I have just done some updates while running 3.8.0-0.rc5.git0.1.fc19. A couple
of these machines were booted with slub_debug=- . They all seemed a bit
slower (based on my watching the updates and not real benchmarks) than with
with the previous debug kernels. It isn't quite to show stopping slow, but
it's getting close. It might be the slowness I see with debugging
kernels for yum updates, is due to a combination of multiple debugging
features rather than a single one.