A nice value doesn't work. It does not affect CPU utilization

Issue

• Set nice 19 to process A and -19 to process B, respectively.
• It is expected that process B will tend to be scheduled in preference to process A since process A is nicer than process B.
• However, CPU utilization of these processes does not differ much.

top - 14:08:04 up 11 days,  3:05,  1 user,  load average: 7.69, 3.94, 1.75
  PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND
11260 root      39  19 2343336 425236 127036 S 42.3  6.1 184:16.77 <process A>
25504 root       1 -19  107956    360    284 R 41.0  0.0   0:25.06 <process B>
                ^^ ^^^                         ^^^^