From 8179672c2f7b9c41a7ef3e8c907d214fa92ed614 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Wed, 13 Aug 2014 11:26:21 -0300 Subject: [PATCH] perf evlist: Monitor POLLERR and POLLHUP events too 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 Cc: Adrian Hunter Cc: David Ahern Cc: Don Zickus Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-a4fslwspov0bs69nj825hqpq@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- 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++; } -- 2.20.1