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authorChangbin Du <changbin.du@gmail.com>2020-08-08 10:31:38 +0800
committerArnaldo Carvalho de Melo <acme@redhat.com>2020-08-14 09:34:05 -0300
commit6555c2f6db2196ef1b6d7149e7d342d0ba2ec57e (patch)
tree8947f6bf842991b0c7af88b5cf4e77c087a939b4 /tools
parenta8f87a5cb466888bb70330b9ba55cdc0b9a1c20e (diff)
downloadlinux-6555c2f6db2196ef1b6d7149e7d342d0ba2ec57e.tar.bz2
perf ftrace: Add option -D/--delay to delay tracing
This adds an option '-D/--delay' to allow us to start tracing some times later after workload is launched. Signed-off-by: Changbin Du <changbin.du@gmail.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Link: http://lore.kernel.org/lkml/20200808023141.14227-16-changbin.du@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools')
-rw-r--r--tools/perf/Documentation/perf-ftrace.txt4
-rw-r--r--tools/perf/builtin-ftrace.c19
2 files changed, 20 insertions, 3 deletions
diff --git a/tools/perf/Documentation/perf-ftrace.txt b/tools/perf/Documentation/perf-ftrace.txt
index 08216634d2bc..29c684b3b3fd 100644
--- a/tools/perf/Documentation/perf-ftrace.txt
+++ b/tools/perf/Documentation/perf-ftrace.txt
@@ -39,6 +39,10 @@ OPTIONS
--pid=::
Trace on existing process id (comma separated list).
+-D::
+--delay::
+ Time (ms) to wait before starting tracing after program start.
+
-a::
--all-cpus::
Force system-wide collection. Scripts run without a <command>
diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
index bc3b35d18167..5f9a9ebea0a2 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -49,6 +49,7 @@ struct perf_ftrace {
int graph_noirqs;
int graph_verbose;
int graph_thresh;
+ unsigned int initial_delay;
};
struct filter_entry {
@@ -596,13 +597,23 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
/* display column headers */
read_tracing_file_to_stdout("trace");
- if (write_tracing_file("tracing_on", "1") < 0) {
- pr_err("can't enable tracing\n");
- goto out_close_fd;
+ if (!ftrace->initial_delay) {
+ if (write_tracing_file("tracing_on", "1") < 0) {
+ pr_err("can't enable tracing\n");
+ goto out_close_fd;
+ }
}
perf_evlist__start_workload(ftrace->evlist);
+ if (ftrace->initial_delay) {
+ usleep(ftrace->initial_delay * 1000);
+ if (write_tracing_file("tracing_on", "1") < 0) {
+ pr_err("can't enable tracing\n");
+ goto out_close_fd;
+ }
+ }
+
while (!done) {
if (poll(&pollfd, 1, -1) < 0)
break;
@@ -827,6 +838,8 @@ int cmd_ftrace(int argc, const char **argv)
"size of per cpu buffer", parse_buffer_size),
OPT_BOOLEAN(0, "inherit", &ftrace.inherit,
"trace children processes"),
+ OPT_UINTEGER('D', "delay", &ftrace.initial_delay,
+ "ms to wait before starting tracing after program start"),
OPT_END()
};