Hi -
> [...] How about creating trace_tick() in
> include/trace/events/timer.h and call it from tick_periodic() and
> tick_sched_handle(). [...]
Like this?
>From facee64445c0dcc717e99c474c5c7dcdd31b9a74 Mon Sep 17 00:00:00 2001
From: "Frank Ch. Eigler" <f...@redhat.com>
Date: Wed, 3 Apr 2013 10:35:21 -0400
Subject: [PATCH] profiling: add tick tracepoint
Commit ba6fdda4 removed the timer_hook mechanism for modules to listen
to profiling timer ticks (without having to set up more complicated
perf mechanisms). To reduce the impact on out-of-tree users such as
systemtap, a TRACE_EVENT-flavoured tracepoint is added in its place,
invoked right beside profile_tick() in kernel/time/tick-*.c.
Tested with perf and systemtap.
Cc: Frederic Weisbecker <fweis...@gmail.com>
Cc: Ingo Molnar <mi...@kernel.org>
Cc: Mel Gorman <mgor...@suse.de>
Signed-off-by: Frank Ch. Eigler <f...@redhat.com>
---
include/trace/events/timer.h | 20 ++++++++++++++++++++
kernel/time/tick-common.c | 2 ++
kernel/time/tick-sched.c | 2 ++
3 files changed, 24 insertions(+)
diff --git a/include/trace/events/timer.h b/include/trace/events/timer.h
index 425bcfe..ec4c2d0 100644
--- a/include/trace/events/timer.h
+++ b/include/trace/events/timer.h
@@ -323,6 +323,26 @@ TRACE_EVENT(itimer_expire,
(int) __entry->pid, (unsigned long long)__entry->now)
);
+
+struct pt_regs;
+
+/**
+ * tick - called when the profiling timer ticks
+ * @regs: pointer to struct pt_regs*
+ */
+TRACE_EVENT(tick,
+ TP_PROTO(struct pt_regs *regs),
+ TP_ARGS(regs),
+ TP_STRUCT__entry(
+ __field( struct pt_regs*, regs )
+ ),
+ TP_fast_assign(
+ __entry->regs = regs;
+ ),
+ TP_printk("ip=%p", (void *) instruction_pointer(__entry->regs))
+);
+
+
#endif /* _TRACE_TIMER_H */
/* This part must be outside protection */
diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c
index b1600a6..5f4227f 100644
--- a/kernel/time/tick-common.c
+++ b/kernel/time/tick-common.c
@@ -18,6 +18,7 @@
#include <linux/percpu.h>
#include <linux/profile.h>
#include <linux/sched.h>
+#include <trace/events/timer.h>
#include <asm/irq_regs.h>
@@ -74,6 +75,7 @@ static void tick_periodic(int cpu)
update_process_times(user_mode(get_irq_regs()));
profile_tick(CPU_PROFILING);
+ trace_tick(get_irq_regs());
}
/*
diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
index a19a399..447be56 100644
--- a/kernel/time/tick-sched.c
+++ b/kernel/time/tick-sched.c
@@ -21,6 +21,7 @@
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/irq_work.h>
+#include <trace/events/timer.h>
#include <asm/irq_regs.h>
@@ -140,6 +141,7 @@ static void tick_sched_handle(struct tick_sched *ts, struct
pt_regs *regs)
#endif
update_process_times(user_mode(regs));
profile_tick(CPU_PROFILING);
+ trace_tick(get_irq_regs());
}
/*
--
1.8.2
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