[Bridge] [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to refcount_t

[Eric Dumazet]

On Mon, 2017-03-20 at 09:18 -0700, Eric Dumazet wrote:

> Interesting.
> 
> UDP ipv4 xmit path gets a ~25 % improvement on PPC with this patch.
> 
> ( 20 concurrent netperf -t UDP_STREAM  : 2.45 Mpps -> 3.07 Mpps )

Well, there _is_ a difference, but not 25 % (this was probably caused by
different queues on TX or RX between my reboots).

I added a sysctl hack to be able to dynamically change on a given
workload, and we hit other bottlenecks (mainly qdisc locks and driver tx
locks) anyway.