netdev - Re: [PATCH v2 net-next] Revert "net: init sk

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Date:   Tue, 24 Apr 2018 08:10:43 -0700
From:   Eric Dumazet <eric.dumazet@...il.com>
To:     Yafang Shao <laoar.shao@...il.com>, eric.dumazet@...il.com,
        davem@...emloft.net
Cc:     netdev@...r.kernel.org
Subject: Re: [PATCH v2 net-next] Revert "net: init sk_cookie for inet socket"



On 04/24/2018 08:07 AM, Yafang Shao wrote:
> This reverts commit <c6849a3ac17e> ("net: init sk_cookie for inet socket")
> 
> Per discussion with Eric, when update sock_net(sk)->cookie_gen, the
> whole cache cache line will be invalidated, as this cache line is shared
> with all cpus, that may cause great performace hit.
> 
> Bellow is the data form Eric.
> "Performance is reduced from ~5 Mpps to ~3.8 Mpps with 16 RX queues on
> my host" when running synflood test.
> 
> Have to revert it to prevent from cache line false sharing.
> 
> Signed-off-by: Yafang Shao <laoar.shao@...il.com>

Reviewed-by: Eric Dumazet <edumazet@...gle.com>

Thanks !