Chapter 7 Improving Performance

This chapter describes how to improve the performance of the GNOME Desktop.

• Introduction to Improving Performance

• Reducing CPU Usage

• Reducing X Window System Network Traffic

• Reducing Color Usage and Improving Display Quality

Introduction to Improving Performance

This chapter lists several preferences whose settings you can change to improve the performance of the desktop environment. You can use the gconftool-2 command to set values for preferences for users. The example commands in this chapter show how to set values in the user configuration source.

You can also use the --direct and --config-source options to set mandatory values or default values for preferences. You can also use the gconftool-2 command in a script to set the values of many preferences. For more information on the gconftool-2 command and the options that are available with the command, see Chapter 1, Using GConf.

You can also use the --direct and --config-source options to set mandatory values or default values for preferences. You can also use the gconftool-2 command in a script to set the values of many preferences. For more information on the gconftool-2 command and the options that are available with the command, see Using GConf.

Reducing CPU Usage

This section describes preferences that you can set to reduce CPU usage by the desktop environment.

To Use Themes Which Require Less CPU Resources

Some window frame themes load image files to draw the window frame. Other themes use simpler techniques to draw the window frame.

The default theme is Crux. Crux loads image files, and can be slow on systems with limited CPU resources. To reduce CPU usage, use one of the following window frame themes:

• Atlanta

• Esco

The following window frame themes also use less CPU resources than Crux:

• AgingGorilla

• Bright

• Metabox

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Note –

Metabox does not work well with inverse desktop themes such as HighContrastInverse. Use Atlanta with inverse desktop themes.

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To change the window frame theme, run the following command:

# gconftool-2 --type string --set /apps/metacity/general/theme theme-name

For example, to use Atlanta, run the following command:

# gconftool-2 --type string --set /apps/metacity/general/theme Atlanta

Alternatively, users can choose Applications -> Desktop Preferences -> Theme, then select the appropriate theme.

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Tip –

You can use the Metacity Theme Viewer to measure the performance of a window frame theme, and to preview the theme. To start Metacity Theme Viewer, use the following command:

# metacity-theme-viewer theme-name

For example, to measure the performance of Atlanta and preview Atlanta, run the following command:

# metacity-theme-viewer Atlanta

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To Reduce CPU Usage by Turning Off Display of Icons in Menus

Some items in menus display an icon beside the item. To turn off this feature, run the following command:

# gconftool-2 --type bool --set /desktop/gnome/interface/menus_have_icons false

Alternatively, users can choose Applications -> Desktop Preferences -> Menus & Toolbars, then deselect the Show icons in menus option.

To Reduce CPU Usage by Turning On Wireframe Mode

The Metacity window manager has a wireframe mode for when you move and resize windows. When wireframe mode is turned on, only the outline of windows is displayed when you move and resize windows. The contents of the window do not need to be updated during the move or resize. The contents of the window are displayed when the move or resize is complete.

To turn on wireframe mode, run the following command:

# gconftool-2 --type bool --set /apps/metacity/sun_extensions/wireframe_move_resize true

To Reduce CPU Usage by Turning Off the Splash Screen

By default, when users log in to the desktop environment, a splash screen is displayed. Icons are displayed on the splash screen while the user logs in. You can turn off the splash screen to reduce CPU usage during login.

To turn off the splash screen, run the following command:

# gconftool-2 --type bool --set /apps/gnome-session/options/show_splash_screen false

Alternatively, users can choose Applications -> Desktop Preferences -> Advanced -> Sessions, then deselect the Show splash screen on login option.

To Reduce CPU Usage by Turning Off Panel Animation

When users show or hide panels, the panels can show or hide in an animated style. To turn off panel animation, run the following command:

# gconftool-2 --type bool --set /apps/panel/global/enable_animations false

Alternatively, users can choose Applications -> Desktop Preferences -> Advanced -> Panel, then deselect the Animation option.

Improving File Manager Performance

The Nautilus file manager includes some features that you can modify to improve performance.

