1126 lines
59 KiB
XML
1126 lines
59 KiB
XML
<!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<chapter id="platdev">
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<title>Platform Development with Poky</title>
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<section id="platdev-appdev">
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<title>Software development</title>
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<para>
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Poky supports several methods of software development. You can use the method that is
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best for you. This chapter describes each development method.
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</para>
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<section id="platdev-appdev-external-sdk">
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<title>External Development Using the Application Development Toolkit (ADT)</title>
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<para>
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The meta-toolchain and meta-toolchain-sdk targets build tarballs that contain toolchains and
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libraries suitable for application development outside of Poky.
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For information on these targets see the <ulink linkend='ref-images'>Reference: Images</ulink>
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appendix.
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</para>
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<para>
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These tarballs unpack into the
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<filename class="directory">/opt/poky</filename> directory and contain
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a setup script (e.g.
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<filename>/opt/poky/environment-setup-i586-poky-linux</filename>), from which
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you can source to initialize a suitable environment. Sourcing these files adds the
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compiler, QEMU scripts, QEMU binary, a special version of pkgconfig and other
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useful utilities to the PATH variable. Variables to assist pkgconfig and
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autotools are also defined so that, for example, configure can find pre-generated test
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results for tests that need target hardware on which to run.
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</para>
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<para>
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Using the toolchain with autotool-enabled packages is straightforward - just pass the
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appropriate host option to configure.
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Following is an example:
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<literallayout class='monospaced'>
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$ ./configure --host=arm-poky-linux-gnueabi
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</literallayout>
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For other projects it is usually a case of ensuring the cross tools are used:
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<literallayout class='monospaced'>
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CC=arm-poky-linux-gnueabi-gcc and LD=arm-poky-linux-gnueabi-ld
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</literallayout>
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</para>
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</section>
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<section id="using-the-eclipse-and-anjuta-plug-ins">
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<title>Using the Eclipse Plug-in</title>
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<para>
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The current release of the Yocto Project supports the Eclipse IDE plug-in
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to make developing software easier for the application developer.
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The plug-in provides capability extensions to the graphical IDE to allow
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for cross compilation, deployment and execution of the output in a QEMU
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emulation session.
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Support of the Eclipse plug-in also allows for cross debugging and
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profiling.
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Additionally, the Eclipse plug-in provides a suite of tools
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that allows the developer to perform remote profiling, tracing, collection of
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power data, collection of latency data and collection of performance data.
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</para>
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<note>
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The current release of the Yocto Project no longer supports the Anjuta plug-in.
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However, the Poky Anjuta Plug-in is available to download directly from the Poky
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Git repository located through the web interface at
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<ulink url="http://git.yoctoproject.org/"></ulink> under IDE Plugins.
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The community is free to continue supporting it beyond the Yocto Project 0.9
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Release.
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</note>
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<para>
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To use the Eclipse plug-in you need the Eclipse Framework (Helios 3.6.1) along
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with other plug-ins installed into the Eclipse IDE.
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Once you have your environment setup you need to configure the Eclipse plug-in.
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For information on how to install and configure the Eclipse plug-in, see the
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<ulink url='http://www.yoctoproject.org/docs/adt-manual/adt-manual.html#adt-eclipse'>
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"Working Within Eclipse"</ulink> chapter in the
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<ulink url='http://www.yoctoproject.org/docs/adt-manual/adt-manual.html'>
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"Application Development Toolkit (ADT) User's Guide."</ulink>
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</para>
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<!--
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<section id="the-eclipse-plug-in">
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<title>The Eclipse Plug-in</title>
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<para>
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To use the Eclipse plug-in, a toolchain and SDK built by Poky is required along with
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the Eclipse Framework (Helios 3.6.1).
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To install the plug-in you need to be in the Eclipse IDE and select
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the following menu:
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<literallayout class='monospaced'>
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Help -> Install New Software
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</literallayout>
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Specify the target URL as
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<ulink url='http://www.yoctoproject.org/downloads/eclipse-plugin/'></ulink>.
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</para>
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<para>
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If you want to download the source code for the plug-in you can find it in the Poky
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git repository, which has a web interface, and is located at
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<ulink url="http://git.yoctoproject.org"></ulink> under IDE Plugins.
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</para>
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<section id="installing-and-setting-up-the-eclipse-ide">
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||
<title>Installing and Setting up the Eclipse IDE</title>
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||
<para>
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If you don't have the Eclipse IDE (Helios 3.6.1) on your system you need to
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download and install it from <ulink url="http://www.eclipse.org/downloads"></ulink>.
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Choose the Eclipse Classic, which contains the Eclipse Platform, Java Development
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Tools (JDT), and the Plug-in Development Environment.
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</para>
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<note>
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<para>
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Due to the Java Virtual Machine's garbage collection (GC) process the
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permanent generation space (PermGen) is not cleaned up. This space stores
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meta-data descriptions of classes. The default value is set too small
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and it could trigger an out-of-memory error like the following:
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||
<literallayout class='monospaced'>
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||
Java.lang.OutOfMemoryError: PermGen space
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</literallayout>
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This error causes the applications to hang.
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</para>
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</note>
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<para>
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To fix this issue you can use the <filename>-vmargs</filename>
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option when you start Eclipse to increase the size of the permanent generation space:
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<literallayout class='monospaced'>
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Eclipse -vmargs -XX:PermSize=256M
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</literallayout>
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</para>
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</section>
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<section id="installing-the-yocto-plug-in">
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<title>Installing the Yocto Plug-in</title>
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<para>
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Once you have the Eclipse IDE installed and configured you need to install the
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Yocto plug-in. You do this similar to installing the Eclipse plug-ins in the
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previous section.
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</para>
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<para>
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Do the following to install the Yocto plug-in into the Eclipse IDE:
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<orderedlist>
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<listitem><para>Select the "Help -> Install New Software" item.</para></listitem>
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<listitem><para>In the "Work with:" area click "Add..." and enter the URL for
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the Yocto plug-in, which is
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<ulink url='http://www.yoctoproject.org/downloads/eclipse-plugin/'></ulink></para></listitem>
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<listitem><para>Finish out the installation of the update similar to any other
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Eclipse plug-in.</para></listitem>
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</orderedlist>
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</para>
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</section>
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<section id="configuring-yocto-eclipse-plug-in">
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<title>Configuring Yocto Eclipse plug-in</title>
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<para>
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To configure the Yocto Eclipse plug-in you need to select the mode and the
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architecture with which you will be working. Start by selecting "Preferences"
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from the "Window" menu and then select "Yocto SDK".
