how to remove kworker process on certain cpu core

Question

I have a process (testprogram) bind to core 50, and i dont want any context_switch.

1. /etc/default/grub: add with "isolcpus=50 nohz_full=50 rcu_nocbs=50"
2. ps -eLo psr,comm | grep '50'

0 watchdog/50 50 migration/50 50 ksoftirqd/50 50 kworker/50:0 50 kworker/50:0H 0 rcuob/50 11 rcuos/50 50 kworker/50:1 50 testProject

3. "sudo perf record -e sched:sched_switch -T -p PID" will record contex_switch, and i found kworker always take over the core50;

----how can i shut down kworker on core50;

-- i tried /sys/devices/virtual/workqueue/cpumask, but not work