# &app; Manual V&manrevision;

## Introduction

The &app; application enables you to monitor system processes and usage of system resources. You can also use &app; to modify the behavior of your system.

The &app; window contains two tabbed sections:

Process Listing

- Shows active processes, and how processes are related to each other. Provides detailed information about individual processes, and enables you to control active processes.

Resource Monitor

- Displays the current usage of the following system resources:

  - CPU (central processing unit) time

  - Memory and swap space

  - Disk space on each device

## Getting Started

### To Start &app;

You can start &app; in the following ways:

Applications menu

- Choose System Tools System Monitor.

Command line

- Execute the following command: `gnome-system-monitor`

### When You Start &app;

When you start &app;, the following window is displayed:

#### &app; Window

Shows System Monitor main window.

The &app; window contains the following elements:

Menubar

- The menus on the menubar contain all of the commands that you need to work with &app;.

Display area

- The display area contains the system monitor information. The display area contains the following tabbed sections:

  - Process Listing

    Contains a Search text box, a View drop-down list, a list of processes organized as a table, a More Info button, and an End Process button.

    Do not confuse the View drop-down list on the Process Listing tabbed section with the View menu in the menubar.

  - Resource Monitor

    Contains a CPU History graph, a Memory and Swap History graph, and a list of Devices organized as a table.

Statusbar

- The statusbar displays information about current &app; activity and contextual information about the menu items.

## Usage

### To Display the Process List

To display the process list, select the Process Listing tab. The Process Listing tab is displayed by default when you start &app;.

In the Process Listing tab, the processes are organized as a table. The rows of the table display information about the processes. The columns represent information fields for the processes, such as the name of the user who owns the process, the amount of memory currently being used by the process, and so on. From left to right, the Process Listing tab displays the following columns by default:

- Process Name

- User

- Memory

- X Server Memory

- Nice

- ID

For information about how to change the columns displayed in the process list, see gnome-system-monitor-prefs-proclist.

#### Parent Processes, Child Processes, and Threads

A parent process is a process that spawns another process. The spawned process is a child process of the original parent process. By default, &app; shows process dependencies. For information about how to change the default display behavior, see gnome-system-monitor-modify-processlist-viewdeps.

A thread is a portion of a process that can run independently of and concurrently with other portions of the process. By default, &app; does not show threads. For information about how to change the default display behavior, see gnome-system-monitor-modify-processlist-viewthreads.

#### Process Priority and Nice Values

Processes run in order of priority: high-priority processes run before low-priority processes. Child processes generally inherit their priority from their parent process.

The priority of a process is set by the nice value of the process, as follows:

- A nice value of 0 means that the process has normal priority.

- The higher the nice value, the lower the priority.

- The lower the nice value, the higher the priority.

For information about how to change the priority of a process, see gnome-system-monitor-change-priority.

### To Sort the Process List

To sort the process list, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. By default, the processes are listed by name, in alphabetical order. To list the processes in reverse alphabetical order, click on the Process Name column header.

3. Click on any column header to sort the processes by the information in that column, in alphabetical or numerical order.

4. Click again on the column header to sort the data in reverse alphabetical or reverse numerical order.

### To Modify the Contents of the Process List

You can modify the contents of the process list in several ways.

#### To Show All Processes

To show all processes in the process list, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. Click on the View drop-down list, then select All Processes.

#### To Show Only Processes Owned by the Current User

To show only the processes that are owned by the current user, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. Click on the View drop-down list, then select My Processes.

#### To Show Only Active Processes

To show only the active processes in the process list, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. Click on the View drop-down list, then select Active Processes.

#### To Show Process Dependencies

To show process dependencies in the process list, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. Choose View Process Dependencies.

If the Process Dependencies menu item is selected, the processes are listed as follows:

- Parent processes are indicated by a triangle symbol to the left of the process name. Click on the triangle symbol to show or hide the associated child processes.

- Child processes are indented, and listed with their parent process.

If the Process Dependencies menu item is not selected:

- Parent processes and child processes are not distinguishable.

- All processes are listed in alphabetical order.

#### To Show Threads

To show threads in the process list, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. Choose View Threads.

#### To Hide a Process

To hide a process, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. Select the process that you want to hide.

3. Choose Edit Hide Process.

   By default, a confirmation alert is displayed. For information about how to display or hide the confirmation alert, see gnome-system-monitor-prefs-proclist.

4. Click on the Hide Process button to confirm that you want to hide the process.

#### To Re-Display Hidden Processes

To re-display hidden processes in the process list, perform the following steps:

1. Choose Edit Hidden Processes. If no processes are currently hidden, an information alert is displayed. If any processes are currently hidden, the Manage Hidden Processes dialog is displayed.