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</para>
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<para>
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If you normally will use an installed Yocto
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SDK (under <filename>/opt/poky</filename>) select “SDK Root Mode”. Otherwise, if your crosstool chain
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and sysroot are within your poky tree, select “Poky Tree Mode”.
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If you are in SDK Root Mode you need to provide your poky tree path, for
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example, <filename>$<Poky_tree>/build/</filename>.
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</para>
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<para>
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Next, you need to select the architecture.
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Use the drop down list and select the architecture that you’ll be primarily
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working against.
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For target option, select your typical target QEMU vs External hardware. If you
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choose QEMU, you’ll need to specify your QEMU kernel file with full path and the
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rootfs mount point. Yocto QEMU boots off user mode NFS.
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See the <link linkend='platdev-appdev-qemu'>Developing Externally in QEMU</link> section for
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how to set it up.
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</para>
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<para>
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To make your settings the defaults for every new Yocto project created using
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the Eclipse IDE, simply save the settings.
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</para>
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</section>
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<section id="using-the-yocto-eclipse-plug-in">
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<title>Using the Yocto Eclipse Plug-in</title>
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<para>
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As an example, this section shows you how to cross-compile a Yocto C project that
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is autotools-based, deploy the project into QEMU, and then run the debugger against it.
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You need to configure the project, trigger the <filename> autogen.sh</filename>, build
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the image, start QEMU, and then debug.
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</para>
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<para>
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The following steps show how to create a Yocto autotools-based project using a given template:
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</para>
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<orderedlist>
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<listitem><para>Select "File -> New -> Project" to start the wizard.</para></listitem>
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<listitem><para>Expand "C/C++" and select "C Project".</para></listitem>
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<listitem><para>Click "Next" and select a template (e.g. "Hello World ANSI C Project").</para></listitem>
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<listitem><para>Complete the steps to create the new Yocto autotools-based project using
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your chosen template.</para></listitem>
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</orderedlist>
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<para>
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By default, the project uses the Yocto preferences settings as defined using the procedure in
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<link linkend="configuring-yocto-eclipse-plug-in">the previous section</link>.
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If there are any specific setup requirements for the newly created project
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you need to reconfigure the Yocto plug-in through the menu selection by doing the following:
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</para>
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<orderedlist>
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<listitem><para>Select the "Project -> Invoke Yocto Tools -> Reconfigure Yocto" menu item.</para></listitem>
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<listitem><para>Complete the dialogue to specify the specific toolchain and QEMU setup information.</para></listitem>
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</orderedlist>
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<para>
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To build the project follow these steps:
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</para>
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<orderedlist>
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<listitem><para>Select "Project -> Reconfigure Project" to trigger the
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<filename>autogen.sh</filename> command.</para></listitem>
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<listitem><para>Select "Project -> Build" to build the project.</para></listitem>
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</orderedlist>
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<para>
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To start QEMU follow these steps:
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</para>
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<orderedlist>
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<listitem><para>Select "Run -> External Tools" and see if there is
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a QEMU instance for the desired target.
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If one exists, click on the instance to start QEMU.
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If your target does not exist, click "External Tools Configuration" and
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you should find an instance of QEMU for your architecture
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under the entry under "Program".</para></listitem>
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<listitem><para>Wait for the boot to complete.</para></listitem>
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</orderedlist>
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<para>
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To deploy your project and start debugging follow these steps:
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</para>
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<orderedlist>
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<listitem><para>Highlight your project in the project explorer.</para></listitem>
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<listitem><para>Select "Run -> Debug Configurations" to bring up your remote debugging configuration
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in the right-hand window.</para></listitem>
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<listitem><para>Expand “C/C++ Remote Application”.</para></listitem>
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<listitem><para>Select "projectname_ gdb_target-poky-linux".
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You need to be sure there is an entry for the remote target.
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If no entry exists, click "New..." to bring up the wizard.
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Use the wizard to select TCF and enter the IP address of you remote target in the
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“Host name:” field.
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Back in the Remote Debug Configure window, specify in the
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“Remote Absolute File Path for C/C++ Application” field the absolute path for the program on
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the remote target.
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By default, the program deploys into the remote target.
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If you don't want this behavior then check “Skip download to target path”.</para></listitem>
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<listitem><para>Click "Debug” to start the remote debugging session.</para></listitem>
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</orderedlist>
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||
</section>
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||
|
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<section id="using-yocto-eclipse-plug-in-remote-tools-suite">
|
||
<title>Using Yocto Eclipse plug-in Remote Tools Suite</title>
|
||
<para>
|
||
Remote tools allow you to perform system profiling, kernel tracing,
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examine power consumption, and so forth. To see and access the remote tools use the
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"Window -> YoctoTools" menu.
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||
</para>
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<para>
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Once you pick a tool you need to configure it for the remote target. Every tool
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needs to have the connection configured. You must select an existing TCF-based
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RSE connection to the remote target. If one does not exist, click "New" to create one.
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</para>
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<para>
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Here are some specifics about the remote tools:
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<itemizedlist>
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<listitem><para>OProfile: Selecting this tool causes the oprofile-server on the remote
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target to launch on the local host machine. The oprofile-viewer
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||
must be installed on the local host machine and the oprofile-server must be
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installed on the remote target, respectively, in order to use .</para></listitem>
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<listitem><para>lttng: Selecting this tool runs "usttrace" on the remote target, transfers
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the output data back to the local host machine and uses "lttv-gui" to graphically
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display the output. The "lttv-gui" must be installed on the
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local host machine to use this tool.
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For information on how to use "lttng" to trace an
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application, see <ulink url="http://lttng.org/files/ust/manual/ust.html"></ulink>.
|
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<para>
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For "Application" you must supply the absolute path name of the application to
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be traced by user mode lttng. For example, typing <filename>/path/to/foo"
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</filename> triggers "usttrace /path/to/foo" on the
|
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remote target to trace the program <filename>/path/to/foo</filename>.
|
||
</para>
|
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<para>
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"Argument" is passed to "usttrace" running on the remote target.
