Re: [PATCH v3 bpf-next 1/4] tracing/probe: Add PERF_EVENT_IOC_QUERY_PROBE ioctl

From: Peter Zijlstra
Date: Tue Aug 20 2019 - 10:45:14 EST

On Fri, Aug 16, 2019 at 03:31:46PM -0700, Daniel Xu wrote:
> It's useful to know [uk]probe's nmissed and nhit stats. For example with
> tracing tools, it's important to know when events may have been lost.
> debugfs currently exposes a control file to get this information, but
> it is not compatible with probes registered with the perf API.

What is this nmissed and nhit stuff?