tracing: Add alternative synthetic event trace action syntax
Add a 'trace(synthetic_event_name, params)' alternative to
synthetic_event_name(params).
Currently, the syntax used for generating synthetic events is to
invoke synthetic_event_name(params) i.e. use the synthetic event name
as a function call.
Users requested a new form that more explicitly shows that the
synthetic event is in effect being traced. In this version, a new
'trace()' keyword is used, and the synthetic event name is passed in
as the first argument.
In addition, for the sake of consistency with other actions, change
the documention to emphasize the trace() form over the function-call
form, which remains documented as equivalent.
Link: http://lkml.kernel.org/r/d082773e50232a001480cf837679a1e01c1a2eb7.1550100284.git.tom.zanussi@linux.intel.com
Signed-off-by: Tom Zanussi <tom.zanussi@linux.intel.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index be6779f..0460cc0 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -4918,7 +4918,7 @@ static const char readme_msg[] =
"\t onmax(var) - invoke if var exceeds current max\n"
"\t onchange(var) - invoke action if var changes\n\n"
"\t The available actions are:\n\n"
- "\t <synthetic_event>(param list) - generate synthetic event\n"
+ "\t trace(<synthetic_event>,param list) - generate synthetic event\n"
"\t save(field,...) - save current event fields\n"
#ifdef CONFIG_TRACER_SNAPSHOT
"\t snapshot() - snapshot the trace buffer\n"