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</para></para>
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</listitem>
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<listitem><para>powertop: Selecting this tool runs "powertop" on the
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remote target machine and displays the results in a new view called "powertop".
|
||
<para>
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"Time to gather data(sec):" is the time passed in seconds before data is
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gathered from the remote target for analysis.
|
||
</para>
|
||
<para>
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||
"show pids in wakeups list:" corresponds to the <filename>-p</filename>
|
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argument passed to "powertop".
|
||
</para></para>
|
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</listitem>
|
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<listitem><para>latencytop and perf: "latencytop" identifies
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system latency, while "perf" monitors the system's performance
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counter registers. Selecting either of these tools causes an RSE
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||
terminal view to appear from which you can run the tools. Both tools refresh the
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||
entire screen to display results while they run.</para></listitem>
|
||
</itemizedlist>
|
||
</para>
|
||
</section>
|
||
</section>
|
||
|
||
<section id="the-anjuta-plug-in">
|
||
<title>The Anjuta Plug-in</title>
|
||
<note>
|
||
<para>
|
||
Support for the Anjuta plug-in ends after Yocto project 0.9 Release.
|
||
However, the source code can be downloaded from the git repository listed later in
|
||
this section.
|
||
The community is free to continue supporting it post 0.9 Release.
|
||
</para>
|
||
</note>
|
||
<para>
|
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An Anjuta IDE plug-in exists to make developing software within the Poky framework
|
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easier for the application developer familiar with that environment.
|
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The plug-in presents a graphical IDE that allows you to cross-compile, cross-debug,
|
||
profile, deploy, and execute an application.
|
||
</para>
|
||
<para>
|
||
To use the plug-in, a toolchain and SDK built by Poky, Anjuta, its development headers and the Anjuta
|
||
Plug-in are all required.
|
||
The Poky Anjuta Plug-in is available to download as a tarball at the OpenedHand
|
||
labs <ulink url="http://labs.o-hand.com/anjuta-poky-sdk-plugin/"></ulink> page or
|
||
directly from the Poky Git repository located at git://git.yoctoproject.org/anjuta-poky.
|
||
You can access the source code from a web interface to the repository at
|
||
<ulink url="http://git.yoctoproject.org/"></ulink> under IDE Plugins.
|
||
</para>
|
||
<para>
|
||
See the README file contained in the project for more information on
|
||
Anjuta dependencies and building the plug-in.
|
||
If you want to disable remote gdb debugging, pass the "‐‐disable-gdb-integration" switch when
|
||
you configure the plug-in.
|
||
</para>
|
||
<section id="setting-up-the-anjuta-plugin">
|
||
<title>Setting Up the Anjuta Plug-in</title>
|
||
<para>
|
||
Follow these steps to set up the plug-in:
|
||
<orderedlist>
|
||
<listitem><para>Extract the tarball for the toolchain into / as root.
|
||
The toolchain will be installed into <filename>/opt/poky</filename>.</para></listitem>
|
||
<listitem><para>To use the plug-in, first open or create an existing project.
|
||
If you are creating a new project, the "C GTK+"
|
||
project type will allow itself to be cross-compiled.
|
||
However, you should be aware that this type uses "glade" for the UI.</para></listitem>
|
||
<listitem><para>To activate the plug-in, select "Edit -> Preferences" and then choose
|
||
"General" from the left hand side.
|
||
Choose the "Installed plug-ins" tab, scroll down to "Poky SDK" and
|
||
check the box.</para></listitem>
|
||
</orderedlist>
|
||
The plug-in is now activated but not configured.
|
||
</para>
|
||
</section>
|
||
<section id="configuring-the-anjuta-plugin">
|
||
<title>Configuring the Anjuta Plug-in</title>
|
||
<para>
|
||
You can find the configuration options for the SDK by choosing the Poky
|
||
SDK icon from the left hand side.
|
||
You need to define the following options:
|
||
<itemizedlist>
|
||
<listitem><para>SDK root: If you use an external toolchain you need to set
|
||
SDK root, which is the root directory of the SDK's sysroot.
|
||
For an i586 SDK directory is <filename>/opt/poky/</filename>.
|
||
This directory will contain "bin", "include", "var" and so forth under your
|
||
selected target architecture subdirectory
|
||
<filename>/opt/poky/sysroot/i586-poky-linux/</filename>.
|
||
The cross-compile tools you need are in
|
||
<filename>/opt/poky/sysroot/i586-pokysdk-linux/</filename>.</para></listitem>
|
||
<listitem><para>Poky root: If you have a local Poky build tree, you need to
|
||
set the Poky root, which is the root directory of the poky build tree.
|
||
If you build your i586 target architecture under the subdirectory of
|
||
<filename>build_x86</filename> within your Poky tree, the Poky root directory
|
||
should be <filename>$<poky_tree>/build_x86/</filename>.</para></listitem>
|
||
<listitem><para>Target Architecture: This is the cross compile triplet,
|
||
for example, "i586-poky-linux".
|
||
This target triplet is the prefix extracted from the set up script file's name.
|
||
For example, if the script file name is
|
||
<filename>/opt/poky/environment-setup-i586-poky-linux</filename> then the extracted target
|
||
triplet is "i586-poky-linux".</para></listitem>
|
||
<listitem><para>Kernel: Use the file chooser to select the kernel used with QEMU.</para></listitem>
|
||
<listitem><para>Root filesystem: Use the file chooser to select the root
|
||
filesystem directory. This directory is where you use "poky-extract-sdk" to extract the
|
||
core-image-sdk tarball.</para></listitem>
|
||
</itemizedlist>
|
||
</para>
|
||
</section>
|
||
<section id="using-the-anjuta-plug-in">
|
||
<title>Using the Anjuta Plug-in</title>
|
||
<para>
|
||
The steps in this section show how to cross-compile a project, deploy it into
|
||
QEMU, run a debugger against it and then perform a system-wide profile.
|
||
<orderedlist>
|
||
<listitem><para>Choose "Build -> Run Configure" or "Build -> Run Autogenerate" to run
|
||
"configure" or "autogen", respectively for the project.
|
||
Either command passes command-line arguments to instruct the
|
||
cross-compile.</para></listitem>
|
||
<listitem><para>Choose "Build -> Build Project" to build and compile the project.
|
||
If you have previously built the project in the same tree without using
|
||
the cross-compiler you might find that your project fails to link.
|
||
If this is the case, simply select "Build -> Clean Project" to remove the
|
||
old binaries.
|
||
After you clean the project you can then try building it again.</para></listitem>
|
||
<listitem><para>Choose "Tools -> Start QEMU" to start QEMU.
