Messages in this thread Patch in this message |  | | From | Wang Nan <> | Subject | [PATCH 50/55] perf tools: Add API to pause a channel | Date | Fri, 19 Feb 2016 11:44:38 +0000 |
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perf_evlist__channel_toggle_paused() is introduced to pause/resume a channel in an evlist. Utilize PERF_EVENT_IOC_PAUSE_OUTPUT ioctl. Following commits use perf_evlist__channel_toggle_paused() to ensure overwrite ring buffer is turned off before reading.
Signed-off-by: Wang Nan <wangnan0@huawei.com> Signed-off-by: He Kuang <hekuang@huawei.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.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 --- tools/perf/util/evlist.c | 28 ++++++++++++++++++++++++++++ tools/perf/util/evlist.h | 2 ++ 2 files changed, 30 insertions(+)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index bd2393a..06c79c8 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -706,6 +706,34 @@ int perf_evlist__channel_idx(struct perf_evlist *evlist, return 0; } +int perf_evlist__channel_toggle_paused(struct perf_evlist *evlist, + int channel, bool pause) +{ + int i; + + if (channel >= perf_evlist__channel_nr(evlist)) + return -E2BIG; + if (!evlist->mmap) + return -EFAULT; + for (i = 0; i < evlist->nr_mmaps; i++) { + int n = channel * evlist->nr_mmaps + i; + int fd = evlist->mmap[n].fd; + int err; + + if (fd < 0) + continue; + err = ioctl(fd, PERF_EVENT_IOC_PAUSE_OUTPUT, + pause ? 1 : 0); + if (err) { + err = (errno == 0 ? -EINVAL : -errno); + pr_err("Unable to pause output on %d: %s\n", + fd, strerror(-err)); + return err; + } + } + return 0; +} + union perf_event *perf_evlist__mmap_read_ex(struct perf_evlist *evlist, int channel, int idx) { diff --git a/tools/perf/util/evlist.h b/tools/perf/util/evlist.h index bc6d787..c1831a9 100644 --- a/tools/perf/util/evlist.h +++ b/tools/perf/util/evlist.h @@ -180,6 +180,8 @@ perf_evlist__get_mmap(struct perf_evlist *evlist, return &evlist->mmap[idx]; } +int perf_evlist__channel_toggle_paused(struct perf_evlist *evlist, + int channel, bool pause); int perf_evlist__open(struct perf_evlist *evlist); void perf_evlist__close(struct perf_evlist *evlist); -- 1.8.3.4
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