netdev - Re: Poor thunderbolt-net interface performance when bridged

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Message-Id: <A68375CA-57E1-4F53-877D-480231F07942@bejarano.io>
Date: Tue, 2 Sep 2025 12:18:59 +0200
From: Ricard Bejarano <ricard@...arano.io>
To: Ido Schimmel <idosch@...sch.org>
Cc: Andrew Lunn <andrew@...n.ch>,
 Mika Westerberg <mika.westerberg@...ux.intel.com>,
 netdev@...r.kernel.org,
 michael.jamet@...el.com,
 YehezkelShB@...il.com,
 andrew+netdev@...n.ch,
 davem@...emloft.net,
 edumazet@...gle.com,
 kuba@...nel.org,
 pabeni@...hat.com
Subject: Re: Poor thunderbolt-net interface performance when bridged

Hi Ido,

Thanks for your reply!

I'm afraid we don't just see it with TCP or with bridged traffic. That was my
original observation and so the title of the thread, but it happens at a much
lower level, at the data link layer. We observed CRC checksum failures in link
stats. You can see those in my May 27th message in the thread.

The last thing we tried was to force linearization of SKBs with fragments, to
see if the problem is with how the driver puts those on the line, which might
offset everything out of its place, making CRC checksums fail. I was not able
to do it, however, as that would simply hang all my tests.

Any ideas?

Thanks,
Ricard Bejarano