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From: Christoph Mathys <eraserix@gmail.com>
To: linux-rt-users@vger.kernel.org
Subject: Network latency on 5.4 and 5.10
Date: Thu, 20 May 2021 09:36:46 +0200	[thread overview]
Message-ID: <6aa61bb9-0443-6da3-0902-9fe700c24017@gmail.com> (raw)

Hi all!

I'm trying to upgrade from 4.9-rt to 5.4-rt (also tried 5.10). I'm 
having a hard time getting networking to perform on the same level as 
4.9 (latency wise). We drive an EtherCAT bus at 4kHz using the igb driver.

On 4.9, I just had to disable coalescing on the nic and increase the 
priority of the irg threads and it performed as desired (more or less 
according to [1] for 3.6+ without task pinning)

Doing the same on 5.4/5.10 does not seem to suffice any more. I get a 
lot of warnings from our code that packets have not been sent or 
received in time for the next control loop iteration.

Any suggestions on what I could try to improve the nic response?

Thanks!
Christoph

[1] 
https://www.osadl.org/Real-time-Ethernet-UDP-worst-case-roun.qa-farm-rt-ethernet-udp-monitor+M514ebdffa90.0.html

             reply	other threads:[~2021-05-20  7:36 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-20  7:36 Christoph Mathys [this message]
2021-05-20  8:08 ` Network latency on 5.4 and 5.10 Christoph Mathys
2021-05-20 13:35 ` Peter C. Wallace
2021-05-25 14:30 ` Christoph Mathys
2021-05-26  3:23   ` chensong_2000
2021-05-26  6:10     ` Christoph Mathys
2021-05-26  7:15       ` chensong_2000
2021-05-31 15:16 ` Christoph Mathys

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