MeeGo 1.2 Harmattan Developer Documentation Develop for the Nokia N9

Using htop


The htop tool is a text-only, interactive process viewer. It is similar to the top tool, but with additional features:

  • The process list is scrollable.
  • The information on screen is configurable.
  • You can use the touch display or keyboard to control screen items.
  • Strace can be attached to a process with a single key press.
  • The htop tool can show threads in addition to processes.
  • TIME+ column value can be checked to find out process wake-ups (does the value increase).

The htop (or top) tool is mainly useful for checking whether memory usage changes. For accurate information on how much memory programs actually consume, use sp-memusage.

Packages

source: htop

binary: htop

Installing htop on the Harmattan device

Install htop through the developer mode applet.

Prerequisite: Developer mode must be enabled.

  1. Select Settings > Security > Developer mode.
  2. Install the Performance bundle package by clicking Install.
  3. You get a notification screen that lists all the applications to be installed in the bundle package. To install, click OK.
  4. A dependency notice appears. Click Accept.

For more information on developer mode and installable tools, see Activating developer mode.

Using the tool

You can run htop either in the terminal window of your host workstation or in the terminal tool available on the Harmattan device.

To use htop on your Harmattan device:

  • Launch the application from the command line on the device. However, note that the touch display of the device does not currently support all the features of the tool, such as changing the sorting order of the generated output.

Note: For a comprehensive list of the available commands, see the manual reference pages for this tool.

The following sections give usage examples for the htop tool.

Monitoring the processes

To see the running processes, enter the following command:

 htop

To show only processes owned by the root, enter the following command:

 htop -u root

To show processes sorted by CPU usage (call htop --sort-key help to see all sort keys), enter the following command:

 htop --sort-key PERCENT_CPU

The following output is displayed:


  CPU[########***********      58.8%]     Tasks: 198 total, 1 running
  Mem[|||||||||||||||##****236/479MB]     Load average: 0.00 0.00 0.00 
  Swp[||||||                87/456MB]     Uptime: 24 days, 01:51:32

  PID USER     PRI  NI  VIRT   RES   SHR S CPU% MEM%   TIME+  Command           
23852 root      20   0  2608  1044   828 R 23.0  0.2  0:00.15 htop --sort-key PE
    1 root      20   0  3016  1416   876 S  0.0  0.3  0:02.71 /sbin/init
  559 root      20   0  1912   484   396 S  0.0  0.1  0:06.46 udevd --daemon
  762 root      15  -5  1948   560   524 S  0.0  0.1  0:00.01 /usr/sbin/cellmo-w
 1006 root      RT  -5  1668  1608  1344 S  0.0  0.3  1:53.28 /sbin/dsme -p /usr
 1084 root      20   0  2860   556   512 S  0.0  0.1  0:00.27 /sbin/klogd -n
 1091 messageb  15  -5  4620  2660   880 S  0.0  0.5  0:18.71 /usr/bin/dbus-daem
 1101 root      -2  -5  6704  1352  1140 S  0.0  0.3  1:02.73 /sbin/dsme-server
 1105 root      -2  -1  6704  1352  1140 S  0.0  0.3  0:00.01 /sbin/dsme-server
 1113 root      20   0  1768   636   580 S  0.0  0.1  0:10.75 /sbin/syslogd -n
 1127 root      20   0  2076   924   736 S  0.0  0.2  0:04.83 -sh

If you are using the tool in the terminal window of your host workstation, you can change the sorting order by clicking the column headers.

Exiting the tool

To exit the tool, press 'q' or close the command-line terminal.

Further information

For more information on the tool, see the following link: