Messages in this thread | | | From | Vince Weaver <> | Date | Tue, 10 May 2016 23:33:13 -0400 (EDT) | Subject | Re: [RFC 2/2] perf/core: change errno for sampling event not supported in hardware |
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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
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