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: Wang 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: He 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: Arnaldo Carvalho de Melo <acme@redhat.com>
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@ -679,6 +679,33 @@ static struct perf_evsel *perf_evlist__event2evsel(struct perf_evlist *evlist,
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return NULL;
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}
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static int perf_evlist__set_paused(struct perf_evlist *evlist, bool value)
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{
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int i;
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for (i = 0; i < evlist->nr_mmaps; i++) {
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int fd = evlist->mmap[i].fd;
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int err;
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if (fd < 0)
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continue;
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err = ioctl(fd, PERF_EVENT_IOC_PAUSE_OUTPUT, value ? 1 : 0);
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if (err)
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return err;
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}
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return 0;
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}
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int perf_evlist__pause(struct perf_evlist *evlist)
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{
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return perf_evlist__set_paused(evlist, true);
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}
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int perf_evlist__resume(struct perf_evlist *evlist)
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{
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return perf_evlist__set_paused(evlist, false);
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}
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/* When check_messup is true, 'end' must points to a good entry */
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static union perf_event *
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perf_mmap__read(struct perf_mmap *md, bool check_messup, u64 start,
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@ -136,6 +136,8 @@ void perf_evlist__mmap_read_catchup(struct perf_evlist *evlist, int idx);
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void perf_evlist__mmap_consume(struct perf_evlist *evlist, int idx);
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int perf_evlist__pause(struct perf_evlist *evlist);
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int perf_evlist__resume(struct perf_evlist *evlist);
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int perf_evlist__open(struct perf_evlist *evlist);
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void perf_evlist__close(struct perf_evlist *evlist);
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