linux-kernel - [PATCH 05/17] trace: energy_model: Add trace event for EM runtime modifications

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Message-Id: <20230314103357.26010-6-lukasz.luba@arm.com>
Date:   Tue, 14 Mar 2023 10:33:45 +0000
From:   Lukasz Luba <lukasz.luba@....com>
To:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
        rafael@...nel.org
Cc:     lukasz.luba@....com, dietmar.eggemann@....com, rui.zhang@...el.com,
        amit.kucheria@...durent.com, amit.kachhap@...il.com,
        daniel.lezcano@...aro.org, viresh.kumar@...aro.org,
        len.brown@...el.com, pavel@....cz, Pierre.Gondois@....com,
        ionela.voinescu@....com, rostedt@...dmis.org, mhiramat@...nel.org
Subject: [PATCH 05/17] trace: energy_model: Add trace event for EM runtime modifications

The Energy Model (EM) supports runtime modifications. Track the changes
in order to do post-processing analysis. Don't use arrays in the trace
event, since they are not properly supported by the tools. Instead use
simple "unroll" with emitting the trace event for each EM array entry
with proper ID information. The older debugging mechanism which was
the simple debugfs which dumping the EM content won't be sufficient for
the modifiable EM purpose. This trace event mechanism would address the
needs.

Signed-off-by: Lukasz Luba <lukasz.luba@....com>
---
 include/trace/events/energy_model.h | 46 +++++++++++++++++++++++++++++
 kernel/power/energy_model.c         |  3 ++
 2 files changed, 49 insertions(+)
 create mode 100644 include/trace/events/energy_model.h

diff --git a/include/trace/events/energy_model.h b/include/trace/events/energy_model.h
new file mode 100644
index 000000000000..f70babeb5dde
--- /dev/null
+++ b/include/trace/events/energy_model.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM energy_model
+
+#if !defined(_TRACE_ENERGY_MODEL_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_ENERGY_MODEL_H
+
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(em_perf_state,
+	TP_PROTO(const char *dev_name, int nr_perf_states, int state,
+		 unsigned long ps_frequency, unsigned long ps_power,
+		 unsigned long ps_cost, unsigned long ps_flags),
+
+	TP_ARGS(dev_name, nr_perf_states, state, ps_frequency, ps_power, ps_cost,
+		ps_flags),
+
+	TP_STRUCT__entry(
+		__string(name, dev_name)
+		__field(int, num_states)
+		__field(int, state)
+		__field(unsigned long, frequency)
+		__field(unsigned long, power)
+		__field(unsigned long, cost)
+		__field(unsigned long, flags)
+	),
+
+	TP_fast_assign(
+		__assign_str(name, dev_name);
+		__entry->num_states = nr_perf_states;
+		__entry->state = state;
+		__entry->frequency = ps_frequency;
+		__entry->power = ps_power;
+		__entry->cost = ps_cost;
+		__entry->flags = ps_flags;
+	),
+
+	TP_printk("dev_name=%s nr_perf_states=%d state=%d frequency=%lu power=%lu cost=%lu flags=%lu",
+		__get_str(name), __entry->num_states, __entry->state,
+		__entry->frequency, __entry->power, __entry->cost,
+		__entry->flags)
+);
+#endif /* _TRACE_ENERGY_MODEL_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/kernel/power/energy_model.c b/kernel/power/energy_model.c
index 937e98a71ed5..3b778743ba89 100644
--- a/kernel/power/energy_model.c
+++ b/kernel/power/energy_model.c
@@ -17,6 +17,9 @@
 #include <linux/sched/topology.h>
 #include <linux/slab.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/energy_model.h>
+
 /*
  * Mutex serializing the registrations of performance domains and letting
  * callbacks defined by drivers sleep.
-- 
2.17.1