|
||
After QEMU starts any error messages will appear in the message view.
|
||
Once Poky has fully booted within QEMU you can deploy the project
|
||
into it.</para></listitem>
|
||
<listitem><para>Once the project is built and you have QEMU running choose
|
||
"Tools -> Deploy" to install the package into a temporary
|
||
directory and then copy it using "rsync" over SSH into the target.
|
||
A progress bar and appropriate messages appear in the message view.</para></listitem>
|
||
<listitem><para>To debug a program installed onto the target choose
|
||
"Tools -> Debug remote".
|
||
Choosing this menu item causes prompts to appear to define the local binary
|
||
for debugging and also for the command line used to run on the target.
|
||
When you provide the command line be sure to include the full path to the to binary
|
||
installed in the target.
|
||
When the command line runs a "gdbserver" over SSH is started on the target and
|
||
an instance of "cross-gdb" starts in a local terminal.
|
||
The instance of "cross-gdb" will be preloaded to connect to the server and use the SDK root to
|
||
find symbols.
|
||
It also connects to the target and loads in various libraries as well as the
|
||
target program.
|
||
You should define any breakpoints or watchpoints at this point in the process since you might not
|
||
be able to interrupt the execution later.
|
||
To stop the debugger on the target choose "Tools -> Stop debugger".</para></listitem>
|
||
<listitem><para>It is also possible to execute a command in the target over SSH.
|
||
Doing so causes the appropriate environment to be established for execution.
|
||
To execute a command choose "Choose Tools -> Run remote".
|
||
This selection opens a terminal with the SSH command inside.</para></listitem>
|
||
<listitem><para>To perform a system-wide profile against the system running in QEMU choose
|
||
"Tools -> Profile remote".
|
||
This choice starts up "OProfileUI" with the appropriate parameters to
|
||
connect to the server running inside QEMU and also supplies the path
|
||
for debug information necessary to get a useful profile.</para></listitem>
|
||
</orderedlist>
|
||
</para>
|
||
</section>
|
||
</section>
|
||
|
||
|
||
-->
|
||
|
||
</section>
|
||
|
||
<section id="platdev-appdev-qemu">
|
||
<title>Developing Externally in QEMU</title>
|
||
<para>
|
||
Running Poky QEMU images is covered in the
|
||
<ulink url="http://www.yoctoproject.org/docs/yocto-quick-start/yocto-project-qs.html">
|
||
Yocto Project Quick Start</ulink> in the "A Quick Test Run" section.
|
||
</para>
|
||
<para>
|
||
Poky's QEMU images contain a complete native toolchain. This means
|
||
you can develop applications within QEMU similar to the way you would in a normal system.
|
||
Using qemux86 on an x86 machine is fast since the
|
||
guest and host architectures match.
|
||
On the other hand, using qemuarm can be slower but gives
|
||
faithful emulation of ARM-specific issues. To speed things up, these
|
||
images support using "distcc" to call a cross-compiler outside the
|
||
emulated system. If "runqemu" was used to start
|
||
QEMU, and "distccd" is present on the host system, any Bitbake cross-compiling
|
||
toolchain available from the build system is automatically
|
||
used from within QEMU simply by calling "distcc". You can accomplish this by defining the
|
||
cross-compiler variable (e.g. <filename>export CC="distcc"</filename>).
|
||
Alternatively, if a suitable SDK/toolchain is present in
|
||
<filename>/opt/poky</filename> it is also
|
||
automatically be used.
|
||
</para>
|
||
|
||
<para>
|
||
There are several options for connecting into the emulated system.
|
||
QEMU provides a framebuffer interface that has standard consoles
|
||
available. There is also a serial connection available that has a
|
||
console to the system running on it and uses standard IP networking.
|
||
The images have a dropbear ssh server running with the root password
|
||
disabled to allow standard ssh and scp commands to work. The images
|
||
also contain an NFS server that exports the guest's root filesystem, which
|
||
allows it to be made available to the host.
|
||
</para>
|
||
</section>
|
||
|
||
<section id="platdev-appdev-insitu">
|
||
<title>Developing in Poky Directly</title>
|
||
<para>
|
||
Working directly in Poky is a fast and effective development technique.
|
||
The idea is that you can directly edit files in
|
||
<glossterm><link linkend='var-WORKDIR'>WORKDIR</link></glossterm>
|
||
or the source directory <glossterm><link linkend='var-S'>S</link></glossterm>
|
||
and then force specific tasks to rerun in order to test the changes.
|
||
An example session working on the matchbox-desktop package might
|
||
look like this:
|
||
</para>
|
||
|
||
<para>
|
||
<literallayout class='monospaced'>
|
||
$ bitbake matchbox-desktop
|
||
$ sh
|
||
$ cd tmp/work/armv5te-poky-linux-gnueabi/matchbox-desktop-2.0+svnr1708-r0/
|
||
$ cd matchbox-desktop-2
|
||
$ vi src/main.c
|
||
$ exit
|
||
$ bitbake matchbox-desktop -c compile -f
|
||
$ bitbake matchbox-desktop
|
||
</literallayout>
|
||
</para>
|
||
|
||
<para>
|
||
This example builds the package, changes into the work directory for the package,
|
||
changes a file, then recompiles the package. Instead of using "sh" as it is in the example,
|
||
you can also use two different terminals. However, the risk of using two terminals
|
||
is that a command like "unpack" could destroy the changes you've made to the
|
||
work directory. Consequently, you need to work carefully.
|
||
</para>
|
||
|
||
<para>
|
||
It is useful when making changes directly to the work directory files to do
|
||
so using "quilt" as detailed in the <link linkend='usingpoky-modifying-packages-quilt'>
|
||
modifying packages with quilt</link> section. You can copy the resulting patches
|
||
into the recipe directory and use them directly in the <glossterm><link
|
||
linkend='var-SRC_URI'>SRC_URI</link></glossterm>.
|
||
</para>
|
||
<para>
|
||
For a review of the skills used in this section see the <link
|
||
linkend="usingpoky-components-bitbake">Bitbake</link> and <link
|
||
linkend="usingpoky-debugging-taskrunning">Running Specific Tasks</link> Sections.
|
||
</para>
|
||
</section>
|
||
|
||
<section id="platdev-appdev-devshell">
|
||
<title>Developing with 'devshell'</title>
|
||
|
||
<para>
|
||
When debugging certain commands or even when just editing packages, the
|
||
'devshell' can be a useful tool.
