title: Why do I see high CPU usage for one process but the overall CPU idle percentage is high?
body: <p>This is a 8 core machine.
  The %Cpu(s)->id is 99.4 but one java process already occupies 82.7% cpu usage.</p>
  
  <p>The "top" output is as below:</p>
  
  <pre><code>top - 09:04:09 up 17:22,  1 user,  load average: 0.00, 0.00, 0.00
  Tasks: 142 total,   1 running,  74 sleeping,   0 stopped,   0 zombie
  %Cpu(s):  0.1 us,  0.1 sy,  0.0 ni, 99.4 id,  0.0 wa,  0.0 hi,  0.0 si,  0.3 st
  KiB Mem : 62876640 total,  9865752 free, 51971500 used,  1039388 buff/cache
  KiB Swap:        0 total,        0 free,        0 used. 10121552 avail Mem
  
    PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
   4859 root      20   0   50.1g  49.4g 144356 S  82.7 82.4  20:28.62 java
   3847 root      20   0    6452    792    716 S   0.3  0.0   0:09.50 rngd
      1 root      20   0   43724   5680   4196 S   0.0  0.0   0:02.30 systemd
      2 root      20   0       0      0      0 S   0.0  0.0   0:00.01 kthreadd
  </code></pre>