Messages in this thread Patch in this message | | | From | Arnaldo Carvalho de Melo <> | Subject | [PATCH 03/14] perf evlist: Monitor POLLERR and POLLHUP events too | Date | Wed, 10 Sep 2014 11:08:38 -0300 |
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From: Arnaldo Carvalho de Melo <acme@redhat.com>
We want to know when the fd went away, like when a monitored thread exits.
If we do not monitor such events, then the tools will wait forever on events from a vanished thread, like when running:
$ sleep 5s & $ perf record -p `pidof sleep`
This builds upon the kernel patch by Jiri Olsa that actually makes a poll on those file descriptors to return POLLHUP.
It is also needed to change the tools to use perf_evlist__filter_pollfd() to check if there are remainings fds to monitor or if all are gone, in which case they will exit the poll/mmap/read loop.
Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-a4fslwspov0bs69nj825hqpq@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- tools/perf/util/evlist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c index 023bc3873ae9..502cd11ab17e 100644 --- a/tools/perf/util/evlist.c +++ b/tools/perf/util/evlist.c @@ -424,7 +424,7 @@ void perf_evlist__add_pollfd(struct perf_evlist *evlist, int fd) { fcntl(fd, F_SETFL, O_NONBLOCK); evlist->pollfd[evlist->nr_fds].fd = fd; - evlist->pollfd[evlist->nr_fds].events = POLLIN; + evlist->pollfd[evlist->nr_fds].events = POLLIN | POLLERR | POLLHUP; evlist->nr_fds++; } -- 1.9.3
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