Need to figure out where your CPU resources are going and if it's time to add more memory? Find out with KSysGuard.

KDE System Guard, or KSysGuard, is a program that offers you a look at how your system is running. Although many users may feel KSysGuard tells them a lot more than they want to know, a quick look at it can answer questions such as "Should I buy more RAM?"

You can start KSysGuard by entering ksysguard in a run box (Alt-F2), or you can find it listed in the K menu. On Kubuntu, it appears in the System sub-menu. Once started, KSysGuard displays four graphs. Figure 1 is an example of what should appear.

Figure 1. KSysGuard's Graph Display

With the System Load tab selected (the default), you see the graphs. Selecting the Process Table tab (Figure 2) gives you a detailed view of each running program. Across the bottom, you can a process count and some statistics on memory and swap usage. Mainly, though, the graphs are the things of interest to users.

Figure 2. The Process Table Tab Offers More Details

The first graph in Figure 1 shows CPU Load. It is a percentage graph that shows what percentage of the CPU is being used over time. Primarily of interest is the total percentage being used, but the information is displayed in three colors. Right-clicking on the graph and selecting Properties allows you to configure characteristics of this graph. Picking the Sensors tab shows you the meaning of the colors.

Figure 3. The Sensor tab displays what the colors in the CPU Load graph represent.

The majority of what is being shown in the Physical Memory graph is in blue, which represents time your application program is using. Orange, in contrast, is the time the Linux operating system is using. If, for example, you were performing a lot of disk writes, this percentage could go up. Yellow is labeled as nice, which essentially means time being used by a program that said it wasn't that important.

The next graph in Figure 1 is labeled Load Average. My graph varies between about 1.2 and 1.8, which tells me the average number of programs waiting to run. Typically, this number should be relatively small; less than one is common. I happened to be copying a CD at the time I looked at the graph, though, so there was a lot of system activity.

By looking at these first two graphs, you can get an idea of why your system might be slow. If the load average number is around one, for example, but the CPU load is near 100%, it means a program is running that is using all of the CPU resources. Thus, a faster CPU would improve performance. On the other hand, if the CPU load is low but the Load Average is higher--let's say two or more--then the bottleneck is likely to be a storage device, such as a disk drive.

The Physical Memory and Swap Memory graphs need to be looked at together. Physical Memory means the RAM in your system. Swap Memory is space allocated on your hard disk that is used to save program code and data not currently needed in RAM. Swap is used only when your system runs out of physical memory, because it is much slower.

If physical memory is full and swap is being used, you may benefit from adding more RAM to your system. In fact, for most work, adding RAM is the cheapest and easiest way to increase system performance.

The Physical Memory graph displays information in three colors, much like the CPU Load graph. Right-clicking on the graph and selecting Properties brings up the details. Click on Sensors to see the meaning of each color. Application Memory (blue) is the space being used by running programs. Cached Memory and Buffered Memory are dynamic pools used to decrease the number of disk accesses that must be done. In a healthy system, most of the physical memory is used up by the total of these three items because that is more efficient. The real indication that more RAM would be beneficial for your system is when most of the physical memory is being used as application memory.

Figure 4. The Sensor tab displays what the colors in the Physical Memory graph represent.

This is the basic introduction to what KDE System Guard can tell you about your computer. For the more advanced user, the Process Table tab allows you to see what each program is doing. For the geeks out there, it is a clean way to display the same type of information that you get from running the top command.