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<chapter id="performance-0">
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<title>Improving Performance</title>
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<para>This chapter describes how to improve the performance of
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the GNOME Desktop.</para>
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<sect1 id="performance-1">
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<title>Introduction to Improving Performance</title>
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<primary>performance, improving</primary>
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<secondary>introduction</secondary>
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<para>This chapter lists several preferences whose
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settings you can change to improve the performance of the GNOME Desktop. You
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can use the <command>gconftool-2</command> command to set values for preferences
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for users. The example commands in this chapter show how to set values in
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the user configuration source.</para>
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<para>You can also use the <literal>--direct</literal> and <literal>--config-source</literal> options to set mandatory values or default values for preferences.
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You can also use the <command>gconftool-2</command> command in a script to
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set the values of many preferences. For more information on the <command>gconftool-2</command> command and the options that are available with the
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command, see <xref linkend="gconf-0"/>.</para>
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<sect1 id="performance-8">
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<title>Reducing CPU Usage</title>
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<primary>performance, improving</primary>
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<secondary>reducing CPU
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<primary>reducing</primary>
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<secondary>CPU usage</secondary>
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<primary>CPU usage</primary>
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<secondary>reducing</secondary>
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<para>This section describes preferences that
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you can set to reduce CPU usage by the GNOME Desktop. </para>
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<sect2 id="performance-3">
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<title>To Use Theme Options Which Require Less CPU Resources</title>
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<primary>themes</primary>
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<secondary>window frame options</secondary>
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<tertiary>and CPU usage</tertiary>
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<primary>themes</primary>
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<secondary>and CPU usage</secondary>
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<para>Some window frame theme
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options load image files to draw the window frame. Other options use simpler
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techniques to draw the window frame.</para>
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<para>The Crux window frame option loads image files, and can be slow on systems
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with limited CPU resources. To reduce CPU usage, use one of the following
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window frame options: </para>
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<para>The following window frame options also use less CPU resources than
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<para>AgingGorilla</para>
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<para>Metabox does not work well with inverse controls options such
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as HighContrastInverse. Use Atlanta with inverse controls options.</para>
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<para><indexterm><primary>themes</primary><secondary>window frame options</secondary><tertiary>changing</tertiary></indexterm>To change the window
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frame theme option, run the following command: </para>
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<screen><userinput>gconftool-2 \
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--set /apps/metacity/general/theme <replaceable>option-name</replaceable></userinput></screen>
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<para>For example, to use Atlanta, run the following command:</para>
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<screen><userinput>gconftool-2 \
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--set /apps/metacity/general/theme Atlanta</userinput></screen>
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<para>Alternatively, users can use the <application>Theme</application> preference
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tool to select the appropriate option.</para>
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<para>You can use the <application>Metacity Theme Viewer</application>
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to measure the performance of a window frame option, and to preview the option.
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To start <application>Metacity Theme Viewer</application>, use the following
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<screen><userinput>metacity-theme-viewer <replaceable>option-name</replaceable></userinput></screen>
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<para>For example, to measure the performance of Atlanta and preview Atlanta,
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run the following command: </para>
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<screen><userinput>metacity-theme-viewer Atlanta</userinput></screen>
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<sect2 id="performance-2">
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<title>To Reduce CPU Usage by Turning Off Display of Icons in Menus</title>
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<primary>icons, in menus</primary>
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<see>menu icons</see>
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<primary>menu icons</primary>
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<secondary>and CPU usage</secondary>
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<primary>menu icons</primary>
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<secondary>turning off</secondary>
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<para>Some items in menus display an icon beside the
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item. To turn off this feature, run the following command: </para>
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<screen><userinput>gconftool-2 \
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--set /desktop/gnome/interface/menus_have_icons false</userinput></screen>
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<para>Alternatively, users can use the <application>Menus & Toolbars</application>
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preference tool to deselect the <guilabel>Show icons in menus</guilabel> option.</para>
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<sect2 id="performance-6">
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<title>To Reduce CPU Usage by Turning Off the Splash Screen</title>
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<primary>splash screen</primary>
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<secondary>and CPU usage</secondary>
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<para>By default, when users log in to the desktop environment,
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a splash screen is displayed. Icons are displayed on the splash screen while
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the user logs in. You can turn off the splash screen to reduce CPU usage during
