Re: [RFC PATCH 5/6] bpf: Implement function bpf_read_pmu() that get the selected hardware PMU conuter

Peter Zijlstra
2015-07-17T11:55:16Z

On Fri, Jul 17, 2015 at 07:45:02PM +0800, Wangnan (F) wrote:

> >Depends on what all you need, if you need full perf events to work then
> >yes perf_event_read_value() is your only option.
> >
> >But note that that requires scheduling, so you cannot actually use it
> >for tracing purposes etc..

> What you mean "full perf events"? Even with your code some event still not
> work?

The code I posted only works for events that do not have inherit set.
And only works from IRQ/NMI context for events that monitor the current
task or the current CPU (although that needs a little extra code still).

Anything else and it does not work (correctly).