On Wed, Aug 7, 2019, at 12:03 PM, Andrii Nakryiko wrote: > On Tue, Aug 6, 2019 at 4:39 PM Daniel Xu <dxu@xxxxxxxxx> wrote: > > > > It's useful to know kprobe's nmissed and nhit stats. For example with > > Is nmissed/nhit kprobe-specific? What about tracepoints and raw > tracepoints, do they have something similar or they can never be > missed? At least nhit still seems useful, so would be nice to have > ability to get that with the same API, is it possible? > I'm still trying to grok all the tracepoint/ftrace machinery, but it appears to me like it is kprobe/uprobe specific. My guess is that b/c tracepoints are inline (and don't require trapping interrupts), it cannot really "miss". This brings up a good point, though. I think we want the same querying functionality for uprobes so it might be worthwhile to make this API generic. Something like PERF_EVENT_IOC_QUERY_PROBE so we can later add in uprobe stats. And maybe tracepoint if it makes sense. Thoughts?
