PThread profiling

[Frank Ch. Eigler]

Josh Stone <jistone@redhat.com> writes:

>> It worked fine, but the overhead was causing measurements errors
>> (too slow == higher contention probability). It was clear that I
>> had to use static markers, all I had to do was patch glibc/nptl
>> and voila.
>
> Can you share performance numbers on this?  I'd like to see the
> comparison of unprobed, function uprobes, and static markers...

Since user-space static markers are currently implemented in terms of
uprobes, it should not assist performance.  We may devise a different
method to jump to the kernel-side handler (e.g., some creatively
misused system call/signal that we can catch via utrace/kprobes), at
which point it could get much faster.

- FChE