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. 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.
