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Subject: Re: [PATCH 07/17] net: convert sock.sk_refcnt from atomic_t to
 refcount_t
From: Eric Dumazet <eric.dumazet@gmail.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Herbert Xu <herbert@gondor.apana.org.au>,
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Date: Mon, 20 Mar 2017 09:34:44 -0700
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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.