Re: [PATCH 09/17] perf tools: Detect avalibility of write_backward

[Wangnan (F)]

On 2016/5/13 21:08, Arnaldo Carvalho de Melo wrote:
> Em Fri, May 13, 2016 at 07:56:06AM +0000, Wang Nan escreveu:
> > Detect avalibility of write_backward and save the result into
> > record_opts. With write_backward the start pointer of a ring
> > buffer mapped read only can be found reliably.
> We have perf_missing_features for that, please try to use it.

I'll try it, but write_backward can't fallback, if kernel doesn't
support it, I think we'd better throw an error earlier. Using
perf_missing_features we get error during opening the event, so if we want
to fail earlier we still need API probing.

Thank you.