Latency-CPU1 not working
20 Dec 2021 17:25 #229561
by rajsekhar
Latency-CPU1 not working was created by rajsekhar
Dear All,
I am struggling to reach a max jitter value below 30k ns for last couple of weeks.
I am using a dual core CPU and 41 mother board, 4 GB ram.
BIOS setting are attached in photo.
I have set isolcpu=1 and upadte-grub is run.
But by using "TOP" command when I notice the CPU usage, CPU1 is 0 i.e not in use. This is something really not expected neighther I could found the reason/solution.
Please help. As I am not a computer guy, it is beyond my expertise.
Thanks in advance.
I am struggling to reach a max jitter value below 30k ns for last couple of weeks.
I am using a dual core CPU and 41 mother board, 4 GB ram.
BIOS setting are attached in photo.
I have set isolcpu=1 and upadte-grub is run.
But by using "TOP" command when I notice the CPU usage, CPU1 is 0 i.e not in use. This is something really not expected neighther I could found the reason/solution.
Please help. As I am not a computer guy, it is beyond my expertise.
Thanks in advance.
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20 Dec 2021 17:27 #229562
by rajsekhar
Replied by rajsekhar on topic Latency-CPU1 not working
Other photos of BIOS and screenshots.
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20 Dec 2021 17:33 #229564
by rajsekhar
Replied by rajsekhar on topic Latency-CPU1 not working
Cpu usage screen shots
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20 Dec 2021 17:46 #229565
by tommylight
So it is expected.
IRQ stuff you have in GRUB do not do much on new-ish systems.
Anyway you look at it, 30K is a very good latency if it does not spike during use.
Replied by tommylight on topic Latency-CPU1 not working
Isolcpu = isolate cpu = do not use cpu
I have set isolcpu=1 and upadte-grub is run.
But by using "TOP" command when I notice the CPU usage, CPU1 is 0 i.e not in use. This is something really not expected neighther I could found the reason/solution.
So it is expected.
IRQ stuff you have in GRUB do not do much on new-ish systems.
Anyway you look at it, 30K is a very good latency if it does not spike during use.
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21 Dec 2021 01:32 #229593
by rajsekhar
Replied by rajsekhar on topic Latency-CPU1 not working
Well, Max jitter is spiking beyond 30k..upto 50~55k with 5 glxgears..how to control? any solution?
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21 Dec 2021 02:08 #229597
by tommylight
Replied by tommylight on topic Latency-CPU1 not working
Yes, stop chasing that, go make the machine move and enjoy watching it.
It is usable, it should work, might have limited velocity, everything else should be fine.
It is usable, it should work, might have limited velocity, everything else should be fine.
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21 Dec 2021 14:08 #229623
by rajsekhar
Replied by rajsekhar on topic Latency-CPU1 not working
Understand..ok
But is there any risk of missing step output?? That is the point of concern..I can adjust with the limited velocity for this case.
But is there any risk of missing step output?? That is the point of concern..I can adjust with the limited velocity for this case.
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21 Dec 2021 14:25 #229626
by tommylight
Replied by tommylight on topic Latency-CPU1 not working
If you get latency warnings when using LinuxCNC, set the base period in the ini file higher, test again.
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20 Mar 2022 13:41 #237797
by rajsekhar
Replied by rajsekhar on topic Latency-CPU1 not working
Ḥello..everyone..I take the opportunity to inform the final result of the latency war as follows:
- I finally ended with RT-Preempt kernel, RTAI does not support additional parallel ports which are available here in INDIA.
- Using video card RADEON HD 7300 1GB. this actually solved the issue.
- I finally not using any CPU isolation and also not using multitasking the PC either.
- Latency is under 25k ns mostly.
The following user(s) said Thank You: tommylight
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