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HMüll.4
Senior
March 25, 2025
Solved

isolcpus kernel parameter is ignored - make use of one STM32MP257 core only?

  • March 25, 2025
  • 1 reply
  • 666 views

Hi,

I'm trying to run the whole ST-Linux-stuff on one core only to have the other one available for a time-consuming application. However, it seems the kernel-parameter isolcpus is not used, dmesg gives an output

[ 0.000000] Kernel command line: root=PARTUUID=e91c4e10-16e6-4c0e-bd0e-77becf4a3582 rootwait rw earlycon console=ttySTM0,115200 isolcpus=0
[ 0.000000] Unknown kernel command line parameters "isolcpus=0", will be passed to user space.
[ 2.309368] isolcpus=0

The message is correct, also with this parameter set, the processes are spread over all cores.

What could be the problem here? 

Thanks!

 

Best answer by Erwan SZYMANSKI

Hello @HMüll.4 ,
I find it strange that you have this warning on your second line. I have it too using the same command line parameter as you have. However, using 1 as parameter, the warning is not here anymore and it seems to have the expected result.
Can you please make a try with isolcpus=1 instead of 0 ?

Kind regards,
Erwan.

1 reply

Erwan SZYMANSKI
Erwan SZYMANSKIBest answer
Technical Moderator
March 28, 2025

Hello @HMüll.4 ,
I find it strange that you have this warning on your second line. I have it too using the same command line parameter as you have. However, using 1 as parameter, the warning is not here anymore and it seems to have the expected result.
Can you please make a try with isolcpus=1 instead of 0 ?

Kind regards,
Erwan.

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