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Linux/AM5728: Core isolation methods

Part Number: AM5728

Tool/software: Linux

Dear Champs,

My customer is trying to test core-isolation using shield as described in Linux-RT performance guide, but failed.

Could you please let me know if there is a other method to isolate each core?

How about cset described in below?

http://skebanga.blogspot.kr/2012/06/cset-shield-easily-configure-cpusets.html

root@am57xx-evm:~# cset shield --kthread=on --cpu 1

root@am57xx-evm:~# cset shield --exec cyclictest --  -l100000 -m -n -a0 -t1 -p99 -i200 -h400 -q

Thanks and Best Regards,

SI.

  • The software team have been notified. They will respond here.
  • There are two different core isolation methods that I know. One is the technique the customer is trying the other is isolated a core a boot time. Could the customer please describe why they think the cset shield techinque is not working for them?
  • They feels the isolation was not perfect when they used cset shield and they found there is not much difference in latency value with normal case. So, they questioned if there is other method to isolate core.

    Thanks and Best Regards,
    SI.
  • Hi,
    Yes there is another way to isolate the cores on the AM572x. This method isolates the core at kernel boot and is accomplished by passing a command line parameter from u-boot.

    setenv optargs isolcpus=1

    They can just boot from after setting the above parameter or they can perform a saveenv in uboot and the isolation will happen on the reboot too. If they this command line parameter then cat /proc/sched_debug should show a minimal amount of threads that are tied to the core of the part.

    How many threads are seeing with the cat /proc/sched_debug command after the cset approach?

    Regards,
    Schuyler