[PATCH v8 16/18] perf ftrace: add option --tid to filter by thread id

[Changbin Du]

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

Signed-off-by: Changbin Du <changbin.du@xxxxxxxxx>
---
 tools/perf/Documentation/perf-ftrace.txt | 3 +++
 tools/perf/builtin-ftrace.c              | 3 +++
 2 files changed, 6 insertions(+)

diff --git a/tools/perf/Documentation/perf-ftrace.txt b/tools/perf/Documentation/perf-ftrace.txt
index 29c684b3b3fd..78358af9a1c4 100644
--- a/tools/perf/Documentation/perf-ftrace.txt
+++ b/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.
diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index 5f9a9ebea0a2..13abb737fd12 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/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,
-- 
2.25.1