netdev - Re: Bad performance in RX with sfc 40G

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Date:   Thu, 2 Dec 2021 15:26:25 +0100
From:   Íñigo Huguet <ihuguet@...hat.com>
To:     Eric Dumazet <eric.dumazet@...il.com>
Cc:     Edward Cree <ecree.xilinx@...il.com>, habetsm.xilinx@...il.com,
        netdev@...r.kernel.org, Dinan Gunawardena <dinang@...inx.com>,
        Pablo Cascon <pabloc@...inx.com>
Subject: Re: Bad performance in RX with sfc 40G

Hi,

On Thu, Nov 18, 2021 at 6:19 PM Eric Dumazet <eric.dumazet@...il.com> wrote:
> You could try to :
>
> Make the RX ring buffers bigger (ethtool -G eth0 rx 8192)
>
> and/or
>
> Make sure your tcp socket receive buffer is smaller than number of frames in the ring buffer
>
> echo "4096 131072 2097152" >/proc/sys/net/ipv4/tcp_rmem

Thanks for the suggestion. Sadly, the results are almost the same.

> You can also try latest net-next, as TCP got something to help this case.
>
> f35f821935d8df76f9c92e2431a225bdff938169 tcp: defer skb freeing after socket lock is released

I'll try ASAP, but I will need some days. Thanks



-- 
Íñigo Huguet