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authorChris Redpath <chris.redpath@arm.com>2013-10-11 11:45:01 +0100
committerJon Medhurst <tixy@linaro.org>2013-10-11 15:07:18 +0100
commit5ecaba3d9f4ab514fe8d383534e24b306f116896 (patch)
tree9b35196c582b427400e8a910cd5c3686979e7cd3
parent2353c1f8009c14e89b323b18ae246c485fc034e4 (diff)
downloadlinaro-lsk-5ecaba3d9f4ab514fe8d383534e24b306f116896.tar.gz
smp: smp_cross_call function pointer tracing
generic tracing for smp_cross_call function calls Signed-off-by: Chris Redpath <chris.redpath@arm.com> Signed-off-by: Liviu Dudau <Liviu.Dudau@arm.com> Signed-off-by: Jon Medhurst <tixy@linaro.org>
-rw-r--r--include/trace/events/smp.h91
-rw-r--r--kernel/smp.c12
2 files changed, 101 insertions, 2 deletions
diff --git a/include/trace/events/smp.h b/include/trace/events/smp.h
new file mode 100644
index 00000000000..c8abfd74472
--- /dev/null
+++ b/include/trace/events/smp.h
@@ -0,0 +1,91 @@
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM smp
+
+#if !defined(_TRACE_SMP_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_SMP_H
+
+#include <linux/tracepoint.h>
+typedef void (*__smp_call_func_t)(void *info);
+
+DECLARE_EVENT_CLASS(smp_call_class,
+
+ TP_PROTO(__smp_call_func_t fnc),
+
+ TP_ARGS(fnc),
+
+ TP_STRUCT__entry(
+ __field( void *, func )
+ ),
+
+ TP_fast_assign(
+ __entry->func = fnc;
+ ),
+
+ TP_printk("func=%pf", __entry->func)
+);
+
+/**
+ * smp_call_func_entry - called in the generic smp-cross-call-handler
+ * immediately before calling the destination
+ * function
+ * @func: function pointer
+ *
+ * When used in combination with the smp_call_func_exit tracepoint
+ * we can determine the cross-call runtime.
+ */
+DEFINE_EVENT(smp_call_class, smp_call_func_entry,
+
+ TP_PROTO(__smp_call_func_t fnc),
+
+ TP_ARGS(fnc)
+);
+
+/**
+ * smp_call_func_exit - called in the generic smp-cross-call-handler
+ * immediately after the destination function
+ * returns
+ * @func: function pointer
+ *
+ * When used in combination with the smp_call_entry tracepoint
+ * we can determine the cross-call runtime.
+ */
+DEFINE_EVENT(smp_call_class, smp_call_func_exit,
+
+ TP_PROTO(__smp_call_func_t fnc),
+
+ TP_ARGS(fnc)
+);
+
+/**
+ * smp_call_func_send - called as destination function is set
+ * in the per-cpu storage
+ * @func: function pointer
+ * @dest: cpu to send to
+ *
+ * When used in combination with the smp_cross_call_entry tracepoint
+ * we can determine the call-to-run latency.
+ */
+TRACE_EVENT(smp_call_func_send,
+
+ TP_PROTO(__smp_call_func_t func, int dest),
+
+ TP_ARGS(func, dest),
+
+ TP_STRUCT__entry(
+ __field( void * , func )
+ __field( int , dest )
+ ),
+
+ TP_fast_assign(
+ __entry->func = func;
+ __entry->dest = dest;
+ ),
+
+ TP_printk("dest=%d func=%pf", __entry->dest,
+ __entry->func)
+);
+
+#endif /* _TRACE_SMP_H */
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>
diff --git a/kernel/smp.c b/kernel/smp.c
index 4dba0f7b72a..23ccc67dcbb 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -12,6 +12,8 @@
#include <linux/gfp.h>
#include <linux/smp.h>
#include <linux/cpu.h>
+#define CREATE_TRACE_POINTS
+#include <trace/events/smp.h>
#include "smpboot.h"
@@ -159,8 +161,10 @@ void generic_exec_single(int cpu, struct call_single_data *csd, int wait)
* locking and barrier primitives. Generic code isn't really
* equipped to do the right thing...
*/
- if (ipi)
+ if (ipi) {
+ trace_smp_call_func_send(csd->func, cpu);
arch_send_call_function_single_ipi(cpu);
+ }
if (wait)
csd_lock_wait(csd);
@@ -197,8 +201,9 @@ void generic_smp_call_function_single_interrupt(void)
* so save them away before making the call:
*/
csd_flags = csd->flags;
-
+ trace_smp_call_func_entry(csd->func);
csd->func(csd->info);
+ trace_smp_call_func_exit(csd->func);
/*
* Unlocked CSDs are valid through generic_exec_single():
@@ -228,6 +233,7 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
int this_cpu;
int err = 0;
+ trace_smp_call_func_send(func, cpu);
/*
* prevent preemption and reschedule on another processor,
* as well as CPU removal
@@ -245,7 +251,9 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
if (cpu == this_cpu) {
local_irq_save(flags);
+ trace_smp_call_func_entry(func);
func(info);
+ trace_smp_call_func_exit(func);
local_irq_restore(flags);
} else {
if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) {