This adds an option '-d/--delay' to allow us to start tracing some times later after workload is launched.
Signed-off-by: Changbin Du <[email protected]> --- 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 e204bf6d50d8..fd1776deebd7 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 b427ab3977ad..dceae70c3a22 100644 --- a/tools/perf/builtin-ftrace.c +++ b/tools/perf/builtin-ftrace.c @@ -38,6 +38,7 @@ struct perf_ftrace { struct list_head graph_funcs; struct list_head nograph_funcs; int graph_depth; + unsigned initial_delay; }; struct filter_entry { @@ -402,13 +403,23 @@ static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv) fcntl(trace_fd, F_SETFL, O_NONBLOCK); pollfd.fd = trace_fd; - 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; @@ -535,6 +546,8 @@ int cmd_ftrace(int argc, const char **argv) "Set nograph filter on given functions", parse_filter_func), OPT_INTEGER('D', "graph-depth", &ftrace.graph_depth, "Max depth for function graph tracer"), + OPT_UINTEGER('d', "delay", &ftrace.initial_delay, + "ms to wait before starting tracing after program start"), OPT_END() }; -- 2.25.1
