857 lines
42 KiB
XML
857 lines
42 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. These different
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forms of development are explained below and can be switched
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between as needed.
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</para>
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<section id="platdev-appdev-external-sdk">
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<title>Developing externally using the Poky SDK</title>
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<para>
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The meta-toolchain and meta-toolchain-sdk targets (<link linkend='ref-images'>see
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the images section</link>) build tarballs which contain toolchains and
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libraries suitable for application development outside Poky. These 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> which
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can be sourced to initialise a suitable environment. After sourcing this, the
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compiler, QEMU scripts, QEMU binary, a special version of pkgconfig and other
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useful utilities are added to the PATH. Variables to assist pkgconfig and
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autotools are also set so that, for example, configure can find pre-generated test
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results for tests which need target hardware 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 e.g. "./configure --host=arm-poky-linux-gnueabi".
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For other projects it is usually a case of ensuring the cross tools are used e.g.
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CC=arm-poky-linux-gnueabi-gcc and LD=arm-poky-linux-gnueabi-ld.
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</para>
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</section>
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<section id="platdev-appdev-external-anjuta">
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<title>Developing externally using the Anjuta plugin</title>
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<para>
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An Anjuta IDE plugin exists to make developing software within the Poky framework
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easier for the application developer. It presents a graphical IDE from which the
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developer can cross compile an application then deploy and execute the output in a QEMU
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emulation session. It also supports cross debugging and profiling.
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</para>
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<!-- DISBALED, TOO BIG!
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<screenshot>
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<mediaobject>
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<imageobject>
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<imagedata fileref="screenshots/ss-anjuta-poky-1.png" format="PNG"/>
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</imageobject>
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<caption>
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<para>The Anjuta Poky SDK plugin showing an active QEMU session running Sato</para>
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</caption>
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</mediaobject>
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</screenshot>
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-->
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<para>
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To use the plugin, a toolchain and SDK built by Poky is required along with Anjuta it's development
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headers and the Anjuta plugin. The Poky Anjuta plugin is available to download as a tarball at the
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<ulink url='http://labs.o-hand.com/sources/anjuta-plugin-sdk/'>OpenedHand labs</ulink> page or
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directly from the Poky Git repository located at git://git.pokylinux.org/anjuta-poky; a web interface
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to the repository can be accessed at <ulink url='http://git.pokylinux.org/cgit.cgi/anjuta-poky/'/>.
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</para>
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<para>
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See the README file contained in the project for more information on dependencies and building
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the plugin. It's recommended you enable the experimental gdb integration by passing configure the
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--enable-gdb-integration switch.
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</para>
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<section id="platdev-appdev-external-anjuta-setup">
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<title>Setting up the Anjuta plugin</title>
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<para>Extract the tarball for the toolchain into / as root. The
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toolchain will be installed into
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<filename class="directory">/opt/poky</filename>.</para>
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<para>To use the plugin, first open or create an existing
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project. If creating a new project the "C GTK+" project type
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will allow itself to be cross-compiled. However you should be
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aware that this uses glade for the UI.</para>
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<para>To activate the plugin go to
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<menuchoice><guimenu>Edit</guimenu><guimenuitem>Preferences</guimenuitem></menuchoice>,
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then choose <guilabel>General</guilabel> from the left hand side. Choose the
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Installed plugins tab, scroll down to <guilabel>Poky
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SDK</guilabel> and check the
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box. The plugin is now activated but first it must be
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configured.</para>
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</section>
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<section id="platdev-appdev-external-anjuta-configuration">
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<title>Configuring the Anjuta plugin</title>
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<para>The configuration options for the SDK can be found by choosing
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the <guilabel>Poky SDK</guilabel> icon from the left hand side. The following options
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need to be set:</para>
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<itemizedlist>
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<listitem><para><guilabel>SDK root</guilabel>: this is the root directory of the SDK's sysroot
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for an i586 SDK this will be <filename
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class="directory">/opt/poky/sysroots/i586-poky-linux</filename>.
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This directory will contain directories named like "bin",
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"include", "var", etc. With the file chooser it is important
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to enter into the "i586-poky-linux" subdirectory for this
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example.</para></listitem>
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<listitem><para><guilabel>Toolchain triplet</guilabel>: this is the cross compile
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triplet, e.g. "i586-poky-linux".</para></listitem>
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<listitem><para><guilabel>Kernel</guilabel>: use the file chooser to select the kernel
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to use with QEMU</para></listitem>
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<listitem><para><guilabel>Root filesystem</guilabel>: use the file chooser to select
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the root filesystem image, this should be an image (not a
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tarball)</para></listitem>
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</itemizedlist>
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<!-- DISBALED, TOO BIG!
