Figure 1-4. The gtop memory usage display
This window shows the percentage of memory used by different programs. Each section is colour-coded and labelled. The number in brackets after a program's name is the number of instances of that program running. If you have gnome-terminals or xterminals open, for example, you will see more than one instance of these and of bash, or your preferred shell, running. The default display shows the Resident Set Size (the amount of physical memory used by the program and the shared libraries that it needs, but not swapped-out data) for all processes. Other displays can be invoked from the View Menu and the Preferences box.
Several menu options can affect the display in the memory window. There is also a toolbar which is described in the Processes section of this document.
The File Menu provides the same options as the File Menu on the Processes Window. See there for the description.
The View Menu provides a choice of five options:
The Resident Set Size shows the total of what is in physical memory, both the program and any shared libraries associated with it. It does not show data about anything which has been swapped out to disk.
FIXME: Need a clear explanation of what Shared Size memory view means.
FIXME: Need a clear explanation of what Total Size memory view means.
FIXME: Need a clear explanation of what Virtual Size memory view means.
Swapped Size shows the sizes of what's in swap. When something is swapped out, it means that not all of the program is in physical memory. All or some of it has been moved from the memory to the hard drive, into the 'swap partition'. When the program requires it again, it will put it back into memory. The process of swapping between memory and disk can be slow, so programs which swap a lot can appear to progress in jerks rather than running smoothly.
The Settings Menu gives access to the Preferences dialogue.
The Windows Menu provides a choice of which of gtop's three displays to show: Processes, Memory Usage, or Filesystems.
The Help Menu gives access to the About dialogue box and gtop's credits.