[PATCH 2/5] perf record: Fix done_fd wakeup event

From: Adrian Hunter
Date: Wed Aug 24 2022 - 03:28:55 EST


evlist__add_wakeup_eventfd() calls perf_evlist__add_pollfd() to add a
non-perf-event to the evlist pollfds. Since commit 415ccb58f68a
("perf record: Introduce thread specific data array") that doesn't work
because evlist pollfs is not polled and done_fd is not duplicated into
thread-data.

Patch "perf record: Fix way of handling non-perf-event pollfds" added a new
approach that ensures file descriptors like done_fd are handled correctly
by flagging them as fdarray_flag__non_perf_event.

Fix by flagging done_fd as fdarray_flag__non_perf_event.

Example:

Before:

$ sleep 3 & perf record -vv -p $!
...
thread_data[0x55f44bd34140]: pollfd[0] <- event_fd=5
thread_data[0x55f44bd34140]: pollfd[1] <- event_fd=6
thread_data[0x55f44bd34140]: pollfd[2] <- event_fd=7
thread_data[0x55f44bd34140]: pollfd[3] <- event_fd=8
thread_data[0x55f44bd34140]: pollfd[4] <- event_fd=9
thread_data[0x55f44bd34140]: pollfd[5] <- event_fd=10
thread_data[0x55f44bd34140]: pollfd[6] <- event_fd=11
thread_data[0x55f44bd34140]: pollfd[7] <- event_fd=12
...

After:

$ sleep 3 & perf record -vv -p $!
...
thread_data[0x55a8ded89140]: pollfd[0] <- event_fd=5
thread_data[0x55a8ded89140]: pollfd[1] <- event_fd=6
thread_data[0x55a8ded89140]: pollfd[2] <- event_fd=7
thread_data[0x55a8ded89140]: pollfd[3] <- event_fd=8
thread_data[0x55a8ded89140]: pollfd[4] <- event_fd=9
thread_data[0x55a8ded89140]: pollfd[5] <- event_fd=10
thread_data[0x55a8ded89140]: pollfd[6] <- event_fd=11
thread_data[0x55a8ded89140]: pollfd[7] <- event_fd=12
thread_data[0x55a8ded89140]: pollfd[8] <- non_perf_event fd=4
...

This patch depends on "perf record: Fix way of handling non-perf-event
pollfds".

Fixes: 415ccb58f68a ("perf record: Introduce thread specific data array")
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
tools/perf/util/evlist.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/evlist.c b/tools/perf/util/evlist.c
index 48167f3941a6..0b2222d05577 100644
--- a/tools/perf/util/evlist.c
+++ b/tools/perf/util/evlist.c
@@ -608,7 +608,8 @@ int evlist__filter_pollfd(struct evlist *evlist, short revents_and_mask)
int evlist__add_wakeup_eventfd(struct evlist *evlist, int fd)
{
return perf_evlist__add_pollfd(&evlist->core, fd, NULL, POLLIN,
- fdarray_flag__nonfilterable);
+ fdarray_flag__nonfilterable |
+ fdarray_flag__non_perf_event);
}
#endif

--
2.25.1