sched/cpufreq_sched: add trace events

Trace events will aid in debugging, profiling and tuning.

Signed-off-by: Steve Muckle <smuckle@linaro.org>

include/trace/events/cpufreq_sched.h

@@ -0,0 +1,87 @@
+/*
+ *  Copyright (C)  2015 Steve Muckle <smuckle@linaro.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM cpufreq_sched
+
+#if !defined(_TRACE_CPUFREQ_SCHED_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_CPUFREQ_SCHED_H
+
+#include <linux/sched.h>
+#include <linux/tracepoint.h>
+
+TRACE_EVENT(cpufreq_sched_throttled,
+	    TP_PROTO(unsigned int rem),
+	    TP_ARGS(rem),
+	    TP_STRUCT__entry(
+		    __field(	unsigned int,	rem)
+	    ),
+	    TP_fast_assign(
+		    __entry->rem = rem;
+	    ),
+	    TP_printk("throttled - %d usec remaining", __entry->rem)
+);
+
+TRACE_EVENT(cpufreq_sched_request_opp,
+	    TP_PROTO(int cpu,
+		     unsigned long capacity,
+		     unsigned int freq_new,
+		     unsigned int requested_freq),
+	    TP_ARGS(cpu, capacity, freq_new, requested_freq),
+	    TP_STRUCT__entry(
+		    __field(	int,		cpu)
+		    __field(	unsigned long,	capacity)
+		    __field(	unsigned int,	freq_new)
+		    __field(	unsigned int,	requested_freq)
+		    ),
+	    TP_fast_assign(
+		    __entry->cpu = cpu;
+		    __entry->capacity = capacity;
+		    __entry->freq_new = freq_new;
+		    __entry->requested_freq = requested_freq;
+		    ),
+	    TP_printk("cpu %d cap change, cluster cap request %ld => OPP %d "
+		      "(cur %d)",
+		      __entry->cpu, __entry->capacity, __entry->freq_new,
+		      __entry->requested_freq)
+);
+
+TRACE_EVENT(cpufreq_sched_update_capacity,
+	    TP_PROTO(int cpu,
+		     bool request,
+		     struct sched_capacity_reqs *scr,
+		     unsigned long new_capacity),
+	    TP_ARGS(cpu, request, scr, new_capacity),
+	    TP_STRUCT__entry(
+		    __field(	int,		cpu)
+		    __field(	bool,		request)
+		    __field(	unsigned long,	cfs)
+		    __field(	unsigned long,	rt)
+		    __field(	unsigned long,	dl)
+		    __field(	unsigned long,	total)
+		    __field(	unsigned long,	new_total)
+	    ),
+	    TP_fast_assign(
+		    __entry->cpu = cpu;
+		    __entry->request = request;
+		    __entry->cfs = scr->cfs;
+		    __entry->rt = scr->rt;
+		    __entry->dl = scr->dl;
+		    __entry->total = scr->total;
+		    __entry->new_total = new_capacity;
+	    ),
+	    TP_printk("cpu=%d set_cap=%d cfs=%ld rt=%ld dl=%ld old_tot=%ld "
+		      "new_tot=%ld",
+		      __entry->cpu, __entry->request, __entry->cfs, __entry->rt,
+		      __entry->dl, __entry->total, __entry->new_total)
+);
+
+#endif /* _TRACE_CPUFREQ_SCHED_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>

kernel/sched/cpufreq_sched.c

@@ -14,6 +14,9 @@
 #include <linux/delay.h>
 #include <linux/string.h>
 
+#define CREATE_TRACE_POINTS
+#include <trace/events/cpufreq_sched.h>
+
 #include "sched.h"
 
 #define THROTTLE_NSEC		50000000 /* 50ms default */
@@ -78,6 +81,7 @@ static bool finish_last_request(struct gov_data *gd)
 		int usec_left = ktime_to_ns(ktime_sub(gd->throttle, now));
 
 		usec_left /= NSEC_PER_USEC;
+		trace_cpufreq_sched_throttled(usec_left);
 		usleep_range(usec_left, usec_left + 100);
 		now = ktime_get();
 		if (ktime_after(now, gd->throttle))
@@ -186,6 +190,9 @@ static void update_fdomain_capacity_request(int cpu)
 		goto out;
 	freq_new = policy->freq_table[index_new].frequency;
 
+	trace_cpufreq_sched_request_opp(cpu, capacity, freq_new,
+					gd->requested_freq);
+
 	if (freq_new == gd->requested_freq)
 		goto out;
 
@@ -222,6 +229,8 @@ void update_cpu_capacity_request(int cpu, bool request)
 	if (new_capacity == scr->total)
 		return;
 
+	trace_cpufreq_sched_update_capacity(cpu, request, scr, new_capacity);
+
 	scr->total = new_capacity;
 	if (request)
 		update_fdomain_capacity_request(cpu);