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<para><indexterm><primary>splash screen</primary><secondary>turning off</secondary></indexterm>To turn off the splash screen, run the following command:</para>
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<screen><userinput>gconftool-2 \
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--set /apps/gnome-session/options/show_splash_screen false</userinput></screen>
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<para>Alternatively, users can use the <application>Sessions</application>
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preference tool to deselect the <guilabel>Show splash screen on login</guilabel>
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<sect2 id="performance-4">
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<title>To Reduce CPU Usage by Turning Off Panel Animation</title>
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<primary>panels</primary>
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<secondary>animation, turning off</secondary>
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<para>When users show or hide panels, the panels can show or hide
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in an animated style. To turn off panel animation, run the following command: </para>
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<screen><userinput>gconftool-2 \
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--set /apps/panel/global/enable_animations false</userinput></screen>
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<para>Alternatively, users can use the <application>Panel</application> preference
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tool to deselect the <guilabel>Drawer and panel animation</guilabel> option.</para>
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<sect2 id="performance-7">
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<title>Improving File Manager Performance</title>
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<primary>Nautilus</primary>
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<see>file manager</see>
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<para>The <application>Nautilus</application> file manager includes some features
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that you can modify to improve performance.</para>
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<sect3 id="performance-9">
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<title>To Modify Performance Preferences</title>
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<primary>file manager</primary>
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<secondary>modifying performance
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preferences</secondary>
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<para>The file manager includes performance-related
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preferences. Each performance preference can take one of three values. The
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values are described in the following table:</para>
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<informaltable frame="topbot">
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<tgroup cols="2" colsep="0" rowsep="0">
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<colspec colwidth="34.46*"/>
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<colspec colwidth="65.54*"/>
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<para>Description</para>
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<literal>always</literal>
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<para>Performs the action for both local files, and files on
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other file systems.</para>
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<literal>local_only</literal>
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<para>Performs the action for local files only. When you
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set a performance preference to <literal>local_only</literal>, the CPU usage
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<literal>never</literal>
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<para>Never performs the action. When you set a performance preference
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to never, the CPU usage and the network traffic are reduced.</para>
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<para>The following table describes the performance preferences for the file
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manager. For the fastest performance, set the value of the preferences to <literal>never</literal>.</para>
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<informaltable frame="topbot">
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<tgroup cols="2" colsep="0" rowsep="0">
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<colspec colwidth="43.34*"/>
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<colspec colwidth="56.66*"/>
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<para>Preference</para>
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<para>Description</para>
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<literal>show_icon_text</literal>
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<para>Specifies when to preview the content of text files
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in the icon that represents the file. To never preview the content of text
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files, run the following command: </para>
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<screen><userinput>gconftool-2 \
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--set /apps/nautilus/preferences/show_icon_text never</userinput></screen>
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<para>Alternatively, users can perform
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the following steps:</para>
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<para>Choose <menuchoice><guimenu>Edit</guimenu><guimenuitem>Preferences</guimenuitem></menuchoice> from a file manager window, then choose <guilabel>Preview</guilabel>.</para>
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<para>Select an option for the <guilabel>Show text in icons</guilabel>
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<literal>show_directory_item_counts</literal>
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<para>Specifies when to show the number of items in folders.
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To never show the number of items in folders, run the following command:</para>
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<screen><userinput>gconftool-2 \
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--set /apps/nautilus/preferences/show_directory_item_counts never</userinput></screen>
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<para>Alternatively, users can perform the following steps:</para>
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<para>Choose <menuchoice><guimenu>Edit</guimenu><guimenuitem>Preferences</guimenuitem></menuchoice> from a file manager window, then choose <guilabel>Preview</guilabel>.</para>
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<para>Select an option for the <guilabel>Count number of items</guilabel>
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<literal>show_image_thumbnails</literal>
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<para>Specifies when to show thumbnails of image files.
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To never show thumbnails, run the following command:</para>
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<screen><userinput>gconftool-2 \
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--set /apps/nautilus/preferences/show_image_thumbnails never</userinput></screen>
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<para>Alternatively, users can perform the following steps:</para>
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<para>Choose <menuchoice><guimenu>Edit</guimenu><guimenuitem>Preferences</guimenuitem></menuchoice> from a file manager window, then choose <guilabel>Preview</guilabel>.</para>
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<para>Select an option for the <guilabel>Show thumbnails</guilabel>
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<literal>preview_sound</literal>
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<para>Specifies when to preview the content of sound files.
