Confused about wakeup watermark vs sample period when attaching to BPF program

Hayden Livingston

Please correct me if I'm wrong about anything.

When a perf_event is attached to a BPF program and the BPF program is
going to do processing and then output what is the significant of
wakeup_events or wakeup_watermark for the original perf_event?

To me it seem like it BPF program will always run, but in the absence
of mmap buffer in original perf_event does it matter?

Then also, what should I set my BPF_OUTPUT wakeup to? Should I set to
large number? How can I get notified in my BPF OUTPUT (not the
original perf) after every 5 seconds? Is that possible?