Which kernel version is best for real time?
- langdons
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09 May 2025 13:29 #328067
by langdons
Replied by langdons on topic Which kernel version is best for real time?
Don't mess with BIOS settings unless you really know what you are doing.
Default values are usually the default for a reason.
(Sometimes the reason is stupid, but ususally not)
Setting the cooling profile to "performance" or "active" is always a good idea though.
Default values are usually the default for a reason.
(Sometimes the reason is stupid, but ususally not)
Setting the cooling profile to "performance" or "active" is always a good idea though.
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- unknown
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09 May 2025 17:50 #328090
by unknown
Replied by unknown on topic Which kernel version is best for real time?
Not quite true, disabling hyper threading is well worth it, as are a number of other generic options that have been discussed.
As for the kernel config, the most important settings are the preempt_rt ones, infact one of the easiest ways is to base the config for the new kernel on the running one.
If you really feel the issue is with the GPU I don't think a different kernel will fix much.
As for the kernel config, the most important settings are the preempt_rt ones, infact one of the easiest ways is to base the config for the new kernel on the running one.
If you really feel the issue is with the GPU I don't think a different kernel will fix much.
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- DarkPhoinix
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09 May 2025 19:19 #328098
by DarkPhoinix
Replied by DarkPhoinix on topic Which kernel version is best for real time?
youtube.com/shorts/mWCeSrF2TUM
I did a new test 100 windows of glxgears and CPU stresstest active the PC is no longer responsive even the linuxcnc window but the servo continues to go and finishes the job. I don't understand why YouTube goes into error! I must say that today the drivers arrived and the new servos do not make a minimum of noise but I have to check them in the car better.
I did a new test 100 windows of glxgears and CPU stresstest active the PC is no longer responsive even the linuxcnc window but the servo continues to go and finishes the job. I don't understand why YouTube goes into error! I must say that today the drivers arrived and the new servos do not make a minimum of noise but I have to check them in the car better.
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09 May 2025 21:00 #328106
by unknown
Replied by unknown on topic Which kernel version is best for real time?
Yeah I think even anon realtime kernel running a text editor with 100 glx windows open would become unresponsive. Honestly I'm of the opinion that is an unrealistic and silly test, that doesn't prove anything. You're testing for a situation that no sensible person would subject a computer to whilst running gcode.
Obviously you are expecting unrealistic things, and any further interaction is at this point a worthless endeavour on my part.
Obviously you are expecting unrealistic things, and any further interaction is at this point a worthless endeavour on my part.
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09 May 2025 23:50 #328111
by langdons
Replied by langdons on topic Which kernel version is best for real time?
Okay, disable hypethreading and turbo.
But don't mess with too much stuff.
"and any further interaction is at this point a worthless endeavour on my part."
Whoa!
Don't just write off people because they did one dumb thing!
But don't mess with too much stuff.
"and any further interaction is at this point a worthless endeavour on my part."
Whoa!
Don't just write off people because they did one dumb thing!
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09 May 2025 23:57 #328112
by langdons
Replied by langdons on topic Which kernel version is best for real time?
If your CNC setup works, then don't worry and just move on.
If you are paranoid, just set your max jitter to some really high value in your config.
Don't worry about stuff unless you need to.
If you are paranoid, just set your max jitter to some really high value in your config.
Don't worry about stuff unless you need to.
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- DarkPhoinix
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10 May 2025 16:59 #328162
by DarkPhoinix
do you mean this SERVO_PERIOD = 1000000 ?
I set it to 35000000. in the video with glxgear it is again at 1000000.
Replied by DarkPhoinix on topic Which kernel version is best for real time?
I did it and the situation gets worse! if I only move the linucnc window the steppers make absurd noises and change the speed of movement, they are not yet on the machine they are free.. I don't dare to think what they could do at work!If your CNC setup works, then don't worry and just move on.
If you are paranoid, just set your max jitter to some really high value in your config.
Don't worry about stuff unless you need to.
do you mean this SERVO_PERIOD = 1000000 ?
I set it to 35000000. in the video with glxgear it is again at 1000000.
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- tommylight
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10 May 2025 19:15 #328171
by tommylight
Replied by tommylight on topic Which kernel version is best for real time?
Do you get latency warnings when you run LinuxCNC?
Are you still using the same PC discussed here on several topics?
Why do you keep doing the same things and expect different results? Stressing the system beyond it's limits will always fail.
Change the graphic card, get a used one for AMD, or get a used PC.
You had good latency at one point in time, so what happened?
LinuxCNC, one youtube video, no whatever stress test you run, nothing, if that works OK, move on to making chips.
Are you still using the same PC discussed here on several topics?
Why do you keep doing the same things and expect different results? Stressing the system beyond it's limits will always fail.
Change the graphic card, get a used one for AMD, or get a used PC.
You had good latency at one point in time, so what happened?
LinuxCNC, one youtube video, no whatever stress test you run, nothing, if that works OK, move on to making chips.
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10 May 2025 19:42 #328175
by PCW
Replied by PCW on topic Which kernel version is best for real time?
Do you have a Ethernet connected motion device?
If so, the latency test is relatively useless for determining the actual
LinuxCNC latency.
A simple ping test is much more informative:
sudo chrt 99 ping -i .001 -q -c 60000 [Device_IP]
(will run 1 minute and print out timing statistics)
Where device _IP is the IP address of your Ethernet motion control interface.
If so, the latency test is relatively useless for determining the actual
LinuxCNC latency.
A simple ping test is much more informative:
sudo chrt 99 ping -i .001 -q -c 60000 [Device_IP]
(will run 1 minute and print out timing statistics)
Where device _IP is the IP address of your Ethernet motion control interface.
The following user(s) said Thank You: rodw
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