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<screenshot>
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<mediaobject>
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<imageobject>
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<imagedata fileref="screenshots/ss-anjuta-poky-2.png" format="PNG"/>
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</imageobject>
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<caption>
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<para>Anjuta Preferences Dialog</para>
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</caption>
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</mediaobject>
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</screenshot>
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-->
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</section>
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<section id="platdev-appdev-external-anjuta-usage">
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<title>Using the Anjuta plugin</title>
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<para>As an example, cross-compiling a project, deploying it into
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QEMU and running a debugger against it and then doing a system
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wide profile.</para>
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<para>Choose <menuchoice><guimenu>Build</guimenu><guimenuitem>Run
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Configure</guimenuitem></menuchoice> or
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<menuchoice><guimenu>Build</guimenu><guimenuitem>Run
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Autogenerate</guimenuitem></menuchoice> to run "configure"
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(or to run "autogen") for the project. This passes command line
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arguments to instruct it to cross-compile.</para>
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<para>Next do
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<menuchoice><guimenu>Build</guimenu><guimenuitem>Build
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Project</guimenuitem></menuchoice> to build and compile the
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project. If you have previously built the project in the same
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tree without using the cross-compiler you may find that your
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project fails to link. Simply do
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<menuchoice><guimenu>Build</guimenu><guimenuitem>Clean
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Project</guimenuitem></menuchoice> to remove the old
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binaries. You may then try building again.</para>
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<para>Next start QEMU by using
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<menuchoice><guimenu>Tools</guimenu><guimenuitem>Start
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QEMU</guimenuitem></menuchoice>, this will start QEMU and
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will show any error messages in the message view. Once Poky has
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fully booted within QEMU you may now deploy into it.</para>
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<para>Once built and QEMU is running, choose
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<menuchoice><guimenu>Tools</guimenu><guimenuitem>Deploy</guimenuitem></menuchoice>,
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this will install the package into a temporary directory and
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then copy using rsync over SSH into the target. Progress and
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messages will be shown in the message view.</para>
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<para>To debug a program installed into onto the target choose
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<menuchoice><guimenu>Tools</guimenu><guimenuitem>Debug
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remote</guimenuitem></menuchoice>. This prompts for the
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local binary to debug and also the command line to run on the
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target. The command line to run should include the full path to
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the to binary installed in the target. This will start a
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gdbserver over SSH on the target and also an instance of a
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cross-gdb in a local terminal. This will be preloaded to connect
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to the server and use the <guilabel>SDK root</guilabel> to find
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symbols. This gdb will connect to the target and load in
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various libraries and the target program. You should setup any
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breakpoints or watchpoints now since you might not be able to
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interrupt the execution later. You may stop
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the debugger on the target using
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<menuchoice><guimenu>Tools</guimenu><guimenuitem>Stop
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debugger</guimenuitem></menuchoice>.</para>
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<para>It is also possible to execute a command in the target over
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SSH, the appropriate environment will be be set for the
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execution. Choose
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<menuchoice><guimenu>Tools</guimenu><guimenuitem>Run
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remote</guimenuitem></menuchoice> to do this. This will open
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a terminal with the SSH command inside.</para>
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<para>To do a system wide profile against the system running in
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QEMU choose
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<menuchoice><guimenu>Tools</guimenu><guimenuitem>Profile
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remote</guimenuitem></menuchoice>. This will start up
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OProfileUI with the appropriate parameters to connect to the
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server running inside QEMU and will also supply the path to the
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debug information necessary to get a useful profile.</para>
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</section>
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</section>
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<section id="platdev-appdev-qemu">
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<title>Developing externally in QEMU</title>
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<para>
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Running Poky QEMU images is covered in the <link
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linkend='intro-quickstart-qemu'>Running an Image</link> section.
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</para>
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<para>
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Poky's QEMU images contain a complete native toolchain. This means
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that applications can be developed within QEMU in the same was as a
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normal system. Using qemux86 on an x86 machine is fast since the
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guest and host architectures match, qemuarm is slower but gives
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faithful emulation of ARM specific issues. To speed things up these
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images support using distcc to call a cross-compiler outside the
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emulated system too. If <command>runqemu</command> was used to start
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QEMU, and distccd is present on the host system, any bitbake cross
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compiling toolchain available from the build system will automatically
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be used from within qemu simply by calling distcc
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(<command>export CC="distcc"</command> can be set in the enviroment).
