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Commit 65aea233 authored by Wang Nan's avatar Wang Nan Committed by Arnaldo Carvalho de Melo
Browse files

perf evlist: Add API to pause/resume 



perf_evlist__toggle_{pause,resume}() are introduced to pause/resume
events in an evlist. Utilize PERF_EVENT_IOC_PAUSE_OUTPUT ioctl.

Following commits use them to ensure overwrite ring buffer is paused
before reading.

Signed-off-by: default avatarWang Nan <wangnan0@huawei.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Zefan Li <lizefan@huawei.com>
Cc: pi3orama@163.com
Link: http://lkml.kernel.org/r/1463987628-163563-2-git-send-email-wangnan0@huawei.com


Signed-off-by: default avatarHe Kuang <hekuang@huawei.com>
[ Return -1, like all other ioctl() usage in evlist.c, rename 'pause'
  arg to avoid breaking the build on ubuntu 12.04 and other old systems ]
Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 12f3ca4f

tools/perf/util/evlist.c

+27 −0
Original line number Diff line number Diff line
@@ -679,6 +679,33 @@ static struct perf_evsel *perf_evlist__event2evsel(struct perf_evlist *evlist, 
	return NULL;

}



static int perf_evlist__set_paused(struct perf_evlist *evlist, bool value)

{

	int i;



	for (i = 0; i < evlist->nr_mmaps; i++) {

		int fd = evlist->mmap[i].fd;

		int err;



		if (fd < 0)

			continue;

		err = ioctl(fd, PERF_EVENT_IOC_PAUSE_OUTPUT, value ? 1 : 0);

		if (err)

			return err;

	}

	return 0;

}



int perf_evlist__pause(struct perf_evlist *evlist)

{

	return perf_evlist__set_paused(evlist, true);

}



int perf_evlist__resume(struct perf_evlist *evlist)

{

	return perf_evlist__set_paused(evlist, false);

}



/* When check_messup is true, 'end' must points to a good entry */

static union perf_event *

perf_mmap__read(struct perf_mmap *md, bool check_messup, u64 start,

tools/perf/util/evlist.h

+2 −0
Original line number Diff line number Diff line
@@ -136,6 +136,8 @@ void perf_evlist__mmap_read_catchup(struct perf_evlist *evlist, int idx); 


void perf_evlist__mmap_consume(struct perf_evlist *evlist, int idx);



int perf_evlist__pause(struct perf_evlist *evlist);

int perf_evlist__resume(struct perf_evlist *evlist);

int perf_evlist__open(struct perf_evlist *evlist);

void perf_evlist__close(struct perf_evlist *evlist);