On Wed, Jul 13, 2016 at 11:33 AM, Tejun Heo <t...@kernel.org> wrote: > On Wed, Jul 13, 2016 at 02:21:02PM -0400, Tejun Heo wrote: >> One interesting thing to try would be replacing it with a regular >> non-percpu rwsem and see how it behaves. That should easily tell us >> whether this is from actual contention or artifacts from percpu_rwsem >> implementation. > > So, something like the following. Can you please see whether this > makes any difference?
Yea. So this brings it down for me closer to what we're seeing with the Dmitry's patch reverting the two problematic commits, usually 10-50us with one early spike at 18ms. thanks -john
