On Tue, Mar 21, 2017 at 04:51:13PM -0700, Kees Cook wrote: > On Tue, Mar 21, 2017 at 2:23 PM, Eric Dumazet <eric.dumazet@xxxxxxxxx> wrote: > > Unfortunately there is no good test simulating real-world workloads, > > which are mostly using TCP flows. > > Sure, but there has to be _something_ that can be used to test to > measure the effects. Without a meaningful test, it's weird to reject a > change for performance reasons. This. How can you optimize if there's no way to actually measure something? > > Most synthetic tools you can find are not using epoll(), and very often > > hit bottlenecks in other layers. > > > > > > It looks like our suggestion to get kernel builds with atomic_inc() > > being exactly an atomic_inc() is not even discussed or implemented. > > So, FWIW, I originally tried to make this a CONFIG in the first couple > passes at getting a refcount defense. I would be fine with this, but I > was not able to convince Peter. :) However, things have evolved a lot > since then, so perhaps there are things do be done here. Well, the argument was that unless there's a benchmark that shows it cares, its all premature optimization. Similarly, you wanted this enabled at all times because hardening.
