perf probe: Generate event name with line number

Generate event name from function name with line number as
<function>_L<line_number>. Note that this is only for the new event
which is defined by the line number of function (except for line 0).

If there is another event on same line, you have to use
"-f" option. In that case, the new event has "_1" suffix.

 e.g.
  # perf probe -a kernel_read:2
  Added new event:
    probe:kernel_read_L2 (on kernel_read:2)

  You can now use it in all perf tools, such as:

  	perf record -e probe:kernel_read_L2 -aR sleep 1

But if we omit the line number or 0th line, it will
have no suffix.

  # perf probe -a kernel_read:0
  Added new event:
    probe:kernel_read (on kernel_read)

  You can now use it in all perf tools, such as:

  	perf record -e probe:kernel_read -aR sleep 1

  probe:kernel_read    (on [email protected]/fs/read_write.c)
  probe:kernel_read_L2 (on kernel_read:[email protected]/fs/read_write.c)

Signed-off-by: Masami Hiramatsu <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Ravi Bangoria <[email protected]>
Cc: Steven Rostedt (VMware) <[email protected]>
Cc: Tom Zanussi <[email protected]>
Link: http://lore.kernel.org/lkml/157406474026.24476.2828897745502059569.stgit@devnote2
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

1 files changed, 8 insertions, 0 deletions

diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index e29948b8fcab..5c86d2cf6338 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1679,6 +1679,14 @@ int parse_perf_probe_command(const char *cmd, struct perf_probe_event *pev)
 	if (ret < 0)
 		goto out;
 
+	/* Generate event name if needed */
+	if (!pev->event && pev->point.function && pev->point.line
+			&& !pev->point.lazy_line && !pev->point.offset) {
+		if (asprintf(&pev->event, "%s_L%d", pev->point.function,
+			pev->point.line) < 0)
+			return -ENOMEM;
+	}
+
 	/* Copy arguments and ensure return probe has no C argument */
 	pev->nargs = argc - 1;
 	pev->args = zalloc(sizeof(struct perf_probe_arg) * pev->nargs);