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Commit e36b7821 authored by Alexis Berlemont's avatar Alexis Berlemont Committed by Arnaldo Carvalho de Melo
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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: default avatarAlexis Berlemont <alexis.berlemont@gmail.com>
Suggested-and-Tested-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 21e8c810

tools/perf/Documentation/perf-trace.txt

+5 −0
Original line number Diff line number Diff line
@@ -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.

tools/perf/builtin-trace.c

+9 −1
Original line number Diff line number Diff line
@@ -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;