updates 2.9 Bookworm

now I have a buster on one machine, on another bookworm. latency 2 times in favor of the buster. Motherboards and the rest are the same. dealing with settings...

I wish the bookworm latency issues would get dialed in and sorted, seems it keeps getting worse and worse with each new kernel release. the latest (6.1.0-15) was awful, I had to revert back to 6.1.0-13 because the machine wanted to shake itself apart when I tried to home and it started popping up latency warnings. what a mess! seems like someone could identify the issues and iron them out, i imagine many folks, myself included would be grateful to get the latency we were seeing back in debian stretch.

Version 6.1.67-rt20 of the real time kernel was released today but it will take a while before it is available in Debian (if at all)

Brief instructions to install mentioned with the release
Or to build 6.1.67-rt20 directly, the following patches should be applied:

   www.kernel.org/pub/linux/kernel/v6.x/linux-6.1.tar.xz

   www.kernel.org/pub/linux/kernel/v6.x/patch-6.1.67.xz

   www.kernel.org/pub/linux/kernel/projects...6.1.67-rt20.patch.xz

 

Lcvette wrote:

I wish the bookworm latency issues would get dialed in and sorted.
 

I've managed to dial my latency down to +/-0.04ms with ethtool. Contrary to the infamous hardware-irq-coalesce-rx−usecs 0 documented (this 0 didn't worked for me, made things worst in fact), some tuning/testing is required. 

Using ethtool --coalesce
$ sudo apt install ethtool
$ sudo ethtool -c eth0
( take notes of your rx-usecs and tx-usecs defaults. Mine were 100 and 1000 respectively)
( start Linuxcnc and have it connected to the card)
( Time to dial/tune)

$ sudo ethtool -C eth0 rx-usecs 50
$ sudo ethtool -C eth0 tx-usecs 500
$ ping ip.ip.ip.ip
....
$ sudo ethtool -C eth0 rx-usecs 25
$ sudo ethtool -C eth0 tx-usecs 250
$ ping ip.ip.ip.ip
....
( Repeat tuning until you get satisfactory latency and no lcnc task/axis pos errors, etc. )
( Once everyone's happy, save those in your interface conf. )

$ sudo nano /etc/network/interfaces

***********************************************
      # The loopback network interface
      auto lo
      iface lo inet loopback

      auto eth0
      iface eth0 inet static
      (... ... static address stuff)
      hardware-irq-coalesce-rx−usecs 25
      hardware-irq-coalesce-tx−usecs 250
***********************************************

$ sudo systemctl restart networking

Serg452 wrote:

Key at buildbot2.highlab.com/debian/dists/bookworm/
Current: 2.9.0-88-g6ded497531

Lcvette wrote:

I wish the bookworm latency issues would get dialed in and sorted.
 
I've managed to dial my latency down to +/-0.04ms with ethtool. Contrary to the infamous hardware-irq-coalesce-rx−usecs 0 documented (this 0 didn't worked for me, made things worst in fact), some tuning/testing is required. 

Using ethtool --coalesce
$ sudo apt install ethtool
$ sudo ethtool -c eth0
( take notes of your rx-usecs and tx-usecs defaults. Mine were 100 and 1000 respectively)
( start Linuxcnc and have it connected to the card)
( Time to dial/tune)

$ sudo ethtool -C eth0 rx-usecs 50
$ sudo ethtool -C eth0 tx-usecs 500
$ ping ip.ip.ip.ip
....
$ sudo ethtool -C eth0 rx-usecs 25
$ sudo ethtool -C eth0 tx-usecs 250
$ ping ip.ip.ip.ip
....
( Repeat tuning until you get satisfactory latency and no lcnc task/axis pos errors, etc. )
( Once everyone's happy, save those in your interface conf. )

$ sudo nano /etc/network/interfaces

***********************************************
      # The loopback network interface
      auto lo
      iface lo inet loopback

      auto eth0
      iface eth0 inet static
      (... ... static address stuff)
      hardware-irq-coalesce-rx−usecs 25
      hardware-irq-coalesce-tx−usecs 250
***********************************************

$ sudo systemctl restart networking

 

thanks,  I will give that a try and report back!