aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorDave Martin <dave.martin@linaro.org>2012-05-14 17:40:07 +0100
committerNicolas Pitre <nicolas.pitre@linaro.org>2013-05-13 19:03:40 -0400
commitcc943eda78d22a16b852c69ecb370f45d5d34999 (patch)
tree56e74b011b927e69887988e2f4b95c7e8b522e2f
parent70af94ab7201a6f3cdb5694e9464fa4b054bd8e3 (diff)
downloadvexpress-lsk-cc943eda78d22a16b852c69ecb370f45d5d34999.tar.gz
ARM: bL_switcher: Basic trace events support
This patch adds simple trace events to the b.L switcher code to allow tracing of CPU migration events. To make use of the trace events, you will need: CONFIG_FTRACE=y CONFIG_ENABLE_DEFAULT_TRACERS=y The following events are added: * power:cpu_migrate_begin * power:cpu_migrate_finish each with the following data: u64 timestamp; u32 cpu_hwid; power:cpu_migrate_begin occurs immediately before the switcher-specific migration operations start. power:cpu_migrate_finish occurs immediately when migration is completed. The cpu_hwid field contains the ID fields of the MPIDR. * For power:cpu_migrate_begin, cpu_hwid is the ID of the outbound physical CPU (equivalent to (from_phys_cpu,from_phys_cluster)). * For power:cpu_migrate_finish, cpu_hwid is the ID of the inbound physical CPU (equivalent to (to_phys_cpu,to_phys_cluster)). By design, the cpu_hwid field is masked in the same way as the device tree cpu node reg property, allowing direct correlation to the DT description of the hardware. The timestamp is added in order to minimise timing noise. An accurate system-wide clock should be used for generating this (hopefully getnstimeofday is appropriate, but it could be changed). It could be any monotonic shared clock, since the aim is to allow accurate deltas to be computed. We don't necessarily care about accurate synchronisation with wall clock time. In practice, each switch takes place on a single logical CPU, and the trace infrastructure should guarantee that events are well-ordered with respect to a single logical CPU. Signed-off-by: Dave Martin <dave.martin@linaro.org> Signed-off-by: Nicolas Pitre <nico@linaro.org>
-rw-r--r--arch/arm/common/bL_switcher.c17
-rw-r--r--include/trace/events/power_cpu_migrate.h66
2 files changed, 83 insertions, 0 deletions
diff --git a/arch/arm/common/bL_switcher.c b/arch/arm/common/bL_switcher.c
index e55b55170be..fd59d58fe28 100644
--- a/arch/arm/common/bL_switcher.c
+++ b/arch/arm/common/bL_switcher.c
@@ -19,6 +19,7 @@
#include <linux/cpumask.h>
#include <linux/kthread.h>
#include <linux/wait.h>
+#include <linux/time.h>
#include <linux/clockchips.h>
#include <linux/hrtimer.h>
#include <linux/tick.h>
@@ -32,10 +33,14 @@
#include <asm/smp_plat.h>
#include <asm/cacheflush.h>
+#include <asm/cputype.h>
#include <asm/suspend.h>
#include <asm/mcpm.h>
#include <asm/bL_switcher.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/power_cpu_migrate.h>
+
/*
* Use our own MPIDR accessors as the generic ones in asm/cputype.h have
@@ -51,6 +56,16 @@ static int read_mpidr(void)
}
/*
+ * Get a global nanosecond time stamp for tracing.
+ */
+static s64 get_ns(void)
+{
+ struct timespec ts;
+ getnstimeofday(&ts);
+ return timespec_to_ns(&ts);
+}
+
+/*
* bL switcher core code.
*/
@@ -201,6 +216,7 @@ static int bL_switch_to(unsigned int new_cluster_id)
*/
local_irq_disable();
local_fiq_disable();
+ trace_cpu_migrate_begin(get_ns(), mpidr & MPIDR_HWID_BITMASK);
/* redirect GIC's SGIs to our counterpart */
gic_migrate_target(bL_gic_id[cpuid][ib_cluster]);
@@ -250,6 +266,7 @@ static int bL_switch_to(unsigned int new_cluster_id)
tdev->evtdev->next_event, 1);
}
+ trace_cpu_migrate_finish(get_ns(), mpidr & MPIDR_HWID_BITMASK);
local_fiq_enable();
local_irq_enable();
diff --git a/include/trace/events/power_cpu_migrate.h b/include/trace/events/power_cpu_migrate.h
new file mode 100644
index 00000000000..3694af0f5bc
--- /dev/null
+++ b/include/trace/events/power_cpu_migrate.h
@@ -0,0 +1,66 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM power
+
+#if !defined(_TRACE_POWER_CPU_MIGRATE_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_POWER_CPU_MIGRATE_H
+
+#include <linux/tracepoint.h>
+
+#define __cpu_migrate_proto \
+ TP_PROTO(u64 timestamp, \
+ u32 cpu_hwid)
+#define __cpu_migrate_args \
+ TP_ARGS(timestamp, \
+ cpu_hwid)
+
+DECLARE_EVENT_CLASS(cpu_migrate,
+
+ __cpu_migrate_proto,
+ __cpu_migrate_args,
+
+ TP_STRUCT__entry(
+ __field(u64, timestamp )
+ __field(u32, cpu_hwid )
+ ),
+
+ TP_fast_assign(
+ __entry->timestamp = timestamp;
+ __entry->cpu_hwid = cpu_hwid;
+ ),
+
+ TP_printk("timestamp=%llu cpu_hwid=0x%08lX",
+ (unsigned long long)__entry->timestamp,
+ (unsigned long)__entry->cpu_hwid
+ )
+);
+
+#define __define_cpu_migrate_event(name) \
+ DEFINE_EVENT(cpu_migrate, cpu_migrate_##name, \
+ __cpu_migrate_proto, \
+ __cpu_migrate_args \
+ )
+
+__define_cpu_migrate_event(begin);
+__define_cpu_migrate_event(finish);
+
+#undef __define_cpu_migrate
+#undef __cpu_migrate_proto
+#undef __cpu_migrate_args
+
+/* This file can get included multiple times, TRACE_HEADER_MULTI_READ at top */
+#ifndef _PWR_CPU_MIGRATE_EVENT_AVOID_DOUBLE_DEFINING
+#define _PWR_CPU_MIGRATE_EVENT_AVOID_DOUBLE_DEFINING
+
+/*
+ * Set from_phys_cpu and to_phys_cpu to CPU_MIGRATE_ALL_CPUS to indicate
+ * a whole-cluster migration:
+ */
+#define CPU_MIGRATE_ALL_CPUS 0x80000000U
+#endif
+
+#endif /* _TRACE_POWER_CPU_MIGRATE_H */
+
+/* This part must be outside protection */
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE power_cpu_migrate
+#include <trace/define_trace.h>