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Alterntatively, if a suitable SDK/toolchain is present in
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<filename class="directory">/opt/poky</filename> it will also
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automatically be used.
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</para>
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<para>
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There are several options for connecting into the emulated system.
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QEMU provides a framebuffer interface which has standard consoles
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available. There is also a serial connection available which has a
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console to the system running on it and IP networking as standard.
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The images have a dropbear ssh server running with the root password
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disabled allowing standard ssh and scp commands to work. The images
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also contain an NFS server exporting the guest's root filesystem
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allowing that to be made available to the host.
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</para>
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</section>
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<section id="platdev-appdev-chroot">
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<title>Developing externally in a chroot</title>
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<para>
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If you have a system that matches the architecture of the Poky machine you're using,
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such as qemux86, you can run binaries directly from the image on the host system
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using a chroot combined with tools like <ulink url='http://projects.o-hand.com/xephyr'>Xephyr</ulink>.
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</para>
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<para>
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Poky has some scripts to make using its qemux86 images within a chroot easier. To use
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these you need to install the poky-scripts package or otherwise obtain the
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<filename>poky-chroot-setup</filename> and <filename>poky-chroot-run</filename> scripts.
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You also need Xephyr and chrootuid binaries available. To initialize a system use the setup script:
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</para>
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<para>
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<literallayout class='monospaced'>
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# poky-chroot-setup <qemux86-rootfs.tgz> <target-directory>
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</literallayout>
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</para>
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<para>
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which will unpack the specified qemux86 rootfs tarball into the target-directory.
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You can then start the system with:
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</para>
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<para>
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<literallayout class='monospaced'>
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# poky-chroot-run <target-directory> <command>
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</literallayout>
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</para>
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<para>
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where the target-directory is the place the rootfs was unpacked to and command is
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an optional command to run. If no command is specified, the system will drop you
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within a bash shell. A Xephyr window will be displayed containing the emulated
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system and you may be asked for a password since some of the commands used for
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bind mounting directories need to be run using sudo.
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</para>
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<para>
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There are limits as to how far the the realism of the chroot environment extends.
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It is useful for simple development work or quick tests but full system emulation
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with QEMU offers a much more realistic environment for more complex development
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tasks. Note that chroot support within Poky is still experimental.
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</para>
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</section>
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<section id="platdev-appdev-insitu">
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<title>Developing in Poky directly</title>
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<para>
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Working directly in Poky is a fast and effective development technique.
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The idea is that you can directly edit files in
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<glossterm><link linkend='var-WORKDIR'>WORKDIR</link></glossterm>
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or the source directory <glossterm><link linkend='var-S'>S</link></glossterm>
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and then force specific tasks to rerun in order to test the changes.
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An example session working on the matchbox-desktop package might
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look like this:
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</para>
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<para>
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<literallayout class='monospaced'>
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$ bitbake matchbox-desktop
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$ sh
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$ cd tmp/work/armv5te-poky-linux-gnueabi/matchbox-desktop-2.0+svnr1708-r0/
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$ cd matchbox-desktop-2
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$ vi src/main.c
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$ exit
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$ bitbake matchbox-desktop -c compile -f
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$ bitbake matchbox-desktop
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</literallayout>
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</para>
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<para>
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Here, we build the package, change into the work directory for the package,
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change a file, then recompile the package. Instead of using sh like this,
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you can also use two different terminals. The risk with working like this
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is that a command like unpack could wipe out the changes you've made to the
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work directory so you need to work carefully.
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</para>
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<para>
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It is useful when making changes directly to the work directory files to do
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so using quilt as detailed in the <link linkend='usingpoky-modifying-packages-quilt'>
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modifying packages with quilt</link> section. The resulting patches can be copied
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into the recipe directory and used directly in the <glossterm><link
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linkend='var-SRC_URI'>SRC_URI</link></glossterm>.
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</para>
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<para>
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For a review of the skills used in this section see Sections <link
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linkend="usingpoky-components-bitbake">2.1.1</link> and <link
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linkend="usingpoky-debugging-taskrunning">2.4.2</link>.
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</para>
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</section>
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<section id="platdev-appdev-devshell">
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<title>Developing with 'devshell'</title>
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<para>
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When debugging certain commands or even to just edit packages, the
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'devshell' can be a useful tool. To start it you run a command like:
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</para>
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<para>
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<literallayout class='monospaced'>
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$ bitbake matchbox-desktop -c devshell
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</literallayout>
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</para>
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<para>
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which will open a terminal with a shell prompt within the Poky
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environment. This means PATH is setup to include the cross toolchain,
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the pkgconfig variables are setup to find the right .pc files,
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configure will be able to find the Poky site files etc. Within this
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environment, you can run configure or compile command as if they
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were being run by Poky itself. You are also changed into the
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source (<glossterm><link linkend='var-S'>S</link></glossterm>)
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directory automatically. When finished with the shell just exit it
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or close the terminal window.