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To never preview the content of sound files, run the following command:</para>
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<screen><userinput>gconftool-2 \
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--set /apps/nautilus/preferences/preview_sound never</userinput></screen>
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<para>Alternatively, users can perform the following
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<para>Choose <menuchoice><guimenu>Edit</guimenu><guimenuitem>Preferences</guimenuitem></menuchoice> from a file manager window, then choose <guilabel>Preview</guilabel>.</para>
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<para>Select an option for the <guilabel>Preview sound files</guilabel>
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<sect3 id="performance-10">
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<title>To Turn Off the Side Pane, Toolbar, and Location Bar</title>
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<primary>file manager</primary>
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<secondary>side pane, turning off</secondary>
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<para>The file manager includes preferences that enable
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you to turn off the side pane and the toolbar. To improve file manager performance,
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turn off the side pane and the toolbar.</para>
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<para>To turn off the side pane, run the following command: </para>
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<screen><userinput>gconftool-2 \
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--set /apps/nautilus/preferences/start_with_sidebar false</userinput></screen>
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<para><indexterm><primary>file manager</primary><secondary>toolbar, turning
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off</secondary></indexterm>To turn off the toolbar, run the following command: </para>
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<screen><userinput>gconftool-2 \
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--set /apps/nautilus/preferences/start_with_toolbar false</userinput></screen>
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<para>You can also turn off the location bar. Users can use the <keycombo><keycap>Ctrl</keycap><keycap>L</keycap></keycombo> keyboard shortcut to display a location bar
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when required. </para>
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<para><indexterm><primary>file manager</primary><secondary>location bar, turning
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off</secondary></indexterm>To turn off the location bar, run the following
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<screen><userinput>gconftool-2 \
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--set /apps/nautilus/preferences/start_with_location_bar false</userinput></screen>
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<sect3 id="performance-11">
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<title>To Turn Off the Desktop</title>
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<primary>file manager</primary>
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<secondary>desktop, turning off</secondary>
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<primary>desktop</primary>
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<para>The file manager contains a preference that
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enables users to use <application>Nautilus</application> to manage the desktop.
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You can disable the desktop to improve performance. However, if you disable
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the desktop, you cannot do the following:</para>
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<para>Use the <guimenu>Desktop</guimenu> menu.</para>
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<para>Use the file manager to change the pattern or color of the
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desktop background. </para>
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<para>Use the desktop objects, such as <guilabel>Trash</guilabel>.
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The desktop objects are not displayed on the desktop. </para>
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<para>To disable the desktop, run the following command: </para>
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<screen><userinput>gconftool-2 \
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--set /apps/nautilus/preferences/show_desktop false</userinput></screen>
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<sect1 id="performance-12">
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<title>Reducing X Window System Network Traffic</title>
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<primary>reducing</primary>
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<secondary>X Window System network traffic</secondary>
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<primary>X Window System network traffic,
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<primary>network traffic, reducing</primary>
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<para>This section describes preferences that you can
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set to reduce X Window System network traffic on the GNOME Desktop. </para>
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<sect2 id="performance-14">
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<title>To Use Theme Options Which Create Less Network Traffic</title>
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<primary>themes</primary>
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<secondary>window frame options</secondary>
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<tertiary>and network traffic</tertiary>
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<primary>themes</primary>
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<secondary>and network traffic</secondary>
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display protocols do not transfer every pixel in a block of pixels if all
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pixels in the block are the same color.</para>
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<para>To reduce X Window System network traffic, use a window frame theme
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option that uses solid colors. That is, use one of the following window frame
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<para>For information on how to change theme options, see <xref linkend="performance-3"/>.</para>
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<sect2 id="performance-15">
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<title>To Reduce Network Traffic by Turning Off Display of Icons in Menus</title>
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<primary>menu icons</primary>
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<secondary>and network traffic</secondary>
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<para>Some items in menus display an icon beside the item. If
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the icon is located on another file system, this feature can increase X Window
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System network traffic. This feature can also increase X Window System network
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traffic if the panels are displayed on a remote host. </para>
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<para>For information on how to turn off this feature, see <xref linkend="performance-2"/>.</para>
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<sect1 id="performance-17">
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<title>Reducing Color Usage and Improving Display Quality</title>
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<primary>reducing</primary>
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<secondary>color usage</secondary>
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<primary>color usage</primary>
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<secondary>reducing</secondary>
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<primary>display quality, improving</primary>
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<para>Many modern computer systems support 24-bit color, that is, 16,777,216 colors.
