Trace: • htop

htop

htop is an alternative display for top, showing system processes.

By default, htop will order the processes by PID.

FreeBSD

echo linproc /compat/linux/proc linprocfs rw 0 0 >> /etc/fstab
mkdir -p /usr/compat/linux/proc
ln -s /usr/compat /compat
mount linproc

Examples

Show processes being run by user mysql: 

htop -u mysql

Display threads for user apache, sorted by how long they have been running: 

htop -u apache --sort-key TIME

See how much memory apache threads are really using, highest values first: 

htop -u apache --sort-key M_RESIDENT

Watching the system to see what programs are using the most memory, the highest percentage of CPU, the highest percentage of memory, and then running the longest time: 

htop -u apache --sort-key M_RESIDENT
htop -u apache --sort-key PERCENT_CPU
htop -u apache --sort-key PERCENT_MEM
htop -u apache --sort-key TIME

Display Values

The default values displayed are:

  • PID
  • USER
  • PRIORITY
  • NICE
  • M_SIZE
  • M_RESIDENT
  • M_SHARE
  • STATE
  • PERCENT_CPU
  • PERCENT_MEM
  • TIME
  • Command

Gotchas

htop's argument for sorting by keys is not consistent across versions, despite what the –help output may say. To sort by a key, use –sort-key <value>, which will work everywhere.