.h
@@ -7,6 +7,26 @@ int __update_load_avg_cfs_rq(u64 now, struct cfs_rq *cfs_rq);
int update_rt_rq_load_avg(u64 now, struct rq *rq, int running);
int update_dl_rq_load_avg(u64 now, struct rq *rq, int running);
+#ifdef CONFIG_SCHED_THERMAL_PRESSURE
+int update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity);
+
+static inline u64 thermal_load_avg(struct rq *rq)
+{
+ return READ_ONCE(rq->avg_thermal.load_avg);
+}
+#else
+static inline int
+update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
+{
+ return 0;
+}
+
+static inline u64 thermal_load_avg(struct rq *rq)
+{
+ return 0;
+}
+#endif
+
#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
int update_irq_load_avg(struct rq *rq, u64 running);
#else
@@ -159,6 +179,17 @@ update_dl_rq_load_avg(u64 now, struct rq *rq, int running)
}
static inline int
+update_thermal_load_avg(u64 now, struct rq *rq, u64 capacity)
+{
+ return 0;
+}
+
+static inline u64 thermal_load_avg(struct rq *rq)
+{
+ return 0;
+}
+
+static inline int
update_irq_load_avg(struct rq *rq, u64 running)
{
return 0;
diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 2a0caf394dd4..6c839f829a25 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -961,6 +961,9 @@ struct rq {
#ifdef CONFIG_HAVE_SCHED_AVG_IRQ
struct sched_avg avg_irq;
#endif
+#ifdef CONFIG_SCHED_THERMAL_PRESSURE
+ struct sched_avg avg_thermal;
+#endif
u64 idle_stamp;
u64 avg_idle;