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9.8 Improving Performance
This section discusses several preference settings you can
change to improve the performance of the GNOME Desktop. You can use
the gconftool-2 command to set values for preferences for users. The
example commands in this section 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. And you can 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 for Defaults.
9.8.1 Reducing CPU Usage
There are a number of preferences that you can set to reduce
CPU usage by the GNOME Desktop.
Using Theme Options That 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, but
can be slow on systems with limited CPU resources. To reduce CPU
usage, use one of the following window frame options:
The following window frame options also use fewer CPU
resources than Crux:
-
AgingGorilla
-
Bright
-
Metabox
HINT: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, use the following
command: gconftool-2 --type string --set /apps/metacity/general/theme option-name
For example, to use Atlanta, run the following command: gconftool-2 --type string --set /apps/metacity/general/theme Atlanta
Users can also use the Theme preference tool to select the
appropriate option.
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, use the following command: metacity-theme-viewer option-name
For example, to measure the performance of Atlanta and preview
Atlanta, use the following command: metacity-theme-viewer Atlanta
Turning Off Display of Icons in Menus
Some items in menus display an icon beside the item. To turn
off this feature, use the following command: gconftool-2 --type bool --set /desktop/gnome/interface/menus_have_icons false
Users can also use the Menus & Toolbars preference
tool to deselect the Show Icons in Menus option.
Turning Off the Splash Screen
When users log in to the desktop environment, a splash screen
is displayed by default. 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, use the following command: gconftool-2 --type bool --set /apps/gnome-session/options/show_splash_screen false
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, use the following
command: gconftool-2 --type bool --set /apps/panel/global/enable_animations false
Users can also 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.
Modifying Performance Preferences
The file manager includes performance-related preferences.
Each of these preference can take any of the following three
values.
Table 9-12 Performance-related Preferences
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always
|
Performs the action for both local files and files on
other file systems. |
|
local_only
|
Performs the action for local files only. Using this
value reduces CPU usage. |
|
never
|
Never performs the action. Using this value reduces CPU
usage and network traffic. |
The following table describes the performance preferences for
the file manager. For the fastest performance, set the value of
the preferences to Never.
Table 9-13 File Manager Performance Preferences
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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, use the following command: gconftool-2 --type string --set /apps/nautilus/preferences/ show_icon_text never
Users can also perform the following steps:
-
Click in a file
manager window, then click .
-
Select an option for the Show Text in Icons
preference.
|
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show_directory_item_counts
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Specifies when to show the number of items in folders.
To never show the number of items in folders, use the
following command: gconftool-2 --type string --set /apps/nautilus/preferences/ show_directory_item_counts never
Users can also perform the following steps:
-
Click in a file
manager window, then click .
-
Select an option for the Count Number of Items
preference.
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show_image_thumbnails
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Specifies when to show thumbnails of image files. To
never show thumbnails, use the following command: gconftool-2 --type string --set /apps/nautilus/preferences/ show_image_thumbnails never
Users can also perform the following steps:
-
Click in a file
manager window, then click .
-
Select an option for the Show Thumbnails preference.
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preview_sound
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Specifies when to preview the content of sound files. To
never preview the content of sound files, use the following
command: gconftool-2 --type string --set /apps/nautilus/preferences/preview_sound never
Users can also perform the following steps:
-
Click in a file
manager window, then click .
-
Select an option for the Preview Sound Files
preference.
|
Turning Off the Side Pane, Toolbar, and Location Bar
The file manager includes preferences that let you turn off
the side pane and the toolbar. Turning these off improves file
manager performance.
To turn off the side pane, use the following command: gconftool-2 --type bool --set /apps/nautilus/preferences/start_with_sidebar false
To turn off the toolbar, use 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, use the following command: gconftool-2 --type bool --set /apps/nautilus/preferences/start_with_location_bar false
Turning Off the Desktop
The file manager contains a preference that lets users use
Nautilus to manage the desktop. You can disable the desktop to
improve performance. However, if you disable the desktop, you
cannot
-
Use the Desktop menu.
-
Use the file manager to change the pattern or color of the
desktop background.
-
Use the desktop objects, such as Trash. (The desktop
objects are not displayed on the desktop.)
To disable the desktop, use the following command: gconftool-2 --type bool --set /apps/nautilus/preferences/show_desktop false
9.8.2 Reducing X Window System Network Traffic
There are some preferences that you can set to reduce X Window
System network traffic on the GNOME Desktop.
Using Theme Options That 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 one of the following
window frame options that uses solid colors:
For information on how to change theme options, see
Using Theme Options That Require Less CPU Resources.
Turning Off Display of Icons in Menus
Some items in menus display an icon beside the item. This
feature can increase X Window System network traffic if the icon is
located on another file system or if the panels are displayed on a
remote host.
For information on how to turn off this feature, see
Turning Off Display of Icons in Menus.
9.8.3 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 only 8-bit color (256 colors). The GNOME Desktop 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
GNOME Desktop are designed for systems that support 24-bit color.
The following display problems might occur on systems that
support only 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, which causes the grainy appearance.
-
Applications that do not use the websafe color palette have
fewer colors available; therefore, color errors might occur. Some
colors might not appear in the user interface of the application,
and 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 and
then become unviewable.
The following sections describe how to optimize the appearance
of the GNOME Desktop for systems that support only 8-bit color.
Using 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 and 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 on how to change theme options, see
Using Theme Options That Require Less CPU Resources.
Reducing 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
Turning Off Display of Icons in Menus.
Reducing Color Usage by Turning Off the Splash Screen
You can turn off the splash screen to make more colors
available for the GNOME Desktop and for applications.
For information on how to turn off the splash screen, see
Turning Off the Splash Screen.
Reducing Color Usage by Using a Solid Color for the
Background
Use a solid color for the desktop background. This reduces the
number of colors used by the GNOME Desktop.
To set a solid color for the background, use 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
Users can also use the Background preference tool to choose a
solid color for the background.
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