latency (netowork?) 7010 with 7i96s+7i84u

I'm setting up a new system and I'm sometimes getting a unexpected realtime delay on task 0 with period 1000000 error (mostly on startup) and there was a few error finishing read ones as well. After much reading and tinkering I've got it to this point and I'm not sure if it's OK or not.
7010, all the extra anything in the bios has been turned off, only using the 1 core
built in intel network controller, onboard graphics
Ping 192.168.1.121 was up around 350ms, made the changes to the networks file and it is about 150ms now, mainly sits just under 100ms so I think the network to card connection is ok.
Histogram looks pretty "fat" though ???
Also had a tri-peak at one point... might have been a glitch though
Is it safe to just bump the period up some or is there something I can actually do to make this better

M
 

I ran it a couple of times
cnc@router:~$ sudo chrt 99 ping -i .001 -q -c 60000 192.168.1.121
PING 192.168.1.121 (192.168.1.121) 56(84) bytes of data.
--- 192.168.1.121 ping statistics ---
60000 packets transmitted, 60000 received, 0% packet loss, time 59999ms
rtt min/avg/max/mdev = 0.074/0.086/0.256/0.008 ms
cnc@router:~$ sudo chrt 99 ping -i .001 -q -c 60000 192.168.1.121

PING 192.168.1.121 (192.168.1.121) 56(84) bytes of data.
--- 192.168.1.121 ping statistics ---
60000 packets transmitted, 60000 received, 0% packet loss, time 59999ms
rtt min/avg/max/mdev = 0.074/0.086/0.377/0.008 ms

The histogram l ran on it's own and with 5 gears running

The i5 3470 is a four core chip.

Might be worth checking your BIOS to see if there is a setting that either enables or disables the 4 cores.

Right now I've got it turned down to only a single. One of the many documents on tuning I came across seemed to want the 7010 to run with it set to single. I'll reset it to all in the bios and re-post


--- 192.168.1.121 ping statistics ---
60000 packets transmitted, 60000 received, 0% packet loss, time 59999ms
rtt min/avg/max/mdev = 0.065/0.102/0.281/0.018 ms

M

 

I would use all cores but set isolcpus=3  in the kernel command line
otherwise you run all realtime and non-realtime code on the one core.
(plus reducing overall performance)

In addition, pinning the Ethernet IRQ to the last CPU (LinuxCNCs CPU)
will help with network latency.
 

altered the grub
GRUB_DEFAULT=0
GRUB_TIMEOUT=5
GRUB_DISTRIBUTOR=`lsb_release -i -s 2> /dev/null || echo Debian`
GRUB_CMDLINE_LINUX_DEFAULT="quiet isocpus=3"
GRUB_CMDLINE_LINUX=""

does that second grub_cmdline_linux="" wipe out the line before?


I read some of the doc on pinning but honestly I really got lost on how to actually get that done.
Is there a pinning for dummies file somewhere? (there was a few links to a doc by Rod but the link is dead)

Thanks again, rebooting.

BTW, what part of this am I looking to get better?

You can try this script to pin the IRQ:

 

Download and set as executable with chmod +x pinirq.txt before running:

sudo ./pinirq.txt [ethernet_device_name]

Where [ethernet_device_name] is something like eno1, eth0, enp2s0 etc

You can use 

ip a

To determine the realtime Ethernet device name by its IP address
 

sudo ./pinirq.txt eno1
Cores: 4
Old CPU Mask: f
Set device eno1 IRQ 24 CPU mask to 8

Looks like it did something, how can I tell if it worked?
M