netdev - Re: [PATCH net-next v2 2/2] net: Check skb->rxhash in gro

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Date:	Tue, 14 Jan 2014 16:20:26 -0800
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Tom Herbert <therbert@...gle.com>
Cc:	davem@...emloft.net, netdev@...r.kernel.org
Subject: Re: [PATCH net-next v2 2/2] net: Check skb->rxhash in gro_receive

On Tue, 2014-01-14 at 16:02 -0800, Tom Herbert wrote:
> When initializing a gro_list for a packet, first check the rxhash of
> the incoming skb against that of the skb's in the list. This should be
> a very strong inidicator of whether the flow is going to be matched,
> and potentially allows a lot of other checks to be short circuited.
> Use skb_hash_noeval so that we don't force the hash to be calculated.
> 
> Tested by running netperf 200 TCP_STREAMs between two machines with
> GRO, HW rxhash, and 1G. Saw no performance degration, slight reduction
> of time in dev_gro_receive.
> 
> Signed-off-by: Tom Herbert <therbert@...gle.com>
> ---
>  net/core/dev.c | 9 ++++++++-
>  1 file changed, 8 insertions(+), 1 deletion(-)

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


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