From e36b7821a985325dd7074de96deface5c9c6d700 Mon Sep 17 00:00:00 2001 From: Alexis Berlemont Date: Mon, 10 Oct 2016 07:43:28 +0200 Subject: [PATCH] perf trace: Implement --delay In the perf wiki todo-list[1], there is an entry regarding initial-delay and 'perf trace'; the following small patch tries to fulfill this point. It has been generated against the branch tip/perf/core. It has only been implemented in the "trace__run" case. Ex.: $ sudo strace -- ./perf trace --delay 5 sleep 1 2>&1 ... fcntl(7, F_SETFL, O_RDONLY|O_NONBLOCK) = 0 ioctl(7, PERF_EVENT_IOC_ID, 0x7ffc8fd35718) = 0 ioctl(11, PERF_EVENT_IOC_SET_OUTPUT, 0x7) = 0 fcntl(11, F_SETFL, O_RDONLY|O_NONBLOCK) = 0 ioctl(11, PERF_EVENT_IOC_ID, 0x7ffc8fd35718) = 0 write(6, "\0", 1) = 1 close(6) = 0 nanosleep({0, 5000000}, NULL) = 0 # DELAY OF 5 MS BEFORE ENABLING THE EVENTS ioctl(3, PERF_EVENT_IOC_ENABLE, 0) = 0 ioctl(4, PERF_EVENT_IOC_ENABLE, 0) = 0 ioctl(5, PERF_EVENT_IOC_ENABLE, 0) = 0 ioctl(7, PERF_EVENT_IOC_ENABLE, 0) = 0 ... [1]: https://perf.wiki.kernel.org/index.php/Todo Signed-off-by: Alexis Berlemont Suggested-and-Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20161010054328.4028-2-alexis.berlemont@gmail.com [ Add entry to the manpage, cut'n'pasted from stat's and record's ] Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/Documentation/perf-trace.txt | 5 +++++ tools/perf/builtin-trace.c | 10 +++++++++- 2 files changed, 14 insertions(+), 1 deletion(-) diff --git a/tools/perf/Documentation/perf-trace.txt b/tools/perf/Documentation/perf-trace.txt index 1ab0782..781b019 100644 --- a/tools/perf/Documentation/perf-trace.txt +++ b/tools/perf/Documentation/perf-trace.txt @@ -39,6 +39,11 @@ OPTIONS Prefixing with ! shows all syscalls but the ones specified. You may need to escape it. +-D msecs:: +--delay msecs:: +After starting the program, wait msecs before measuring. This is useful to +filter out the startup phase of the program, which is often very different. + -o:: --output=:: Output file name. diff --git a/tools/perf/builtin-trace.c b/tools/perf/builtin-trace.c index c298bd3..0bae454 100644 --- a/tools/perf/builtin-trace.c +++ b/tools/perf/builtin-trace.c @@ -2310,12 +2310,17 @@ static int trace__run(struct trace *trace, int argc, const char **argv) if (err < 0) goto out_error_mmap; - if (!target__none(&trace->opts.target)) + if (!target__none(&trace->opts.target) && !trace->opts.initial_delay) perf_evlist__enable(evlist); if (forks) perf_evlist__start_workload(evlist); + if (trace->opts.initial_delay) { + usleep(trace->opts.initial_delay * 1000); + perf_evlist__enable(evlist); + } + trace->multiple_threads = thread_map__pid(evlist->threads, 0) == -1 || evlist->threads->nr > 1 || perf_evlist__first(evlist)->attr.inherit; @@ -2816,6 +2821,9 @@ int cmd_trace(int argc, const char **argv, const char *prefix __maybe_unused) "Default: kernel.perf_event_max_stack or " __stringify(PERF_MAX_STACK_DEPTH)), OPT_UINTEGER(0, "proc-map-timeout", &trace.opts.proc_map_timeout, "per thread proc mmap processing timeout in ms"), + OPT_UINTEGER('D', "delay", &trace.opts.initial_delay, + "ms to wait before starting measurement after program " + "start"), OPT_END() }; bool __maybe_unused max_stack_user_set = true; -- 2.7.4