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</para>
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<para>
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The default shell used by devshell is the gnome-terminal. Other
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forms of terminal can also be used by setting the <glossterm>
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<link linkend='var-TERMCMD'>TERMCMD</link></glossterm> and <glossterm>
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<link linkend='var-TERMCMDRUN'>TERMCMDRUN</link></glossterm> variables
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in local.conf. For examples of the other options available, see
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<filename>meta/conf/bitbake.conf</filename>. An external shell is
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launched rather than opening directly into the original terminal
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window to make interaction with bitbakes multiple threads easier
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and also allow a client/server split of bitbake in the future
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(devshell will still work over X11 forwarding or similar).
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</para>
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<para>
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It is worth remembering that inside devshell you need to use the full
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compiler name such as <command>arm-poky-linux-gnueabi-gcc</command>
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instead of just <command>gcc</command> and the same applies to other
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applications from gcc, bintuils, libtool etc. Poky will have setup
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environmental variables such as CC to assist applications, such as make,
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find the correct tools.
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</para>
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</section>
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<section id="platdev-appdev-srcrev">
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<title>Developing within Poky with an external SCM based package</title>
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<para>
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If you're working on a recipe which pulls from an external SCM it
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is possible to have Poky notice new changes added to the
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SCM and then build the latest version. This only works for SCMs
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where its possible to get a sensible revision number for changes.
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Currently it works for svn, git and bzr repositories.
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</para>
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<para>
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To enable this behaviour it is simply a case of adding <glossterm>
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<link linkend='var-SRCREV'>SRCREV</link></glossterm>_pn-<glossterm>
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<link linkend='var-PN'>PN</link></glossterm> = "${AUTOREV}" to
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local.conf where <glossterm><link linkend='var-PN'>PN</link></glossterm>
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is the name of the package for which you want to enable automatic source
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revision updating.
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</para>
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</section>
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</section>
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<section id="platdev-gdb-remotedebug">
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<title>Debugging with GDB Remotely</title>
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<para>
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<ulink url="http://sourceware.org/gdb/">GDB</ulink> (The GNU Project Debugger)
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allows you to examine running programs to understand and fix problems and
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also to perform postmortem style analsys of program crashes. It is available
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as a package within poky and installed by default in sdk images. It works best
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when -dbg packages for the application being debugged are installed as the
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extra symbols give more meaningful output from GDB.
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</para>
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<para>
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Sometimes, due to memory or disk space constraints, it is not possible
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to use GDB directly on the remote target to debug applications. This is
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due to the fact that
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GDB needs to load the debugging information and the binaries of the
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process being debugged. GDB then needs to perform many
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computations to locate information such as function names, variable
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names and values, stack traces, etc. even before starting the debugging
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process. This places load on the target system and can alter the
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characteristics of the program being debugged.
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</para>
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<para>
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This is where GDBSERVER comes into play as it runs on the remote target
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and does not load any debugging information from the debugged process.
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Instead, the debugging information processing is done by a GDB instance
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running on a distant computer - the host GDB. The host GDB then sends
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control commands to GDBSERVER to make it stop or start the debugged
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program, as well as read or write some memory regions of that debugged
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program. All the debugging information loading and processing as well
|
|
as the heavy debugging duty is done by the host GDB, giving the
|
|
GDBSERVER running on the target a chance to remain small and fast.
|
|
</para>
|
|
<para>
|
|
As the host GDB is responsible for loading the debugging information and
|
|
doing the necessary processing to make actual debugging happen, the
|
|
user has to make sure it can access the unstripped binaries complete
|
|
with their debugging information and compiled with no optimisations. The
|
|
host GDB must also have local access to all the libraries used by the
|
|
debugged program. On the remote target the binaries can remain stripped
|
|
as GDBSERVER does not need any debugging information there. However they
|
|
must also be compiled without optimisation matching the host's binaries.
|
|
</para>
|
|
|
|
<para>
|
|
The binary being debugged on the remote target machine is hence referred
|
|
to as the 'inferior' in keeping with GDB documentation and terminology.
|
|
Further documentation on GDB, is available on
|
|
<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 gdbserver package (which needs the libthread-db1
|
|
package).
