[PATCH 04/14] perf evlist: We need to poll all event file descriptors

From: Arnaldo Carvalho de Melo
Date: Thu Sep 25 2014 - 17:58:31 EST

From: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>

Because we want to notice when they get POLLHUP'ed, so that we can
figure out when all threads exited in a workload being monitored.

We can't just monitor the fds that were mmaped, we need to notice when
all the fds that were PERF_EVENT_IOC_SET_OUTPUT'ed too, because the mmap
stays even after the fd that originally was used to do the mmap call
went away, its only when all the set-output fds for a mmap are gone that
the mmap is.

Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Don Zickus <dzickus@xxxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Mike Galbraith <efault@xxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Paul Mackerras <paulus@xxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Stephane Eranian <eranian@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/20140908151016.GH17728@xxxxxxxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/n/tip-24omlq5asrfg4uo3muuzn2bl@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
tools/perf/util/evlist.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 502cd11ab17e..6b13bfa7ac2c 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -717,8 +717,6 @@ static int __perf_evlist__mmap(struct perf_evlist *evlist, int idx,
evlist->mmap[idx].base = NULL;
return -1;
- perf_evlist__add_pollfd(evlist, fd);
return 0;

@@ -745,6 +743,8 @@ static int perf_evlist__mmap_per_evsel(struct perf_evlist *evlist, int idx,
return -1;

+ perf_evlist__add_pollfd(evlist, fd);
if ((evsel->attr.read_format & PERF_FORMAT_ID) &&
perf_evlist__id_add_fd(evlist, evsel, cpu, thread, fd) < 0)
return -1;

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