Commit f3058a1c authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
Browse files

perf evlist: Don't poll and mmap overwritable events 



There's no need to receive events from overwritable ring buffer.
Instead, perf should make them run in background until some external
event of interest takes place.  This patch makes ignores normal events from
overwrite evlists.

Overwritable events must be mapped readonly and backward, so if evlist
and evsel doesn't match (evsel->overwrite is true but either evlist is
read/write or evlist is not backward, and vice versa), skip mapping it.

Signed-off-by: default avatarWang Nan <wangnan0@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1464056944-166978-3-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarHe Kuang <hekuang@huawei.com>
[ Split from a larger patch ]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent c45628b0

tools/perf/util/evlist.c

+19 −4
Original line number Diff line number Diff line
@@ -462,9 +462,9 @@ int perf_evlist__alloc_pollfd(struct perf_evlist *evlist) 
	return 0;

}



static int __perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd, int idx)

static int __perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd, int idx, short revent)

{

	int pos = fdarray__add(&evlist->pollfd, fd, POLLIN | POLLERR | POLLHUP);

	int pos = fdarray__add(&evlist->pollfd, fd, revent | POLLERR | POLLHUP);

	/*

	 * Save the idx so that when we filter out fds POLLHUP'ed we can

	 * close the associated evlist->mmap[] entry.
@@ -480,7 +480,7 @@ static int __perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd, int idx 


int perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd)

{

	return __perf_evlist__add_pollfd(evlist, fd, -1);

	return __perf_evlist__add_pollfd(evlist, fd, -1, POLLIN);

}



static void perf_evlist__munmap_filtered(struct fdarray *fda, int fd)
@@ -983,15 +983,28 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx, 
	return 0;

}



static bool

perf_evlist__should_poll(struct perf_evlist *evlist __maybe_unused,

			 struct perf_evsel *evsel)

{

	if (evsel->overwrite)

		return false;

	return true;

}



static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,

				       struct mmap_params *mp, int cpu,

				       int thread, int *output)

{

	struct perf_evsel *evsel;

	int revent;



	evlist__for_each(evlist, evsel) {

		int fd;



		if (evsel->overwrite != (evlist->overwrite && evlist->backward))

			continue;



		if (evsel->system_wide && thread)

			continue;
@@ -1008,6 +1021,8 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx, 
			perf_evlist__mmap_get(evlist, idx);

		}



		revent = perf_evlist__should_poll(evlist, evsel) ? POLLIN : 0;



		/*

		 * The system_wide flag causes a selected event to be opened

		 * always without a pid.  Consequently it will never get a
@@ -1016,7 +1031,7 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx, 
		 * Therefore don't add it for polling.

		 */

		if (!evsel->system_wide &&

		    __perf_evlist__add_pollfd(evlist, fd, idx) < 0) {

		    __perf_evlist__add_pollfd(evlist, fd, idx, revent) < 0) {

			perf_evlist__mmap_put(evlist, idx);

			return -1;

		}

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