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However, many users still use systems that support 8-bit color, that is, 256
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<para>The GNOME Desktop uses the <firstterm>websafe color palette</firstterm>.
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This palette is a general-purpose palette of 216 colors, which is designed
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to optimize the use of color on systems that support 8-bit color. However,
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some visual components of the GNOME Desktop are designed for systems that
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support 24-bit color.</para>
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<para>The following display problems might occur on systems that support 8-bit
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<para>Windows, icons, and background images might appear grainy.
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Many themes, background images, and icons use colors that are not in the
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websafe color palette. The colors that are not in the palette are replaced
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with the nearest equivalent or a dithered approximation. This use of replacement
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colors causes the grainy appearance.</para>
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<para>Applications that do not use the websafe color palette have
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less colors available. Color errors might occur. Some colors might not appear
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in the user interface of the application. Some applications might crash if
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the application cannot allocate colors.</para>
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<para>Color flashing might occur when users switch between applications
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that use the websafe color palette, and applications that do not use this
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palette. The applications that do not use the websafe color palette might
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use a custom colormap. When the custom colormap is used, other visual components
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might lose colors, then become unviewable.</para>
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<para>The following sections describe how to optimize the appearance of the
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GNOME Desktop for systems that support 8-bit color. </para>
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<sect2 id="performance-20">
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<title>To Use Theme Options That Use the Websafe Color Palette</title>
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<primary>themes</primary>
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<secondary>window frame options</secondary>
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<tertiary>and color usage</tertiary>
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<primary>themes</primary>
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<secondary>and color usage</secondary>
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frame theme options use colors that are in the websafe color palette. Bright
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and Esco use colors from the websafe color palette. Bright and Esco do not
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have the grainy appearance of other window frame options on 8-bit color displays.
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Use Bright or Esco for the best color display on 8-bit visual modes. </para>
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<para>For information on how to change theme options, see <xref linkend="performance-3"/>.</para>
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<sect2 id="performance-21">
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<title>To Reduce Color Usage by Turning Off Display of Icons in Menus</title>
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<primary>menu icons</primary>
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<secondary>and color usage</secondary>
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<para>Some items in menus display an icon beside the item. If
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the icon contains colors that are not in the websafe color palette, this feature
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can increase the number of colors used.</para>
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<para>For information on how to turn off this feature, see <xref linkend="performance-2"/>.</para>
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<sect2 id="performance-18">
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<title>To Reduce Color Usage by Turning Off the Splash Screen</title>
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<primary>splash screen</primary>
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<secondary>and color usage</secondary>
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<para>You can turn off the splash screen to make more colors available
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for the GNOME Desktop and for applications.</para>
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<para>For information on how to turn off the splash screen, see <xref linkend="performance-6"/>.</para>
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<sect2 id="performance-19">
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<title>To Reduce Color Usage by Using a Solid Color for the Background</title>
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<primary>background</primary>
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<secondary>using solid color</secondary>
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<para>Use a solid color for the desktop background. Use of a solid
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color reduces the number of colors used by the GNOME Desktop. </para>
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<para>To set a solid color for the background, run the following commands: </para>
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<screen><userinput>gconftool-2 \
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--set /desktop/gnome/background/picture_options none</userinput></screen>
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<screen><userinput>gconftool-2 \
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--set /desktop/gnome/background/color_shading_type solid</userinput></screen>
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<screen><userinput>gconftool-2 \
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--set /desktop/gnome/background/primary_color #<replaceable>hexadecimal-color</replaceable></userinput></screen>
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<para>Alternatively, users can use the <application>Background</application>
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preference tool to choose a solid color for the background.</para>
added
removed
gnome2-system-admin-guide/C/performance.xml
