Em Tue, Feb 16, 2016 at 07:10:37PM -0800, Andi Kleen escreveu: > > Need to investigate why there are kernel samples when --all-user is used and > > the other way around as well.
> This is a known issue due to skid. PEBS usually avoids it. Right, thanks for pointing this out, we have to detect that :p is not being used and warn the user about this possibility, i.e. user asks for just kernel samples, tool finds user samples, tell that using :p+ may help. Now, using plain: # perf record --all-user -a sleep 2 will make it use the default which is 'cycles' with the highest precision available on the machine, and that leaves just a few samples that supposedly have the MISC_KERNEL bit set in the perf_event_attr header, those are not mapping to any mmap area known to the tool, I'm investigating what this is. I'll apply the patch as-is, we'll check later OPT_ magic to tell that those options are mutually exclusive. - Arnaldo