To Modify Performance Preferences

The file manager includes performance-related preferences. Each performance preference can take one of three values. The values are described in the following table:

Value	Description
always	Performs the action for both local files, and files on other file systems.
local_only	Performs the action for local files only. When you set a performance preference to local_only, the CPU usage is reduced.
never	Never performs the action. When you set a performance preference to never, the CPU usage and the network traffic are reduced.

The following table describes the performance preferences for the file manager. For the fastest performance, set the value of the preferences to never.

Preference	Description
show_icon_text	Specifies when to preview the content of text files in the icon that represents the file. To never preview the content of text files, run the following command:   # gconftool-2 --type string --set /apps/nautilus/preferences/ show_icon_text never Alternatively, users can perform the following steps:  Choose Edit -> Preferences from a file manager window, then choose Performance. Select an option for the Show Text in Icons preference.
show_directory_item_counts	Specifies when to show the number of items in folders. To never show the number of items in folders, run the following command:  # gconftool-2 --type string --set /apps/nautilus/preferences/ show_directory_item_counts never Alternatively, users can perform the following steps:  Choose Edit -> Preferences from a file manager window, then choose Performance. Select an option for the Show Number of Items in Folders preference.
show_image_thumbnails	Specifies when to show thumbnails of image files. To never show thumbnails, run the following command:  # gconftool-2 --type string --set /apps/nautilus/preferences/ show_image_thumbnails never Alternatively, users can perform the following steps:  Choose Edit -> Preferences from a file manager window, then choose Performance. Select an option for the Show Thumbnails for Image Files preference.
preview_sound	Specifies when to preview the content of sound files. To never preview the content of sound files, run the following command:  # gconftool-2 --type string --set /apps/nautilus/preferences/preview_sound never Alternatively, users can perform the following steps:  Choose Edit -> Preferences from a file manager window, then choose Performance. Select an option for the Preview Sound Files preference.

To Turn Off the Side Pane, Toolbar, and Location Bar

The file manager includes preferences that enable you to turn off the side pane and the toolbar. To improve file manager performance, turn off the side pane and the toolbar.

To turn off the side pane, run the following command:

# gconftool-2 --type bool --set /apps/nautilus/preferences/start_with_sidebar false

Alternatively, users can choose Edit -> Preferences from a file manager window, then choose Windows, and then deselect the Display side pane option. The next time that users open a file manager window, the window does not display a side pane.

To turn off the toolbar, run the following command:

# gconftool-2 --type bool --set /apps/nautilus/preferences/start_with_toolbar false

Alternatively, users can choose Edit -> Preferences from a file manager window, then choose Windows, and then deselect the Display toolbar option. The next time that users open a file manager window, the window does not display a toolbar.

You can also turn off the location bar. Users can use the Ctrl + L keyboard shortcut to display a location bar when required.

To turn off the location bar, run the following command:

# gconftool-2 --type bool --set /apps/nautilus/preferences/start_with_location_bar false

Alternatively, users can choose Edit -> Preferences from a file manager window, then choose Windows, and then deselect the Display location bar option. The next time that users open a file manager window, the window does not display a location bar.

To Turn Off the Desktop

The file manager contains a preference that enables users to use Nautilus to manage the desktop. Users can disable the desktop to improve performance. However, if users disable the desktop, users cannot do the following:

• Use the Desktop menu.

• Use the file manager to change the pattern or color of the desktop background.

• Use the Home object and the Trash object. The Home object and the Trash object are not displayed on the desktop.

To disable the desktop, run the following command:

# gconftool-2 --type bool --set /apps/nautilus/preferences/show_desktop false

Alternatively, users can choose Edit -> Preferences from a file manager window. Users can then choose Desktop & Trash, and then deselect the Use Nautilus to draw the desktop option.

To Use the mediaLib Libraries

The mediaLib™ libraries are a collection of functions that accelerate common multimedia operations. The desktop environment uses the mediaLib libraries if the libraries are installed on the system. The performance of the desktop environment, especially Nautilus, improves significantly when the mediaLib libraries are installed. The desktop environment requires mediaLib version 2.0 or higher.

