perf_event wakeup_events = 0

[Theodore Dubois]

The man page for perf_event_open(2) says that recent kernels treat a 0
value for wakeup_events the same as 1, which I believe means it will
notify after a single sample. However, strace on perf(1) shows that it
uses wakeup_events=0, and it's definitely not waking up on every
sample (it seems to be waking up every few seconds.)
tools/perf/design.txt says "Normally a notification is generated for
every page filled". Is the documentation wrong, or am I
misunderstanding something?

~Theodore