perf_event wakeup_events = 0

[Valdis Kl=?utf-8?Q?=c4=93?=tnieks]

On Sat, 07 Sep 2019 09:14:49 -0700, Theodore Dubois said:

> If I’m reading this right, this is a sampling event which overflows 4000
> times a second. But perf then does a poll call which wakes up on this FD with
> POLLIN after 1.637 seconds, instead of 0.00025 seconds.

No, it *takes a sample* 4,000 times a second.  For instance, number of cache line
misses since the last sample.  You get an overflow when the counter wraps because
there have been more than 2^32 events since you read the counter.

At least that's my understanding of it.
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