Em Fri, May 13, 2016 at 07:56:05AM +0000, Wang Nan escreveu:
> There's no need to receive events from overwritable ring buffer. Instead,
> perf should make them run background until something happen. This patch
> makes normal events from overwrite ring buffer ignored.
>
> Signed-off-by: Wang Nan <[email protected]>
> Signed-off-by: He Kuang <[email protected]>
> Cc: Arnaldo Carvalho de Melo <[email protected]>
> Cc: Jiri Olsa <[email protected]>
> Cc: Masami Hiramatsu <[email protected]>
> Cc: Namhyung Kim <[email protected]>
> Cc: Zefan Li <[email protected]>
> Cc: [email protected]
> ---
> tools/perf/util/evlist.c | 23 +++++++++++++++++++----
> 1 file changed, 19 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
> index abce588..f0b0457 100644
> --- a/tools/perf/util/evlist.c
> +++ b/tools/perf/util/evlist.c
> @@ -461,9 +461,9 @@ 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.
> @@ -479,7 +479,7 @@ 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)
> @@ -1077,6 +1077,18 @@ perf_evlist__channel_complete(struct perf_evlist
> *evlist)
> return 0;
> }
>
> +static bool
> +perf_evlist__should_poll(struct perf_evlist *evlist,
> + struct perf_evsel *evsel,
> + int channel)
> +{
> + if (evsel->system_wide)
> + return false;
So, what is the above doing in this patch? If we should not poll when in
syswide mode, then this should be in a separate patch, unrelated to
'channels'. No?
I.e. it would be an improvement that would be cherry pickable right now,
even before reviewing the channel concept.
- Arnaldo
> + if (perf_evlist__channel_check(evlist, channel, RDONLY))
> + 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 *outputs)
> @@ -1085,6 +1097,7 @@ static int perf_evlist__mmap_per_evsel(struct
> perf_evlist *evlist, int _idx,
>
> evlist__for_each(evlist, evsel) {
> int fd, channel, idx, err;
> + short revent = POLLIN;
>
> channel = perf_evlist__channel_find(evlist, evsel, false);
> if (channel < 0) {
> @@ -1114,6 +1127,8 @@ static int perf_evlist__mmap_per_evsel(struct
> perf_evlist *evlist, int _idx,
> perf_evlist__mmap_get(evlist, idx);
> }
>
> + if (!perf_evlist__should_poll(evlist, evsel, channel))
> + revent = 0;
> /*
> * The system_wide flag causes a selected event to be opened
> * always without a pid. Consequently it will never get a
> @@ -1122,7 +1137,7 @@ 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;
> }
> --
> 1.8.3.4