|
||
Use a command like the following to start this tool.
|
||
</para>
|
||
|
||
<para>
|
||
<literallayout class='monospaced'>
|
||
$ bitbake matchbox-desktop -c devshell
|
||
</literallayout>
|
||
</para>
|
||
|
||
<para>
|
||
This command opens a terminal with a shell prompt within the Poky
|
||
environment. Consequently, the following occurs:
|
||
<itemizedlist>
|
||
<listitem><para>The PATH variable includes the cross toolchain.</para></listitem>
|
||
<listitem><para>The pkgconfig variables find the correct <filename>.pc</filename> files.</para></listitem>
|
||
<listitem><para>"configure" finds the Poky site files as well as any other necessary files.</para></listitem>
|
||
</itemizedlist>
|
||
Within this environment, you can run "configure" or "compile" commands as if they
|
||
were being run by Poky itself.
|
||
The working directory also automatically changes to the (<glossterm><link linkend='var-S'>S</link></glossterm>)
|
||
directory.
|
||
When you are finished, you just exit the shell or close the terminal window.
|
||
</para>
|
||
|
||
<para>
|
||
The default shell used by "devshell" is the gnome-terminal.
|
||
You can use other forms of terminal can by setting the <glossterm>
|
||
<link linkend='var-TERMCMD'>TERMCMD</link></glossterm> and <glossterm>
|
||
<link linkend='var-TERMCMDRUN'>TERMCMDRUN</link></glossterm> variables
|
||
in <filename>local.conf</filename>.
|
||
For examples of the other options available, see
|
||
<filename>meta/conf/bitbake.conf</filename>.
|
||
</para>
|
||
<para>
|
||
An external shell is launched rather than opening directly into the original terminal
|
||
window.
|
||
This allows easier interaction with Bitbake's multiple threads as well as
|
||
for a future client/server split.
|
||
Note that "devshell" will still work over X11 forwarding or similar situations.
|
||
</para>
|
||
|
||
<para>
|
||
It is worth remembering that inside "devshell" you need to use the full
|
||
compiler name such as <filename>arm-poky-linux-gnueabi-gcc</filename>
|
||
instead of just <filename>gcc</filename>.
|
||
The same applies to other applications such as gcc, bintuils, libtool and so forth.
|
||
Poky will have setup environmental variables such as CC to assist applications, such as make,
|
||
find the correct tools.
|
||
</para>
|
||
</section>
|
||
|
||
<section id="platdev-appdev-srcrev">
|
||
<title>Developing within Poky with an External SCM-based Package</title>
|
||
|
||
<para>
|
||
If you're working on a recipe that pulls from an external SCM it
|
||
is possible to have Poky notice new changes added to the
|
||
SCM and then build the latest version using them.
|
||
This only works for SCMs from which it is possible to get a sensible revision number for changes.
|
||
Currently it works for svn, git and bzr repositories.
|
||
</para>
|
||
|
||
<para>
|
||
To enable this behavior simply add <glossterm>
|
||
<link linkend='var-SRCREV'>SRCREV</link></glossterm>_pn-<glossterm>
|
||
<link linkend='var-PN'>PN</link></glossterm> = "${AUTOREV}" to
|
||
<filename>local.conf</filename>, where <glossterm><link linkend='var-PN'>PN</link></glossterm>
|
||
is the name of the package for which you want to enable automatic source
|
||
revision updating.
|
||
</para>
|
||
</section>
|
||
</section>
|
||
|
||
<section id="platdev-gdb-remotedebug">
|
||
<title>Debugging with GDB Remotely</title>
|
||
|
||
<para>
|
||
GNU Project Debugger (GDB)
|
||
allows you to examine running programs to understand and fix problems and
|
||
also to perform post-mortem style analysis of program crashes.
|
||
GDB is available as a package within Poky and by default is installed in sdk images.
|
||
See <ulink url="http://sourceware.org/gdb/"/> for the GDB source.
|
||
</para>
|
||
<tip><para>
|
||
For best results install <filename>-dbg</filename> packages for the applications
|
||
you are going to debug.
|
||
Doing so makes available extra debug symbols that will give you more meaningful output.
|
||
</para></tip>
|
||
|
||
<para>
|
||
Sometimes, due to memory or disk space constraints, it is not possible
|
||
to use GDB directly on the remote target to debug applications.
|
||
These constraints arise because GDB needs to load the debugging information and the
|
||
binaries of the process being debugged.
|
||
Additionally, GDB needs to perform many computations to locate information such as function
|
||
names, variable names and values, stack traces and so forth - even before starting the
|
||
debugging process.
|
||
These extra computations place more load on the target system and can alter the
|
||
characteristics of the program being debugged.
|
||
</para>
|
||
<para>
|
||
To help get past these constraints you can use GDBSERVER.
|
||
It runs on the remote target and does not load any debugging information
|
||
from the debugged process.
|
||
Instead, a GDB instance processes the debugging information that is run on a
|
||
remote computer - the host GDB.
|
||
The host GDB then sends control commands to GDBSERVER to make it stop or start the debugged
|
||
program, as well as read or write memory regions of that debugged
|
||
program.
|
||
All the debugging information loaded and processed as well
|
||
as all the heavy debugging is done by the host GDB.
|
||
Offloading these processes gives the GDBSERVER running on the target a chance to remain
|
||
small and fast.
|
||
</para>
|
||
<para>
|
||
Because the host GDB is responsible for loading the debugging information and
|
||
for doing the necessary processing to make actual debugging happen, the
|
||
user has to make sure the host can access the unstripped binaries complete
|
||
with their debugging information and also compiled with no optimizations.
|
||
The host GDB must also have local access to all the libraries used by the
|
||
debugged program.
|
||
Because GDBSERVER does not need any local debugging information the binaries on
|
||
the remote target can remain stripped.
|
||
However, the binaries must also be compiled without optimization
|
||
so they match the host's binaries.
|
||
</para>
|
||
|
||
<para>
|
||
To remain consistent with GDB documentation and terminology the binary being debugged
|
||
on the remote target machine is referred to as the 'inferior' binary.
|
||
For documentation on GDB see the GDB site at
|
||
<ulink url="http://sourceware.org/gdb/documentation/">on their site</ulink>.
