Java Desktop System Release 3 Administration Guide

Chapter 9 Improving Performance

This chapter describes how to improve the performance of the Java Desktop System.

Introduction to Improving Performance

This chapter lists several preferences whose settings you can change to improve the performance of the Java Desktop System. 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 about the gconftool-2 command and the options that are available with the command, see Chapter 1, Using GConf.

Reducing CPU Usage

This section describes preferences that you can set to reduce CPU usage by the Java Desktop System.

To Use Control Theme Options Which Require Less CPU Resources

Some control theme options can be slow on systems with limited CPU resources. To reduce CPU usage, use one of the following control options:

Crux
Mist
Simple

To change the control theme option, execute the following command:

# gconftool-2 --type string --set /desktop/gnome/interface/gtk_theme option-name

For example, to use Simple, execute the following command:

# gconftool-2 --type string --set /desktop/gnome/interface/gtk_theme Simple

Alternatively, users can use the Theme preference tool to select the appropriate option.

To Use Window Frame Theme Options Which Require Less CPU Resources

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

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

Atlanta
Esco
Mist
Simple

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

AgingGorilla
Bright
Metabox

Note –

Metabox does not work well with inverse controls options such as HighContrastInverse. Use Atlanta with inverse controls options.

To change the window frame theme option, execute the following command:

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

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

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

Alternatively, users can use the Theme preference tool to select the appropriate option.

Tip –

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

# metacity-theme-viewer option-name

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

# metacity-theme-viewer Atlanta

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, execute the following command:

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

Alternatively, users can use the Menus & Toolbars preference tool to deselect the Show icons in menus option.

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, execute the following command:

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

Alternatively, users can use the Sessions preference tool to 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, execute the following command:

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

Alternatively, users can use the Panel preference tool to deselect the Drawer and panel 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, execute 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 Preview. 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, execute 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 Preview. Select an option for the Count number of items preference.
`show_image_thumbnails`	Specifies when to show thumbnails of image files. To never show thumbnails, execute 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 Preview. Select an option for the Show thumbnails preference.
`preview_sound`	Specifies when to preview the content of sound files. To never preview the content of sound files, execute 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 Preview. 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, execute the following command:

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

To turn off the toolbar, execute the following command:

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

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, execute the following command:

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

To Turn Off the Desktop Background

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

Use the Desktop Background menu.
Use the file manager to change the pattern or color of the desktop background.
Use desktop background objects, such as Trash. The desktop background objects are not displayed on the desktop background.

To disable the desktop background, execute the following command:

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

To Reduce CPU Usage by Enabling Reduced Resources Mode

The Metacity window manager has a reduced resources mode which renders windows as wireframes when you move and resize windows. When reduced resources mode is enabled, 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. When reduced resources mode is enabled, windows are not animated when you move and resize the windows.

To enable reduced resources mode, execute the following command:

# gconftool-2 --type bool --set /apps/metacity/general/reduced_resources true

Note –

On Linux systems, if the /desktop/gnome/interface/accessibility key is set to true, you cannot enable reduced resources mode.

To Use the mediaLib Libraries on Solaris Systems

The mediaLib^TM libraries are a collection of functions that accelerate common multimedia operations. The Java Desktop System uses the mediaLib libraries if the libraries are installed on the system. The performance of the Java Desktop System, especially the file manager, improves significantly when the mediaLib libraries are installed. The Java Desktop System requires mediaLib version 2.0 or higher.

For information about how to obtain and install the mediaLib libraries, see the mediaLib website at the following URL:

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 Java Desktop System.

To Use Window Frame Theme Options 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 option that uses solid colors. That is, use one of the following window frame options:

Mist
Simple

For information about how to change theme options, see To Use Window Frame Theme Options 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 about how to turn off this feature, see To Reduce CPU Usage by Turning Off Display of Icons in Menus.

To Reduce Network Traffic by Enabling Reduced Resources Mode

If the application that displays the window is running on a remote host, enable reduced resources mode to reduce X Window System network traffic.

For more information about reduced resources mode, see To Reduce CPU Usage by Enabling Reduced Resources Mode.

Reducing Color Usage and Improving Display Quality on Solaris Systems

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 Java Desktop System 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 Java Desktop System 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 Java Desktop System for systems that support 8-bit color.

To Use Theme Options That Use the Websafe Color Palette

Some window frame theme options 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 window frame options on 8-bit color displays. Use Bright or Esco for the best color display on 8-bit visual modes.

For information about how to change theme options, see To Use Window Frame Theme Options 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 about 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 Java Desktop System and for applications.

For information about 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 Java Desktop System.

To set a solid color for the desktop background, execute 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 use the Desktop Background preference tool to choose a solid color for the desktop background.