From: Lino Sanfilippo <LinoSanfilippo@gmx.de>
To: Vladimir Oltean <olteanv@gmail.com>
Cc: Andrew Lunn <andrew@lunn.ch>,
woojung.huh@microchip.com, UNGLinuxDriver@microchip.com,
vivien.didelot@gmail.com, f.fainelli@gmail.com,
davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Aw: Re: [PATCH 2/2] net: dsa: tag_ksz: dont let the hardware process the layer 4 checksum
Date: Thu, 15 Jul 2021 15:04:31 +0200 [thread overview]
Message-ID: <trinity-0dbbc59b-1e7d-4f58-8611-adb281a82477-1626354270982@3c-app-gmx-bap31> (raw)
In-Reply-To: <20210715114908.ripblpevmdujkf2m@skbuf>
> Gesendet: Donnerstag, 15. Juli 2021 um 13:49 Uhr
> Von: "Vladimir Oltean" <olteanv@gmail.com>
> An: "Lino Sanfilippo" <LinoSanfilippo@gmx.de>
> Cc: "Andrew Lunn" <andrew@lunn.ch>, woojung.huh@microchip.com, UNGLinuxDriver@microchip.com, vivien.didelot@gmail.com, f.fainelli@gmail.com, davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org
> Betreff: Re: [PATCH 2/2] net: dsa: tag_ksz: dont let the hardware process the layer 4 checksum
>
> On Thu, Jul 15, 2021 at 01:16:12PM +0200, Lino Sanfilippo wrote:
> > Sure, I will test this solution. But I think NETIF_F_FRAGLIST should also be
> > cleared in this case, right?
>
> Hmm, interesting question. I think only hns3 makes meaningful use of
> NETIF_F_FRAGLIST, right? I'm looking at hns3_fill_skb_to_desc().
> Other drivers seem to set it for ridiculous reasons - looking at commit
> 66aa0678efc2 ("ibmveth: Support to enable LSO/CSO for Trunk VEA.") -
> they set NETIF_F_FRAGLIST and then linearize the skb chain anyway. The
> claimed 4x throughput benefit probably has to do with less skbs
> traversing the stack? I don't know.
>
> Anyway, it is hard to imagine all the things that could go wrong with
> chains of IP fragments on a DSA interface, precisely because I have so
> few examples to look at. I would say, header taggers are probably fine,
> tail taggers not so much, so apply the same treatment as for NETIF_F_SG?
>
Please note that skb_put() asserts that the SKB is linearized. So I think we
should rather clear both NETIF_F_FRAGLIST and NETIF_F_SG unconditionally since also
header taggers use some form of skb_put() dont they?
next prev parent reply other threads:[~2021-07-15 13:04 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-14 19:17 [PATCH 0/2] Fixes for KSZ DSA switch Lino Sanfilippo
2021-07-14 19:17 ` [PATCH 1/2] net: dsa: tag_ksz: linearize SKB before adding DSA tag Lino Sanfilippo
2021-07-14 19:17 ` [PATCH 2/2] net: dsa: tag_ksz: dont let the hardware process the layer 4 checksum Lino Sanfilippo
2021-07-14 19:48 ` Vladimir Oltean
2021-07-14 20:15 ` Andrew Lunn
2021-07-15 6:54 ` Vladimir Oltean
2021-07-15 11:16 ` Aw: " Lino Sanfilippo
2021-07-15 11:49 ` Vladimir Oltean
2021-07-15 13:04 ` Lino Sanfilippo [this message]
2021-07-15 13:12 ` Vladimir Oltean
2021-07-15 13:34 ` Aw: " Lino Sanfilippo
2021-07-15 13:08 ` Andrew Lunn
2021-07-15 14:36 ` Vladimir Oltean
2021-07-15 15:50 ` Andrew Lunn
2021-07-19 8:20 ` Aw: " Lino Sanfilippo
2021-07-19 8:24 ` Vladimir Oltean
2021-07-15 16:24 ` Florian Fainelli
2021-07-15 23:23 ` [PATCH 0/2] Fixes for KSZ DSA switch Florian Fainelli
2021-07-16 8:49 ` Aw: " Lino Sanfilippo
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