linux-kernel - Re: [PATCH 8/7] net/netfilter/nf_conntrack

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Message-ID: <20160906175648.GC29382@arm.com>
Date:   Tue, 6 Sep 2016 18:56:48 +0100
From:   Will Deacon <will.deacon@....com>
To:     Manfred Spraul <manfred@...orfullife.com>
Cc:     Peter Zijlstra <peterz@...radead.org>, benh@...nel.crashing.org,
        paulmck@...ux.vnet.ibm.com, Ingo Molnar <mingo@...e.hu>,
        Boqun Feng <boqun.feng@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        LKML <linux-kernel@...r.kernel.org>, 1vier1@....de,
        Davidlohr Bueso <dave@...olabs.net>,
        Pablo Neira Ayuso <pablo@...filter.org>,
        netfilter-devel@...r.kernel.org
Subject: Re: [PATCH 8/7] net/netfilter/nf_conntrack_core: Remove another
 memory barrier

On Mon, Sep 05, 2016 at 08:57:19PM +0200, Manfred Spraul wrote:
> On 09/02/2016 09:22 PM, Peter Zijlstra wrote:
> Anyone around with a ppc or arm? How slow is the loop of the
> spin_unlock_wait() calls?
> Single CPU is sufficient.
> 
> Question 1: How large is the difference between:
> #./sem-scalebench -t 10 -c 1 -p 1 -o 4 -f -d 1
> #./sem-scalebench -t 10 -c 1 -p 1 -o 4 -f -d 256
> https://github.com/manfred-colorfu/ipcscale

Not sure exactly what you want me to run here, but with an arm64
defconfig -rc3 kernel, those two invocations give me "Max total" values
where the first is 20x bigger than the second.

Will