For information on how to obtain and install the mediaLib libraries, see the mediaLib website at http://www.sun.com/processors/vis/mlib.html.

Reducing X Window System Network Traffic

This section describes preferences that you can set to reduce X Window System network traffic on the desktop environment.

To Use Themes Which Create Less Network Traffic

Remote display protocols do not transfer every pixel in a block of pixels if all pixels in the block are the same color.

To reduce X Window System network traffic, use a window frame theme that uses solid colors. That is, use one of the following window frame themes:

• Atlanta

• Esco

For information on how to change the theme, see To Use Themes Which Require Less CPU Resources.

To Reduce Network Traffic by Turning Off Display of Icons in Menus

Some items in menus display an icon beside the item. If the icon is located on another file system, this feature can increase X Window System network traffic. This feature can also increase X Window System network traffic if the panels are displayed on a remote host. For example, if a Sun Ray server runs the panels and displays the panels on a Sun Ray client.

For information on how to turn off this feature, see To Reduce CPU Usage by Turning Off Display of Icons in Menus.

To Reduce Network Traffic by Turning On Wireframe Mode

If the application that displays the window is running on a remote host, wireframe mode reduces X Window System network traffic.

For more information on wireframe mode, see To Reduce CPU Usage by Turning On Wireframe Mode.

Reducing Color Usage and Improving Display Quality

Many modern computer systems support 24-bit color, that is, 16,777,216 colors. However, many users still use systems that support 8-bit color, that is, 256 colors.

The desktop environment uses the websafe color palette. This palette is a general-purpose palette of 216 colors, which is designed to optimize the use of color on systems that support 8-bit color. However, some visual components of the desktop environment are designed for systems that support 24-bit color.

The following display problems might occur on systems that support 8-bit color:

• Windows, icons, and background images might appear grainy. Many themes, background images, and icons use colors that are not in the websafe color palette. The colors that are not in the palette are replaced with the nearest equivalent or a dithered approximation. This use of replacement colors causes the grainy appearance.

• Applications that do not use the websafe color palette have less colors available. Color errors might occur. Some colors might not appear in the user interface of the application. Some applications might crash if the application cannot allocate colors.

• Color flashing might occur when users switch between applications that use the websafe color palette, and applications that do not use this palette. The applications that do not use the websafe color palette might use a custom colormap. When the custom colormap is used, other visual components might lose colors, then become unviewable.

The following sections describe how to optimize the appearance of the desktop environment for systems that support 8-bit color.

To Use Themes That Use the Websafe Color Palette

Some window frame themes use colors that are in the websafe color palette. Bright and Esco use colors from the websafe color palette. Bright and Esco do not have the grainy appearance of other themes on 8-bit color displays. Use Bright or Esco for the best color display on 8-bit visual modes.

For information on how to change the theme, see To Use Themes Which Require Less CPU Resources.

To Reduce Color Usage by Turning Off Display of Icons in Menus

Some items in menus display an icon beside the item. If the icon contains colors that are not in the websafe color palette, this feature can increase the number of colors used.

For information on how to turn off this feature, see To Reduce CPU Usage by Turning Off Display of Icons in Menus.

To Reduce Color Usage by Turning Off the Splash Screen

You can turn off the splash screen to make more colors available for the desktop environment and for applications.

For information on how to turn off the splash screen, see To Reduce CPU Usage by Turning Off the Splash Screen.

To Reduce Color Usage by Using a Solid Color for the Desktop Background

Use a solid color for the desktop background. Use of a solid color reduces the number of colors used by the desktop environment.

To set a solid color for the desktop background, run the following commands:

# gconftool-2 --type string --set /desktop/gnome/background/picture_options none

# gconftool-2 --type string --set /desktop/gnome/background/color_shading_type solid

# gconftool-2 --type string --set /desktop/gnome/background/primary_color \#hexadecimal-color

Alternatively, users can choose Applications -> Desktop Preferences -> Background, then choose a solid color for the desktop background.