On Mon, 9 May 2016, Vineet Gupta wrote: > On Monday 09 May 2016 07:24 PM, Vince Weaver wrote: > > On Mon, 9 May 2016, Vineet Gupta wrote: > > > >> This allows userspace to identify this case specifically from the > >> catch all error msg it prints currently. > >> > >> This is an ABI change > > > > An ABI change which will probably break things. > > > Right thats what I feared. But hold on, I don't think we need to change the ABI to > achieve what we want. Gosh why did I even take that path. > > Currently the errno switch case in perf_evsel__open_strerror() in doesn't handle > ENOTSUPP. So how about we add that - augmented with the same sample_period !0 > check to barf for lack of sampling support. > > Do you see anything wrong with that ? no, but it would be nice if one of the actual maintainers would chime in with an opinion. In any case if ENOTSUPP is being returned to userspace I should update the perf_event manpage to reflect that. Vince