2. Select the processes that you want to re-display in the process list.

3. Click on the Remove From List button. The processes are no longer hidden, and are displayed in the process list.

4. Click Close to close the Manage Hidden Processes dialog.

### To Find a Process

To find a process in the process list, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. Type the name of the process in the Search text box. Wildcards are not supported.

3. Press Return.

   If the process exists, &app; highlights the process name in the process list. Press Return repeatedly to highlight other occurrences of the process name in the process list.

   If the process does not exist, &app; displays an error dialog.

### To Show or Hide Additional Process Information

To show additional information about a process, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. Select the process in the process list.

3. Click on the More Info button.

&app; displays the following additional process information:

Process Info

- - Command

    The name of the command that started the process.

  - Status

    The current status of the process: sleeping or running.

  - Priority

    The priority of the process, and the associated nice value.

Memory Usage

- - Total

    The total amount of memory used by the process.

  - RSS

    The amount of RSS or physical memory used by the process.

  - Shared

    The amount of shared memory used by the process.

To hide the additional process information, click on the Less Info button.

You can also double-click on the process in the process list, to show or hide the additional process information.

### To Display Memory Maps for a Process

To display memory maps for a process, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. Select the process in the process list.

3. Choose View Memory Maps.

The Memory Maps dialog displays the information in tabular format. The name of the process is displayed above the memory-map table. From left to right, the Memory Maps dialog displays the following columns:

Filename

- The location of a shared library that is currently used by the process. If this field is blank, the memory information in this row describes memory that is owned by the process whose name is displayed above the memory-map table.

VM Start

- The address at which the memory segment begins.

VM End

- The address at which the memory segment ends.

VM Size

- The size of the memory segment.

Flags

- The following flags describe the different types of memory-segment access that the process can have:

  p

- The memory segment is private to the process, and is not accessible to other processes.

r

- The process has permission to read from the memory segment.

s

- The memory segment is shared with other processes.

w

- The process has permission to write into the memory segment.

x

- The process has permission to execute instructions that are contained within the memory segment.

VM offset

- The virtual memory offset of the memory segment.

Device

- The major and minor device numbers of the device on which the shared library filename is located.

Inode

- The inode on the device from which the shared library location is loaded into memory.

Click on any column header to sort the data by the information in that column, in alphabetical or numerical order. Click again on the column header to sort the data in reverse alphabetical or reverse numerical order.

Click Close to close the Memory Maps dialog.

### To Change the Priority of a Process

To change the priority of a process, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. Select the process for which you want to change the priority.

3. Choose Edit Change Priority. The Change Priority dialog is displayed.

4. Use the slider to set the nice value of the process.

   The nice value sets the priority of the process: the lower the nice value, the higher the priority.

   To specify a nice value lower than zero, non-root users must enter the root password.

5. Click on the Change Priority button.

### To End a Process

To end a process, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. Select the process that you want to end.

3. Choose Edit End Process, or click on the End Process button.

   By default, a confirmation alert is displayed. For information about how to display or hide the confirmation alert, see gnome-system-monitor-prefs-proclist.

4. Click on the End Process button to confirm that you want to end the process. &app; forces the process to finish normally.

This is the preferred way to stop a process.

### To Terminate a Process

To terminate a process, perform the following steps:

1. Select the Process Listing tab to display the process list.

2. Select the process that you want to terminate.

3. Choose Edit Kill Process.

   By default, a confirmation alert is displayed. For information about how to display or hide the confirmation alert, see gnome-system-monitor-prefs-proclist.

4. Click on the Kill Process button to confirm that you want to terminate the process. &app; forces the process to finish immediately.

You usually terminate a process only if you cannot end the process normally as described in gnome-system-monitor-end-process.

### To Monitor CPU Usage

To monitor CPU usage, select the Resource Monitor tab.

&app; displays the CPU usage history in graphical format. Underneath the graph, &app; also displays the current CPU usage, as a percentage.

### To Monitor Memory and Swap Usage

To monitor memory and swap usage, select the Resource Monitor tab.

&app; displays the memory usage history and the swap usage history in graphical format. Underneath the graph, &app; also displays the following numerical values:

- Used memory

- Total memory

- Used swap

- Total swap

### To Monitor Disk Space Usage

To monitor disk space usage, select the Resource Monitor tab.

&app; displays the disk space usage information in tabular format. From left to right, the Devices table displays the following columns:

Name

- The name of the device.

Directory

- The location of the device.

Type

- The type of the device.

