On Wed, May 20, 2020 at 06:13:31PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Sun, May 10, 2020 at 11:06:26PM +0800, Changbin Du escreveu:
> > This adds an option '-d/--delay' to allow us to start tracing some
> > times later after workload is launched.
>
> [acme@five perf]$ perf record -h delay
>
> Usage: perf record [<options>] [<command>]
> or: perf record [<options>] -- <command> [<options>]
>
> -D, --delay <n> ms to wait before starting measurement after
> program start
>
> [acme@five perf]$
>
Sure, will change the short option name.
> > Signed-off-by: Changbin Du <changbin...@gmail.com>
> > ---
> > tools/perf/builtin-ftrace.c | 19 ++++++++++++++++---
> > 1 file changed, 16 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/perf/builtin-ftrace.c b/tools/perf/builtin-ftrace.c
> > index 8d04e5afe2d3..d376b37c53fc 100644
> > --- a/tools/perf/builtin-ftrace.c
> > +++ b/tools/perf/builtin-ftrace.c
> > @@ -49,6 +49,7 @@ struct perf_ftrace {
> > bool trace_children;
> > unsigned buffer_size_kb;
> > bool no_pager;
> > + unsigned initial_delay;
> > };
> >
> > struct filter_entry {
> > @@ -617,13 +618,23 @@ 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;
> > @@ -747,6 +758,8 @@ int cmd_ftrace(int argc, const char **argv)
> > "size of per cpu buffer in kb"),
> > OPT_BOOLEAN('P', "no-pager", &ftrace.no_pager,
> > "Do not use pager"),
> > + OPT_UINTEGER('d', "delay", &ftrace.initial_delay,
> > + "Wait <n> ms before tracing"),
> > OPT_END()
> > };
> >
> > --
> > 2.25.1
> >
>
> --
>
> - Arnaldo
--
Cheers,
Changbin Du
