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

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15 Nov 2022 21:05 #256800 by tommylight
While you are at it, can you please add a way to find out the IP address and gateway address and ping the gateway say 50 or 100 times and report the times?
That would be helpful to point out some PC's having issues with new kernels and network cards causing loss of connection to controler boards.
So far Intel network cards are OK, some just need setting IRQ coalesing to 0, some work out of the box.
Realtek cards have something wrong in the kernel, and despite having good ping times tend to drop the link consistently.
Not sure how usefull will that be due to above reasons, but maybe there is a pattern somewhere.

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15 Nov 2022 22:04 #256803 by seuchato
At your service! I am currently looking into disc load. I will add this to the todo list. Is this important? If, I'll give it priority, say 3 :-). Rest will be in script development thread - soon.
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15 Nov 2022 22:23 #256809 by D.L.
seuchato, I think new version of LinuxCNC(2.8.x) shows worse latency results, no matter what type of disk is used.
In the near future i will test LinuxCNC version 2.7.14 with SSD and with 5 glxgears, this will show the real effect on disk type changes.

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16 Nov 2022 13:39 #256859 by D.L.
MB  GA-J1800N-D2H(BIOS F6)
RAM KVR13S9S8/4 4Gb
SSD SA400S37/240G
Debian Wheezy 3.2.0-6-rt-686-pae
LinuxCNC v. 2.7.14

kernel parameters: "isolcpus=0 lapic quiet"
 

kernel parameters: "isolcpus=1 lapic quiet"
 

With SSD the result is the same as 4 years ago.
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16 Nov 2022 16:01 #256867 by tommylight
Add
--show
At the end of latency-histogram command, there are spikes outside of visible area on both screenshots.
Those two colored columns at both sides of the plot in red and green or red and blue, those are spikes.
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28 Mar 2023 18:31 #267722 by tommylight


Acer Aspire 3 laptop, works perfectly with LinuxCNC, been on since last night trying to home a machine. :)
Mint19.3, LinuxCNC 2.8, kernel 4.9.
Removing power adapter does drop the link to Mesa, but works on bateries for nearly 3 hours without issues.
Beware that this model has issues with keyboards, this one does not work at all most of the time. Pity as it is very thin and lite with a nice full HD screen and a very cr@ppy 640x480 camera, good batery life.
Will add more info later.
Also got an Acer Switch 5 tablet PC, using a USB>LAN dongle can run machines very nicely for testing, but if screen blanks it does drop the link on wake up.
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06 Apr 2023 13:52 #268433 by royka
OrangePi-5 with rt-kernel, in another thread you could find how to build this kernel/image.
I did try to make it harder for that board but it improved the latency, perhaps the same kind effect as idle=poll.
 
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04 May 2023 10:26 - 04 May 2023 15:50 #270625 by royka
Old tv-box I had lying around, S912-2gb. It could be a bit tricky to install.
The emmc of this box is damaged, to be able to boot from sd I'd to write a different u-boot to the sd. This box froze every time while it was reading/writing from sd with the preempt_rt kernel and some cores isolated. Eventually with the boot partition and u-boot on sd and rootfs on usb it performs fine.

Perhaps it works even better when it's installed to the emmc. The servo thread stayed below 10uS until it did IO heavy tasks. ran out of ram.
 

After replacing Mate with xfce and lowering the resolution to prevent it from running out of ram the result is much better.
 
 
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10 May 2023 12:27 #271103 by routerman22
Dell optiplex 7050 mini I5-6500 + 8gb ram + 256gb ssd. I made some additional changes, you can read about it on my blog here .

youtube full hd video + 4x glxgears
Debian 12 

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10 May 2023 20:54 #271127 by royka
Optiplex 7040 mini i5-6500T + 2x4gb (DDR memory works faster in pairs)

extra boot archs: 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

Kernel compiled + config: mega.nz/folder/T9gCUZCQ#aQDlVgPDAMtaRgF_-Vzd5g

 


 
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