|
||
</para>
|
||
|
||
<section id="platdev-gdb-remotedebug-launch-gdbserver">
|
||
<title>Launching GDBSERVER on the Target</title>
|
||
<para>
|
||
First, make sure GDBSERVER is installed on the target. If not,
|
||
install the package <filename>gdbserver</filename>, which needs the
|
||
<filename>libthread-db1</filename> package.
|
||
</para>
|
||
<para>
|
||
As an example, to launch GDBSERVER on the target and make it ready to "debug" a
|
||
program located at <filename>/path/to/inferior</filename>, connect
|
||
to the target and launch:
|
||
<literallayout class='monospaced'>
|
||
$ gdbserver localhost:2345 /path/to/inferior
|
||
</literallayout>
|
||
GDBSERVER should now be listening on port 2345 for debugging
|
||
commands coming from a remote GDB process that is running on the host computer.
|
||
Communication between GDBSERVER and the host GDB are done using TCP.
|
||
To use other communication protocols please refer to the GDBSERVER documentation.
|
||
</para>
|
||
</section>
|
||
|
||
<section id="platdev-gdb-remotedebug-launch-gdb">
|
||
<title>Launching GDB on the Host Computer</title>
|
||
|
||
<para>
|
||
Running GDB on the host computer takes a number of stages.
|
||
This section describes those stages.
|
||
</para>
|
||
|
||
<section id="platdev-gdb-remotedebug-launch-gdb-buildcross">
|
||
<title>Building the Cross-GDB Package</title>
|
||
<para>
|
||
A suitable GDB cross-binary is required that runs on your host computer but
|
||
also knows about the the ABI of the remote target.
|
||
You can get this binary from the the Poky toolchain - for example:
|
||
<programlisting>
|
||
/usr/local/poky/eabi-glibc/arm/bin/arm-poky-linux-gnueabi-gdb
|
||
</programlisting>
|
||
where "arm" is the target architecture and "linux-gnueabi" the target ABI.
|
||
</para>
|
||
|
||
<para>
|
||
Alternatively, Poky can build the <filename>gdb-cross</filename> binary.
|
||
For example, the following command builds it:
|
||
<literallayout class='monospaced'>
|
||
$ bitbake gdb-cross
|
||
</literallayout>
|
||
Once the binary is built you can find it here:
|
||
<programlisting>
|
||
tmp/sysroots/<host-arch>/usr/bin/<target-abi>-gdb
|
||
</programlisting>
|
||
</para>
|
||
|
||
</section>
|
||
<section id="platdev-gdb-remotedebug-launch-gdb-inferiorbins">
|
||
|
||
<title>Making the Inferior Binaries Available</title>
|
||
|
||
<para>
|
||
The inferior binary (complete with all debugging symbols) as well as any
|
||
libraries (and their debugging symbols) on which the inferior binary depends
|
||
need to be available.
|
||
There are a number of ways you can make these available.
|
||
</para>
|
||
|
||
<para>
|
||
Perhaps the easiest is to have an 'sdk' image that corresponds to the plain
|
||
image installed on the device.
|
||
In the case of 'core-image-sato', 'core-image-sdk' would contain suitable symbols.
|
||
Because the sdk images already have the debugging symbols installed it is just a
|
||
question of expanding the archive to some location and then informing GDB.
|
||
</para>
|
||
|
||
<para>
|
||
Alternatively, Poky can build a custom directory of files for a specific
|
||
debugging purpose by reusing its <filename>tmp/rootfs</filename> directory.
|
||
This directory contains the contents of the last built image.
|
||
This process assumes two things:
|
||
<itemizedlist>
|
||
<listitem><para>The image running on the target was the last image to
|
||
be built by Poky.</para></listitem>
|
||
<listitem><para>The package (<filename>foo</filename> in the following
|
||
example) that contains the inferior binary to be debugged has been built
|
||
without optimization and has debugging information available.</para></listitem>
|
||
</itemizedlist>
|
||
</para>
|
||
<para>
|
||
These steps show how to build the custom directory of files:
|
||
</para>
|
||
<orderedlist>
|
||
<listitem><para>Install the package (<filename>foo</filename> in this case) to
|
||
<filename>tmp/rootfs</filename>:
|
||
<programlisting>
|
||
tmp/sysroots/i686-linux/usr/bin/opkg-cl -f \
|
||
tmp/work/<target-abi>/core-image-sato-1.0-r0/temp/opkg.conf -o \
|
||
tmp/rootfs/ update
|
||
</programlisting></para></listitem>
|
||
<listitem><para>Install the debugging information:
|
||
<programlisting>
|
||
tmp/sysroots/i686-linux/usr/bin/opkg-cl -f \
|
||
tmp/work/<target-abi>/core-image-sato-1.0-r0/temp/opkg.conf \
|
||
-o tmp/rootfs install foo
|
||
|
||
tmp/sysroots/i686-linux/usr/bin/opkg-cl -f \
|
||
tmp/work/<target-abi>/core-image-sato-1.0-r0/temp/opkg.conf \
|
||
-o tmp/rootfs install foo-dbg
|
||
</programlisting></para></listitem>
|
||
</orderedlist>
|
||
|
||
</section>
|
||
<section id="platdev-gdb-remotedebug-launch-gdb-launchhost">
|
||
|
||
<title>Launch the Host GDB</title>
|
||
<para>
|
||
To launch the host GDB, you run the cross-gdb binary and provide the inferior
|
||
binary as part of the command line.
|
||
For example, the following command form continues with the example used in
|
||
the previous section.
|
||
This command form loads the <filename>foo</filename> binary
|
||
as well as the debugging information:
|
||
<literallayout class='monospaced'>
|
||
$ <target-abi>-gdb rootfs/usr/bin/foo
|
||
</literallayout>
|
||
Once the GDB prompt appears, you must instruct GDB to load all the libraries
|
||
of the inferior binary from <filename>tmp/rootfs</filename> as follows:
|
||
<literallayout class='monospaced'>
|
||
$ set solib-absolute-prefix /path/to/tmp/rootfs
|
||
</literallayout>
|
||
The pathname <filename>/path/to/tmp/rootfs</filename> must either be
|
||
the absolute path to <filename>tmp/rootfs</filename> or the location at which
|
||
binaries with debugging information reside.
