perf ftrace: Add option --tid to filter by thread id

This allows us to trace single thread instead of the whole process.

Signed-off-by: Changbin Du <[email protected]>
Acked-by: Namhyung Kim <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Steven Rostedt (VMware) <[email protected]>
Link: http://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: changbindu

tools/perf/Documentation/perf-ftrace.txt

@@ -39,6 +39,9 @@ OPTIONS
 --pid=::
 	Trace on existing process id (comma separated list).
 
+--tid=::
+	Trace on existing thread id (comma separated list).
+
 -D::
 --delay::
 	Time (ms) to wait before starting tracing after program start.

tools/perf/builtin-ftrace.c

@@ -812,6 +812,9 @@ int cmd_ftrace(int argc, const char **argv)
 		    "Show available functions to filter"),
 	OPT_STRING('p', "pid", &ftrace.target.pid, "pid",
 		   "trace on existing process id"),
+	/* TODO: Add short option -t after -t/--tracer can be removed. */
+	OPT_STRING(0, "tid", &ftrace.target.tid, "tid",
+		   "trace on existing thread id (exclusive to --pid)"),
 	OPT_INCR('v', "verbose", &verbose,
 		 "be more verbose"),
 	OPT_BOOLEAN('a', "all-cpus", &ftrace.target.system_wide,