From: Lukasz Luba <lukasz.luba@arm.com>
To: linux-kernel@vger.kernel.org
Cc: sudeep.holla@arm.com, dietmar.eggemann@arm.com,
vincent.guittot@linaro.org, gregkh@linuxfoundation.org,
rafael@kernel.org, rostedt@goodmis.org, mingo@redhat.com,
lukasz.luba@arm.com
Subject: [PATCH] arch_topology: Trace the update thermal pressure
Date: Tue, 19 Apr 2022 17:48:01 +0100 [thread overview]
Message-ID: <20220419164801.29078-1-lukasz.luba@arm.com> (raw)
Add trace event to capture the moment of the call for updating the thermal
pressure value. It's helpful to investigate how often those events occurs
in a system dealing with throttling. This trace event is needed since the
old 'cdev_update' might not be used by some drivers. Also, the new trace
event shows capacity value, not a cooling state.
We already have a trace point 'pelt_thermal_tp' which after a change to
trace event can be paired with this new 'thermal_pressure_update' and
derive more insight what is going on in the system under pressure
(and why).
Signed-off-by: Lukasz Luba <lukasz.luba@arm.com>
---
drivers/base/arch_topology.c | 4 ++++
include/trace/events/thermal.h | 19 +++++++++++++++++++
2 files changed, 23 insertions(+)
diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c
index 1d6636ebaac5..4f0392de3081 100644
--- a/drivers/base/arch_topology.c
+++ b/drivers/base/arch_topology.c
@@ -19,6 +19,8 @@
#include <linux/rcupdate.h>
#include <linux/sched.h>
+#include <trace/events/thermal.h>
+
static DEFINE_PER_CPU(struct scale_freq_data __rcu *, sft_data);
static struct cpumask scale_freq_counters_mask;
static bool scale_freq_invariant;
@@ -195,6 +197,8 @@ void topology_update_thermal_pressure(const struct cpumask *cpus,
th_pressure = max_capacity - capacity;
+ trace_thermal_pressure_update(cpu, th_pressure);
+
for_each_cpu(cpu, cpus)
WRITE_ONCE(per_cpu(thermal_pressure, cpu), th_pressure);
}
diff --git a/include/trace/events/thermal.h b/include/trace/events/thermal.h
index 8a5f04888abd..1bf08ee1a25b 100644
--- a/include/trace/events/thermal.h
+++ b/include/trace/events/thermal.h
@@ -65,6 +65,25 @@ TRACE_EVENT(cdev_update,
TP_printk("type=%s target=%lu", __get_str(type), __entry->target)
);
+TRACE_EVENT(thermal_pressure_update,
+
+ TP_PROTO(int cpu, unsigned long thermal_pressure),
+
+ TP_ARGS(cpu, thermal_pressure),
+
+ TP_STRUCT__entry(
+ __field(int, cpu)
+ __field(unsigned long, thermal_pressure)
+ ),
+
+ TP_fast_assign(
+ __entry->cpu = cpu;
+ __entry->thermal_pressure = thermal_pressure;
+ ),
+
+ TP_printk("cpu=%d thermal_pressure=%lu", __entry->cpu, __entry->thermal_pressure)
+);
+
TRACE_EVENT(thermal_zone_trip,
TP_PROTO(struct thermal_zone_device *tz, int trip,
--
2.17.1
next reply other threads:[~2022-04-19 16:54 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-19 16:48 Lukasz Luba [this message]
2022-04-20 8:34 ` [PATCH] arch_topology: Trace the update thermal pressure kernel test robot
2022-04-25 10:05 ` Lukasz Luba
2022-04-20 23:44 ` Steven Rostedt
2022-04-21 6:26 ` Lukasz Luba
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