netdev - Re: [PATCH net-next v2] af-packet: new flag to indicate all csums are good

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Message-ID: <7ce5ae2a-4bce-99af-4fd7-900e6caa8f89@inliniac.net>
Date:   Tue, 2 Jun 2020 21:47:10 +0200
From:   Victor Julien <victor@...iniac.net>
To:     Jakub Kicinski <kuba@...nel.org>
Cc:     Willem de Bruijn <willemdebruijn.kernel@...il.com>,
        Network Development <netdev@...r.kernel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Jonathan Corbet <corbet@....net>,
        Eric Dumazet <edumazet@...gle.com>,
        Mao Wenan <maowenan@...wei.com>, Arnd Bergmann <arnd@...db.de>,
        Neil Horman <nhorman@...driver.com>, linux-doc@...r.kernel.org,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Alexander Drozdov <al.drozdov@...il.com>,
        Tom Herbert <tom@...bertland.com>
Subject: Re: [PATCH net-next v2] af-packet: new flag to indicate all csums are
 good

On 02-06-2020 21:29, Jakub Kicinski wrote:
> On Tue, 2 Jun 2020 21:22:11 +0200 Victor Julien wrote:
>> - receiver uses nfp (netronome) driver: TP_STATUS_CSUM_VALID set for
>> every packet, including the bad TCP ones
>> - receiver uses ixgbe driver: TP_STATUS_CSUM_VALID not set for the bad
>> packets.
>>
>> Again purely based on 'git grep' it seems nfp does not support
>> UNNECESSARY, while ixgbe does.
>>
>> (my original testing was with the nfp only, so now I at least understand
>> my original thinking)
> 
> FWIW nfp defaults to CHECKSUM_COMPLETE if the device supports it (see
> if you have RXCSUM_COMPLETE in the probe logs). It supports UNNECESSARY
> as well, but IDK if there is a way to choose  the preferred checksum
> types in the stack :( You'd have to edit the driver and remove the
> NFP_NET_CFG_CTRL_CSUM_COMPLETE from the NFP_NET_CFG_CTRL_RXCSUM_ANY
> mask to switch to using UNNECESSARY.
> 

I indeed have RXCSUM_COMPLETE, so that should mean it uses
CHECKSUM_COMPLETE indeed.

nfp 0000:43:00.0 eth0: CAP: 0x78140233 PROMISC RXCSUM TXCSUM GATHER TSO2
RSS2 AUTOMASK IRQMOD RXCSUM_COMPLETE

-- 
---------------------------------------------
Victor Julien
http://www.inliniac.net/
PGP: http://www.inliniac.net/victorjulien.asc
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