LinuxCNC on Raspberry Pi 5

I have tried several CAT cables (5, 5e, 6) between Pi 5 and 7i96s and it seems that ethernet comms just stops after some short period of time.

(I am using CAT 6 below.)

Whenever it stops, the green ethernet connector LEDs both remain steady ON (they flash during data transfer).

Once they are steady ON, PINGing the 7i96s results in no reply.

cnc@linuxcnc:/usr/sbin$ sudo chrt 99 ping -i .001 -q 10.10.10.10
PING 10.10.10.10 (10.10.10.10) 56(84) bytes of data.

--- 10.10.10.10 ping statistics ---
94246 packets transmitted, 93613 received, 0.671647% packet loss, time 100046ms
rtt min/avg/max/mdev = 0.101/0.113/0.286/0.007 ms
^Ccnc@linuxcnc:/usr/sbinping-q 10.10.10.10
PING 10.10.10.10 (10.10.10.10) 56(84) bytes of data.

Initially there was only 1 packet loss (approx. 1 in 30,000), then the ethernet comms stopped and the packet loss is obviously 100% after that.

WHILE I AM TYPING THIS the comms surprisingly just restarted, indicated by the ping commands receiving a reply.

And after about 100 pings, comms stopped again (both green LEDs steady ON.

And a few minutes later the pings have started again

It would be prudent to disable EEE in the kernel with  the boot parameter I mentioned.
From what I read, some cards it is always on and they do not respect the ethtool settings anyway.
Networking Including the ethercat generic driver is not real time 
Ethercat has a very limited range of network drivers that are real time, but I don't think they are distributed in their debs. YOU need to build fro  source (please check me here as I might be wrong)

Any packet loss means serious driver/hardware issues.
I would not expect to see any loss even after weeks of uptime.

After a bit of poking around, I found a directory

/boot/broadcom

which contains a lot of files including

cmdline.txt

and

config.txt

I have added the igb.EEE=0 to the end of cmdline.txt as this has "isolcpus" in it.

Full file =

console=serial0,115200 console=tty1 root=PARTUUID=486f86bd-02 rootfstype=ext4 fsck.repair=yes loglevel=5 net.ifnames=0 processor.max_cstate=1 isolcpus=2,3 firmware_class.path=/lib/firmware/updates/brcm rootwait cfg80211.ieee80211_regdom=NZ igb.EEE=0

Will now reboot...

Here is part of dmesg.

[    0.000000] Kernel command line: coherent_pool=1M 8250.nr_uarts=1 pci=pcie_bus_safe snd_bcm2835.enable_compat_alsa=0 snd_bcm2835.enable_hdmi=1 bcm2708_fb.fbwidth=1920 bcm2708_fb.fbheight=1080 bcm2708_fb.fbdepth=16 bcm2708_fb.fbswap=1 smsc95xx.macaddr=D8:3A:DD:E8:87:4E vc_mem.mem_base=0x3fc00000 vc_mem.mem_size=0x40000000  console=ttyAMA10,115200 console=tty1 root=PARTUUID=486f86bd-02 rootfstype=ext4 fsck.repair=yes loglevel=5 net.ifnames=0 processor.max_cstate=1 isolcpus=2,3 firmware_class.path=/lib/firmware/updates/brcm rootwait cfg80211.ieee80211_regdom=NZ igb.EEE=0

dmesg | grep EEE shows only the line above (e.g. no errors with EEE in them).

I think this is particularly concerning. The ethernet connection just seems unstable. As pointed out, there simply should not be packet loss.

I will try replacing the Pi 5 with a PC tomorrow to trying eliminating the 7i96s as part of the problem.

cnc@linuxcnc:~/Downloads/7i96s/configs/hostmot2$ sudo chrt 99 ping -i .001 -q 10.10.10.10
PING 10.10.10.10 (10.10.10.10) 56(84) bytes of data.

--- 10.10.10.10 ping statistics ---
7234 packets transmitted, 7233 received, 0.0138236% packet loss, time 7240ms
rtt min/avg/max/mdev = 0.101/0.106/0.132/0.002 ms

Replaced RPi 5 with HP desktop running LinuxCNC 0.29.1, connected to 7i96s over CAT6 cable.

sudo chrt 99 ping -i .001 -q 10.10.10.10

Quick test shows 0% packet loss for 40,000 packets.

And a longer test:

2312351 sent, 2312350 received  <<<<<<<  Loss of 1 packet

rtt min/avg/max/mdev = 0.177/0.266/0.455/0.019 ms