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 ? -Vineet > > The original change from ENODEV to ENOTSUPP managed to break things > although it took four kernel releases before anyone noticed. > > The usage of ENOTSUPP was my fault, though I feel like at the time I was > told that ENOTSUPP is for internal kernel usage and would be converted to > EOPNOTSUPP when returning an error to userspace. But now I > can't find any sort of reference for that at all, except the fact that > > /usr/include/x86_64-linux-gnu/bits/errno.h > > has > /* Linux has no ENOTSUP error code. */ > # define ENOTSUP EOPNOTSUPP > > in it... but wait, that's ENOTSUP not ENOTSUPP. Blargh. > > Vince >
