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authorSteven Rostedt (Red Hat) <rostedt@goodmis.org>2013-03-14 17:13:45 (GMT)
committerSteven Rostedt <rostedt@goodmis.org>2013-03-15 04:36:09 (GMT)
commit8aacf017b065a805d27467843490c976835eb4a5 (patch)
tree3e3ee23502cf2cc6d02baa1f7625b1ef16611eda /kernel
parent328df4759c03e2c3e7429cc6cb0e180c38f32063 (diff)
downloadlinux-fsl-qoriq-8aacf017b065a805d27467843490c976835eb4a5.tar.xz
tracing: Add "uptime" trace clock that uses jiffies
Add a simple trace clock called "uptime" for those that are interested in the uptime of the trace. It uses jiffies as that's the safest method, as other uptime clocks grab seq locks, which could cause a deadlock if taken from an event or function tracer. Requested-by: Mauro Carvalho Chehab <mchehab@redhat.com> Cc: Thomas Gleixner <tglx@linutronix.de Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Frederic Weisbecker <fweisbec@gmail.com> Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/trace/trace.c1
-rw-r--r--kernel/trace/trace_clock.c10
2 files changed, 11 insertions, 0 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index f90ca16..8eabfbb 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -647,6 +647,7 @@ static struct {
{ trace_clock_local, "local", 1 },
{ trace_clock_global, "global", 1 },
{ trace_clock_counter, "counter", 0 },
+ { trace_clock_jiffies, "uptime", 1 },
ARCH_TRACE_CLOCKS
};
diff --git a/kernel/trace/trace_clock.c b/kernel/trace/trace_clock.c
index aa8f5f4..26dc348 100644
--- a/kernel/trace/trace_clock.c
+++ b/kernel/trace/trace_clock.c
@@ -57,6 +57,16 @@ u64 notrace trace_clock(void)
return local_clock();
}
+/*
+ * trace_jiffy_clock(): Simply use jiffies as a clock counter.
+ */
+u64 notrace trace_clock_jiffies(void)
+{
+ u64 jiffy = jiffies - INITIAL_JIFFIES;
+
+ /* Return nsecs */
+ return (u64)jiffies_to_usecs(jiffy) * 1000ULL;
+}
/*
* trace_clock_global(): special globally coherent trace clock