MINOR: activity: report the number of times poll() reports I/O
The "show activity" output mentions a number of indicators to explain
wake up reasons but doesn't have the number of times poll() sees some
I/O. And given that multiple events can happen simultaneously, it's
not always possible to deduce this metric by subtracting.
This patch adds a new "poll_io" counter that allows one to see how
often poll() returns with at least one active FD. This should help
detect stuck events and measure various ratios of poll sub-metrics.
diff --git a/src/ev_epoll.c b/src/ev_epoll.c
index 2501dd5..e5437a2 100644
--- a/src/ev_epoll.c
+++ b/src/ev_epoll.c
@@ -180,8 +180,10 @@
status = epoll_wait(epoll_fd[tid], epoll_events, global.tune.maxpollevents, timeout);
tv_update_date(timeout, status);
- if (status)
+ if (status) {
+ activity[tid].poll_io++;
break;
+ }
if (timeout || !wait_time)
break;
if (signal_queue_len || wake)