Results of latency test, list of computers tested for use with LinuxCNC

Hi all
Got all the data given in this thread now entered in a libre office table, see here .
Compiling this table helped me also to get an overview of what the script needs urgently. So hold on
Greez
chris

royka wrote:

That's pretty high indeed, did you try to disable as many as possible energy saving settings in the bios? Adding kernel parameters?

Perhaps there is a bad ram chip, you could try to remove 2 of them, 32gb is a lot for LinuxCNC, 4gb is enough most of the times. To keep dual channel, you probably need to have one in slot 1 and 3.

The kernel parameters that worked for my machine and you could try:
isolcpus=3 intel_pstate=disable processor.max_cstate=0 idle=poll cpufreq.default_governor=performance i915.enable_dc=0 ahci.mobile_lpm_policy=1 irqaffinity=0 nomodeset quiet

Hello, I have tested these kernel parameters, and I have managed to lower the latency to a stable 12k, but I have the problem that the screen resolution remains at 1028x768 instead of 1920x1080. I have removed the "nomodeset" and the resolution is set to 1920x1080 but the latency skyrockets.

Dell optiplex 7050 micro  (SFF?) I5-6500 + ssd + 1x8gb ram (2 ram stick would be higher performance)
Old pic:
forum.linuxcnc.org/18-computer/39371-res...cnc?start=330#271103

added these gub parameters:
forum.linuxcnc.org/18-computer/39371-res...cnc?start=330#271127

+ this IRQ schipt mod (had to manually install irqbalancer) : forum.linuxcnc.org/38-general-linuxcnc-q...ead-and-irq-affinity

= giant improvement :
8khz servo loop + 1 yt + 4x glx running @400-500fps 

New here and thought I would share a test from an older gaming pc I plan to use after getting some good results with it. This test was done from the bootable usb iso. Took lots of bios fiddling to get it this low.

pc specs:

• cpu: amd ryzen 5 3600x
• mobo: asrock b450 pro4
• ram: 16gb ddr4
• gpu: amd rx570
• some random brand pcie wifi card

https://imgur.com/a/71leQnJ

Looks good, great for software stepgen, you going to go with Mesa or Parallel Port setup ?

If you are going with Mesa there should be no need to isolate a cpu and you'll only need the servo thread,no base thread required.

If not make sure to search the forums regarding PCIe Parallel Port cards, there's a lot of info there and no need to start a new thread.

spicybagel wrote:

New here and thought I would share a test from an older gaming pc I plan to use after getting some good results with it. This test was done from the bootable usb iso. Took lots of bios fiddling to get it this low.

pc specs:

• cpu: amd ryzen 5 3600x
• mobo: asrock b450 pro4
• ram: 16gb ddr4
• gpu: amd rx570
• some random brand pcie wifi card
  
  

Thx for sharing this!
Did you move and/or resize the glxgears / browser window while runing the test?
greeez
chris

I picked up a mesa 7i96s after reading about that which is nice.

In the overclocking section there was an option to reduce it to either 2 or 4 cores and I only tested with 2. The setting that actually gave the most improvement from my testing was setting a custom core pstate frequency and changing the cpu frequency/voltage from auto to a set value. There were a bunch of other random suspicious power management setting I turned off and it wasn't a very scientific process sadly lol.

I did move the gears/browser around and let it run for a couple hours.
 

spicybagel
Thx a ton! Also for the hints on

• overclocking section
• custom core pstate frequency
• cpu frequency/voltage

Have to get more knowledge on these, too.
greez
chris

drive.google.com/drive/folders/1Wh2qURfV...81yiwalk?usp=sharing

Feel free to look through my bios settings, I took pictures of most settings for my own references. If you google the asrock b450 pro4 manual it explain what each setting does I think.