|
||
</para>
|
||
<para>
|
||
At this point you can have GDB connect to the GDBSERVER that is running
|
||
on the remote target by using the following command form:
|
||
<literallayout class='monospaced'>
|
||
$ target remote remote-target-ip-address:2345
|
||
</literallayout>
|
||
The <filename>remote-target-ip-address</filename> is the IP address of the
|
||
remote target where the GDBSERVER is running.
|
||
Port 2345 is the port on which the GDBSERVER is running.
|
||
</para>
|
||
|
||
</section>
|
||
<section id="platdev-gdb-remotedebug-launch-gdb-using">
|
||
|
||
<title>Using the Debugger</title>
|
||
<para>
|
||
You can now proceed with debugging as normal - as if you were debugging
|
||
on the local machine.
|
||
For example, to instruct GDB to break in the "main" function and then
|
||
continue with execution of the inferior binary use the following commands
|
||
from within GDB:
|
||
<literallayout class='monospaced'>
|
||
(gdb) break main
|
||
(gdb) continue
|
||
</literallayout>
|
||
</para>
|
||
<para>
|
||
For more information about using GDB, see the project's online documentation at
|
||
<ulink url="http://sourceware.org/gdb/download/onlinedocs/"/>.
|
||
</para>
|
||
</section>
|
||
</section>
|
||
|
||
</section>
|
||
|
||
<section id="platdev-oprofile">
|
||
<title>Profiling with OProfile</title>
|
||
|
||
<para>
|
||
<ulink url="http://oprofile.sourceforge.net/">OProfile</ulink> is a
|
||
statistical profiler well suited for finding performance
|
||
bottlenecks in both userspace software and in the kernel.
|
||
This profiler provides answers to questions like "Which functions does my application spend
|
||
the most time in when doing X?"
|
||
Because Poky is well integrated with OProfile it makes profiling applications on target
|
||
hardware straightforward.
|
||
</para>
|
||
|
||
<para>
|
||
To use OProfile you need an image that has OProfile installed.
|
||
The easiest way to do this is with "tools-profile" in
|
||
<glossterm><link linkend='var-IMAGE_FEATURES'>IMAGE_FEATURES</link></glossterm>.
|
||
You also need debugging symbols to be available on the system where the analysis
|
||
takes place.
|
||
You can gain access to the symbols by using "dbg-pkgs" in
|
||
<glossterm><link linkend='var-IMAGE_FEATURES'>IMAGE_FEATURES</link></glossterm> or by
|
||
installing the appropriate <filename>-dbg</filename> packages.
|
||
</para>
|
||
<para>
|
||
For successful call graph analysis the binaries must preserve the frame
|
||
pointer register and should also be compiled with the
|
||
"-fno-omit-framepointer" flag.
|
||
In Poky you can achieve this by setting
|
||
<glossterm><link linkend='var-SELECTED_OPTIMIZATION'>SELECTED_OPTIMIZATION
|
||
</link></glossterm> to "-fexpensive-optimizations -fno-omit-framepointer
|
||
-frename-registers -O2".
|
||
You can also achieve it by setting
|
||
<glossterm><link linkend='var-DEBUG_BUILD'>DEBUG_BUILD</link></glossterm> to "1" in
|
||
<filename>local.conf</filename>.
|
||
If you use the DEBUG_BUILD variable you will also add extra debug information
|
||
that can make the debug packages large.
|
||
</para>
|
||
|
||
<section id="platdev-oprofile-target">
|
||
<title>Profiling on the Target</title>
|
||
|
||
<para>
|
||
Using OProfile you can perform all the profiling work on the target device.
|
||
A simple OProfile session might look like the following:
|
||
</para>
|
||
|
||
<para>
|
||
<literallayout class='monospaced'>
|
||
# opcontrol --reset
|
||
# opcontrol --start --separate=lib --no-vmlinux -c 5
|
||
[do whatever is being profiled]
|
||
# opcontrol --stop
|
||
$ opreport -cl
|
||
</literallayout>
|
||
</para>
|
||
|
||
<para>
|
||
In this example, the reset command clears any previously profiled data.
|
||
The next command starts OProfile.
|
||
The options used when starting the profiler separate dynamic library data
|
||
within applications, disable kernel profiling, and enable callgraphing up to
|
||
five levels deep.
|
||
</para>
|
||
<note><para>
|
||
To profile the kernel, you would specify the
|
||
<parameter>--vmlinux=/path/to/vmlinux</parameter> option.
|
||
The vmlinux file is usually in <filename class="directory">/boot/</filename>
|
||
in Poky and must match the running kernel.
|
||
</para></note>
|
||
<para>
|
||
After you perform your profiling tasks, the next command stops the profiler.
|
||
After that you can view results with the "opreport" command with options
|
||
to see the separate library symbols and callgraph information.
|
||
</para>
|
||
<para>
|
||
Callgraphing logs information about time spent in functions and about a function's
|
||
calling function (parent) and called functions (children).
|
||
The higher the callgraphing depth,
|
||
the more accurate the results.
|
||
However, higher depths also increase the logging
|
||
overhead.
|
||
Consequently, you should take care when setting the callgraphing depth.
|
||
</para>
|
||
<note><para>
|
||
On ARM, binaries need to have the frame pointer enabled for callgraphing to work.
|
||
To accomplish this use the <filename>-fno-omit-framepointer</filename> option
|
||
with <filename>gcc</filename>.
|
||
</para></note>
|
||
<para>
|
||
For more information on using OProfile, see the OProfile
|
||
online documentation at
|
||
<ulink url="http://oprofile.sourceforge.net/docs/"/>.
|
||
</para>
|
||
</section>
|
||
|
||
<section id="platdev-oprofile-oprofileui">
|
||
<title>Using OProfileUI</title>
|
||
|
||
<para>
|
||
A graphical user interface for OProfile is also available.
|
||
You can download and build it from the Yocto Project at
|
||
<ulink url="http://git.yoctoproject.org/cgit.cgi/oprofileui/"></ulink>.
|
||
If the "tools-profile" image feature is selected, all necessary binaries
|
||
are installed onto the target device for OProfileUI interaction.
|
||
</para>
|
||
|
||
<!-- DISABLED, Need a more 'contextual' shot?
|
||
<screenshot>
|
||
<mediaobject>
|
||
<imageobject>
|
||
<imagedata fileref="screenshots/ss-oprofile-viewer.png" format="PNG"/>
|
||
</imageobject>
|
||
<caption>
|
||
<para>OProfileUI Viewer showing an application being profiled on a remote device</para>
|
||
</caption>
|
||
</mediaobject>
|
||
</screenshot>
|
||
|
||
<para>
|
||
In order to convert the data in the sample format from the target
|
||
to the host you need the <filename>opimport</filename> program.
