Commit d8279bfc authored Mar 16, 2021 by Steven Rostedt (VMware)

tracing: Add tracing_event_time_stamp() API

Add a tracing_event_time_stamp() API that checks if the event passed in is
not on the ring buffer but a pointer to the per CPU trace_buffered_event
which does not have its time stamp set yet.

If it is a pointer to the trace_buffered_event, then just return the
current time stamp that the ring buffer would produce.

Otherwise, return the time stamp from the event.

Link: https://lkml.kernel.org/r/20210316164114.131996180@goodmis.org



Reviewed-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parent a948c69d

kernel/trace/trace.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -6972,6 +6972,14 @@ static int tracing_time_stamp_mode_open(struct inode inode, struct file file)
		return ret;
		}

		u64 tracing_event_time_stamp(struct trace_buffer buffer, struct ring_buffer_event rbe)
		{
		if (rbe == this_cpu_read(trace_buffered_event))
		return ring_buffer_time_stamp(buffer, smp_processor_id());

		return ring_buffer_event_time_stamp(buffer, rbe);
		}

		/*
		* Set or disable using the per CPU trace_buffer_event when possible.
		*/

kernel/trace/trace.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -372,6 +372,7 @@ extern int tracing_check_open_get_tr(struct trace_array *tr);
		extern struct trace_array trace_array_find(const char instance);
		extern struct trace_array trace_array_find_get(const char instance);

		extern u64 tracing_event_time_stamp(struct trace_buffer buffer, struct ring_buffer_event rbe);
		extern int tracing_set_filter_buffering(struct trace_array *tr, bool set);
		extern int tracing_set_clock(struct trace_array tr, const char clockstr);