虽然htop更modern，但是top毕竟是自带。
# 查看指定程序
top -p`pidof <program>`
# 按H可以展示线程，可用于查看各线程CPU占用
top - 15:29:49 up 954 days, 23:27, 6 users, load average: 0.00, 0.06, 0.63
Threads: 16 total, 0 running, 16 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0.1 us, 0.0 sy, 0.0 ni, 99.8 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem : 24689460 total, 7071788 free, 181036 used, 17436636 buff/cache
KiB Swap: 0 total, 0 free, 0 used. 23842748 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
9867 bingbin+ 20 0 615688 32832 19904 S 4.3 0.1 0:34.90 feeder_handler
9864 bingbin+ 20 0 615688 32832 19904 S 0.3 0.1 0:00.50 SZL2ZhuBiSort
9854 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.33 feeder_handler
9855 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.01 feeder_handler
9856 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.40 WorkThread1
9857 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.00 WorkThread2
9858 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.00 WorkThread3
9859 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.00 WorkThread4
9860 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.17 IOManagerImpl
9861 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.21 HttpHandler
9862 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.23 FileWriter
9863 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.00 PubSortedThrd
9865 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.42 SZL2ZhuBiSort
9866 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.48 SZL2ZhuBiSort
9868 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.03 feeder_handler
9869 bingbin+ 20 0 615688 32832 19904 S 0.0 0.1 0:00.36 IOManagerImpl常用快捷键：
- e: 切换数值显示单位，m、g、t、p
- m：显示内存用量条
- M：按内存占用排序
- z：上色
- H：切换显示线程
- c: 切换显示完整命令行
- N：固定顺序，行不再跳来跳去