Total

- The total amount of disk space available on the device.

Used

- The amount of disk space currently used on the device, expressed in bytes and as a percentage.

### To Customize the Resource Monitor Tabbed Section

You can customize the Resource Monitor tabbed section in the following ways:

- gnome-system-monitor-customize-background

- gnome-system-monitor-customize-grid

- gnome-system-monitor-customize-cpu

- gnome-system-monitor-customize-mem

#### To Change the Background Color of Graphs

To change the background color of the &app; graphs, perform the following steps:

1. Choose Edit Preferences. The Preferences dialog is displayed.

2. Select the Resource Monitor tab in the Preferences dialog.

3. Click on the Background color button. The Pick a color dialog is displayed.

4. Choose a color from the Palette, or use the color wheel or the spin boxes to customize the color.

5. Click OK to close the Pick a color dialog.

6. Click Close to close the Preferences dialog.

#### To Change the Grid Color of Graphs

To change the grid color of the &app; graphs, perform the following steps:

1. Choose Edit Preferences. The Preferences dialog is displayed.

2. Select the Resource Monitor tab in the Preferences dialog.

3. Click on the Grid color button. The Pick a color dialog is displayed.

4. Choose a color from the Palette, or use the color wheel or the spin boxes to customize the color.

5. Click OK to close the Pick a color dialog.

6. Click Close to close the Preferences dialog.

#### To Change the Line Color of the CPU Graph

To change the color of the line that represents CPU usage in the CPU History graph, perform the following steps:

1. Select the Resource Monitor tab in the System Monitor window, to display the graphs and table that provide information about the usage of system resources.

2. Click on the CPU color button. The Pick a color dialog is displayed.

3. Choose a color from the Palette, or use the color wheel or the spin boxes to customize the color.

4. Click OK to close the Pick a color dialog.

#### To Change the Line Colors of the Memory and Swap Graph

To change the color of the lines that represent memory and swap usage in the graph, perform the following steps:

1. Select the Resource Monitor tab in the System Monitor window, to display the graphs and table that provide information about the usage of system resources.

2. Click on the Used memory or Used swap button. The Pick a color dialog is displayed.

3. Choose a color from the Palette, or use the color wheel or the spin boxes to customize the color.

4. Click OK to close the Pick a color dialog.

## Preferences

To configure &app;, choose Edit Preferences. The Preferences dialog contains the following tabbed sections:

- gnome-system-monitor-prefs-proclist

- gnome-system-monitor-prefs-resmon

### Process Listing

Behavior

- - Update interval ... seconds

    Use this spin box to specify the interval at which you want to update the process list.

  - Show warning dialog when ending or killing processes

    Select this option to display a confirmation alert when you end a process or terminate a process.

  - Show warning dialog when hiding processes

    Select this option to display a confirmation alert when you hide a process.

Process Fields

- Use the following options to select which fields are displayed in the process list:

  - Process Name

    Select this option to display the name of the process. This column may also contain an icon to indicate the application that is associated with the process.

  - Arguments

    Select this option to display the name of the command, including arguments, that started the process.

  - User

    Select this option to display the name of the user who owns the process.

  - Status

    Select this option to display the current status of the process: sleeping or running.

  - Memory

    Select this option to display the amount of system memory that is currently being used by the process.

  - VM Size

    Select this option to display the amount of virtual memory that is allocated to the process.

  - Resident Memory

    Select this option to display the amount of physical memory that is allocated to the process.

  - Shared Memory

    Select this option to display the amount of shared memory that is allocated to the process. Shared memory is memory that can be accessed by another process.

  - RSS Memory

    Select this option to display the amount of physical memory, excluding swapped-out pages, that is used by the process.

  - X Server Memory

    Select this option to display the amount of X server memory that is used by the process.

  - % CPU

    Select this option to display the percentage of CPU time currently being used by the process.

  - Nice

    Select this option to display the nice value of the process. The nice value sets the priority of the process: the lower the nice value, the higher the priority.

  - ID

    Select this option to display the process identifier, also known as the pid. The pid is a number that uniquely identifies the process. You can use the pid to manipulate the process on the command line.

### Resource Monitor

Graphs

- - Update interval ... seconds

    Use this spin box to specify how often you want to update the &app; graphs.

  - Background color

    Use this button to customize the background color of the &app; graphs, as described in gnome-system-monitor-customize-background.

  - Grid color

    Use this button to customize the grid color of the &app; graphs, as described in gnome-system-monitor-customize-grid.

Devices

- - Update interval ... seconds

    Use this spin box to specify how often you want to update the Devices table.