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Message-Id: <20200711124035.6513-17-changbin.du@gmail.com>
Date: Sat, 11 Jul 2020 20:40:34 +0800
From: Changbin Du <changbin.du@...il.com>
To: Jiri Olsa <jolsa@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Namhyung Kim <namhyung@...nel.org>,
Steven Rostedt <rostedt@...dmis.org>,
linux-kernel@...r.kernel.org, Changbin Du <changbin.du@...il.com>
Subject: [PATCH v5 16/17] 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@...il.com>
---
tools/perf/Documentation/perf-ftrace.txt | 4 ++++
tools/perf/builtin-ftrace.c | 19 ++++++++++++++++---
2 files changed, 20 insertions(+), 3 deletions(-)
diff --git a/tools/perf/Documentation/perf-ftrace.txt b/tools/perf/Documentation/perf-ftrace.txt
index 97d89478ff5f..62f56058de54 100644
--- a/tools/perf/Documentation/perf-ftrace.txt
+++ b/tools/perf/Documentation/perf-ftrace.txt
@@ -42,6 +42,10 @@ OPTIONS
--tid=::
Trace on existing thread 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 86fc5d466e97..a70951938308 100644
--- a/tools/perf/builtin-ftrace.c
+++ b/tools/perf/builtin-ftrace.c
@@ -47,6 +47,7 @@ struct perf_ftrace {
int graph_noirqs;
int graph_verbose;
int graph_thresh;
+ unsigned int initial_delay;
};
struct filter_entry {
@@ -591,13 +592,23 @@ 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;
@@ -808,6 +819,8 @@ 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()
};
--
2.25.1
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