|
||
This program is not included in standard Debian OProfile packages.
|
||
However, an OProfile package with this addition is available from the
|
||
<ulink url='http://debian.o-hand.com/'>OpenedHand repository</ulink>.
|
||
We recommend using OProfile 0.9.3 or greater.
|
||
</para>
|
||
-->
|
||
<para>
|
||
Even though Poky usually includes all needed patches on the target device, you
|
||
might find you need other OProfile patches for recent OProfileUI features.
|
||
If so, see the <ulink url='http://git.yoctoproject.org/cgit.cgi/oprofileui/tree/README'>
|
||
OProfileUI README</ulink> for the most recent information.
|
||
</para>
|
||
|
||
<section id="platdev-oprofile-oprofileui-online">
|
||
<title>Online Mode</title>
|
||
|
||
<para>
|
||
Using OProfile in online mode assumes a working network connection with the target
|
||
hardware.
|
||
With this connection, you just need to run "oprofile-server" on the device.
|
||
By default OProfile listens on port 4224.
|
||
</para>
|
||
<note><para>
|
||
You can change the port using the <filename>--port</filename> command-line
|
||
option.
|
||
</para></note>
|
||
|
||
<para>
|
||
The client program is called "oprofile-viewer" and its UI is relatively
|
||
straightforward.
|
||
You access key functionality through the buttons on the toolbar, which
|
||
are duplicated in the menus.
|
||
The buttons are:
|
||
</para>
|
||
|
||
<itemizedlist>
|
||
<listitem>
|
||
<para>
|
||
Connect - Connects to the remote host.
|
||
You can also supply the IP address or hostname.
|
||
</para>
|
||
</listitem>
|
||
<listitem>
|
||
<para>
|
||
Disconnect - Disconnects from the target.
|
||
</para>
|
||
</listitem>
|
||
<listitem>
|
||
<para>
|
||
Start - Starts profiling on the device.
|
||
</para>
|
||
</listitem>
|
||
<listitem>
|
||
<para>
|
||
Stop - Stops profiling on the device and downloads the data to the local
|
||
host.
|
||
Stopping the profiler generates the profile and displays it in the viewer.
|
||
</para>
|
||
</listitem>
|
||
<listitem>
|
||
<para>
|
||
Download - Downloads the data from the target and generates the profile,
|
||
which appears in the viewer.
|
||
</para>
|
||
</listitem>
|
||
<listitem>
|
||
<para>
|
||
Reset - Resets the sample data on the device.
|
||
Resetting the data removes sample information collected from previous
|
||
sampling runs.
|
||
Be sure you reset the data if you do not want to include old sample information.
|
||
</para>
|
||
</listitem>
|
||
<listitem>
|
||
<para>
|
||
Save - Saves the data downloaded from the target to another directory for later
|
||
examination.
|
||
</para>
|
||
</listitem>
|
||
<listitem>
|
||
<para>
|
||
Open - Loads previously saved data.
|
||
</para>
|
||
</listitem>
|
||
</itemizedlist>
|
||
|
||
<para>
|
||
The client downloads the complete 'profile archive' from
|
||
the target to the host for processing.
|
||
This archive is a directory that contains the sample data, the object files
|
||
and the debug information for the object files.
|
||
The archive is then converted using the "oparchconv" script, which is
|
||
included in this distribution.
|
||
The script uses "opimport" to convert the archive from
|
||
the target to something that can be processed on the host.
|
||
</para>
|
||
|
||
<para>
|
||
Downloaded archives reside in <filename>/tmp</filename> and are cleared up
|
||
when they are no longer in use.
|
||
</para>
|
||
|
||
<para>
|
||
If you wish to perform kernel profiling you need to be sure
|
||
a "vmlinux" file that matches the running kernel is available.
|
||
In Poky, that file is usually located in
|
||
<filename>/boot/vmlinux-KERNELVERSION</filename>, where KERNEL-version is the
|
||
version of the kernel.
|
||
Poky generates separate vmlinux packages for each kernel
|
||
it builds so it should be a question of just making sure a matching package is
|
||
installed - for example: <filename>opkg install kernel-vmlinux</filename>.
|
||
The files are automatically installed into development and profiling images
|
||
alongside OProfile.
|
||
There is a configuration option within the OProfileUI settings page where
|
||
you can enter the location of the vmlinux file.
|
||
</para>
|
||
|
||
<para>
|
||
Waiting for debug symbols to transfer from the device can be slow, and it
|
||
is not always necessary to actually have them on the device for OProfile use.
|
||
All that is needed is a copy of the filesystem with the debug symbols present
|
||
on the viewer system.
|
||
The "<link linkend='platdev-gdb-remotedebug-launch-gdb'>Launching GDB
|
||
on the Host Computer</link>" section covers how to create such a directory with Poky and
|
||
how to use the OProfileUI Settings dialog to specify the location.
|
||
If you specify the directory, it will be used when the file checksums
|
||
match those on the system you are profiling.
|
||
</para>
|
||
</section>
|
||
|
||
<section id="platdev-oprofile-oprofileui-offline">
|
||
<title>Offline Mode</title>
|
||
|
||
<para>
|
||
If network access to the target is unavailable, you can generate
|
||
an archive for processing in "oprofile-viewer" as follows:
|
||
</para>
|
||
|
||
<para>
|
||
<literallayout class='monospaced'>
|
||
# opcontrol --reset
|
||
# opcontrol --start --separate=lib --no-vmlinux -c 5
|
||
[do whatever is being profiled]
|
||
# opcontrol --stop
|
||
# oparchive -o my_archive
|
||
</literallayout>
|
||
</para>
|
||
|
||
<para>
|
||
In the above example <filename>my_archive</filename> is the name of the
|
||
archive directory where you would like the profile archive to be kept.
|
||
After the directory is created, you can copy it to another host and load it
|
||
using "oprofile-viewer" open functionality.
|
||
If necessary, the archive is converted.
|
||
</para>
|
||
</section>
|
||
</section>
|
||
</section>
|
||
|
||
|
||
|
||
</chapter>
|
||
<!--
|
||
vim: expandtab tw=80 ts=4
|
||
-->
|