On Wed, Mar 22, 2017 at 07:54:04AM -0700, Eric Dumazet wrote: > On Wed, 2017-03-22 at 15:33 +0100, Peter Zijlstra wrote: > > > > > But I would feel a whole lot better about the entire thing if we could > > measure their impact. It would also give us good precedent to whack > > other potential users of _nocheck over the head with -- show numbers. > > I wont be able to measure the impact on real workloads, our productions > kernels are based on 4.3 at this moment.
Is there really no micro bench that exercises the relevant network paths? Do you really fully rely on Google production workloads? > I guess someone could code a lib/test_refcount.c launching X threads > using either atomic_inc or refcount_inc() in a loop. > > That would give a rough estimate of the refcount_t overhead among > various platforms. Its also a fairly meaningless number. It doesn't include any of the other work the network path does.
