On Wed, Oct 9, 2019 at 3:20 AM Jesper Dangaard Brouer <brouer@xxxxxxxxxx> wrote: > > > The change Toke did in BPF_PROG_RUN does not introduce any measurable > performance change, as least on high-end Intel CPUs. This DOES satisfy > 'no performance regressions' rule. It adds extra load and branch in critical path of every program. Including classic socket filters. Not being able to measure the overhead in a microbenchmark doesn't mean that overhead is not added. Will 10 such branches be measurable? What if they're not? Then everyone will say: "It's not measurable in my setup, hence I'm adding these branches". tcp stack is even harder to measure. Yet, Eric will rightfully nack patches that add such things when alternative solution is possible.
