[RFC PATCH 1/2] percpu_counter: Allow falling back to global counter on large system

[Christoph Lameter]

On Wed, 16 Mar 2016, Waiman Long wrote:

> > If the cpumask is empty you can use the global count. Otherwise you just
> > need to add up the counters of the cpus set in the cpumask.
> >
>
> I have modified the patch to try that out. However, that doesn't yield that
> much of improvement in term of performance and it slows down the percpu fast
> path a bit. So I am going to focus on my existing patch first and think about
> that later.

Hmmm... Maybe look at the cause of the slowdown first?