|
|
</para>
|
|
<para>
|
|
To launch GDBSERVER on the target and make it ready to "debug" a
|
|
program located at <emphasis>/path/to/inferior</emphasis>, connect
|
|
to the target and launch:
|
|
<programlisting>$ gdbserver localhost:2345 /path/to/inferior</programlisting>
|
|
After that, gdbserver should be listening on port 2345 for debugging
|
|
commands coming from a remote GDB process running on the host computer.
|
|
Communication between the GDBSERVER and the host GDB will be 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, described in the
|
|
following sections.
|
|
</para>
|
|
|
|
<section id="platdev-gdb-remotedebug-launch-gdb-buildcross">
|
|
<title>Build the cross GDB package</title>
|
|
<para>
|
|
A suitable gdb cross binary is required which runs on your host computer but
|
|
knows about the the ABI of the remote target. This can be obtained from
|
|
the the Poky toolchain, e.g.
|
|
<filename>/usr/local/poky/eabi-glibc/arm/bin/arm-poky-linux-gnueabi-gdb</filename>
|
|
which "arm" is the target architecture and "linux-gnueabi" the target ABI.
|
|
</para>
|
|
|
|
<para>
|
|
Alternatively this can be built directly by Poky. To do this you would build
|
|
the gdb-cross package so for example you would run:
|
|
<programlisting>bitbake gdb-cross</programlisting>
|
|
Once built, the cross gdb binary can be found at
|
|
<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 needs to be available to GDB complete with all debugging
|
|
symbols in order to get the best possible results along with any libraries
|
|
the inferior depends on and their debugging symbols. There are a number of
|
|
ways this can be done.
|
|
</para>
|
|
|
|
<para>
|
|
Perhaps the easiest is to have an 'sdk' image corresponding to the plain
|
|
image installed on the device. In the case of 'pky-image-sato',
|
|
'poky-image-sdk' would contain suitable symbols. The sdk images already
|
|
have the debugging symbols installed so its just a question expanding the
|
|
archive to some location and telling GDB where this is.
|
|
</para>
|
|
|
|
<para>
|
|
Alternatively, poky can build a custom directory of files for a specific
|
|
debugging purpose by reusing its tmp/rootfs directory, on the host computer
|
|
in a slightly different way to normal. This directory contains the contents
|
|
of the last built image. This process assumes the image running on the
|
|
target was the last image to be built by Poky, the package <emphasis>foo</emphasis>
|
|
contains the inferior binary to be debugged has been built without without
|
|
optimisation and has debugging information available.
|
|
</para>
|
|
<para>
|
|
Firstly you want to install the <emphasis>foo</emphasis> package to tmp/rootfs
|
|
by doing:
|
|
</para>
|
|
<programlisting>tmp/sysroots/i686-linux/usr/bin/opkg-cl -f \
|
|
tmp/work/<target-abi>/poky-image-sato-1.0-r0/temp/opkg.conf -o \
|
|
tmp/rootfs/ update</programlisting>
|
|
<para>
|
|
then,
|
|
</para>
|
|
<programlisting>tmp/sysroots/i686-linux/usr/bin/opkg-cl -f \
|
|
tmp/work/<target-abi>/poky-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>/poky-image-sato-1.0-r0/temp/opkg.conf \
|
|
-o tmp/rootfs install foo-dbg</programlisting>
|
|
<para>
|
|
which installs the debugging information too.
|
|
</para>
|
|
|
|
</section>
|
|
<section id="platdev-gdb-remotedebug-launch-gdb-launchhost">
|
|
|
|
<title>Launch the host GDB</title>
|
|
<para>
|
|
To launch the host GDB, run the cross gdb binary identified above with
|
|
the inferior binary specified on the commandline:
|
|
<programlisting><target-abi>-gdb rootfs/usr/bin/foo</programlisting>
|
|
This loads the binary of program <emphasis>foo</emphasis>
|
|
as well as its debugging information. Once the gdb prompt
|
|
appears, you must instruct GDB to load all the libraries
|
|
of the inferior from tmp/rootfs:
|
|
<programlisting>set solib-absolute-prefix /path/to/tmp/rootfs</programlisting>
|
|
where <filename>/path/to/tmp/rootfs</filename> must be
|
|
the absolute path to <filename>tmp/rootfs</filename> or wherever the
|
|
binaries with debugging information are located.
|
|
</para>
|
|
<para>
|
|
Now, tell GDB to connect to the GDBSERVER running on the remote target:
|
|
<programlisting>target remote remote-target-ip-address:2345</programlisting>
|
|
Where remote-target-ip-address is the IP address of the
|
|
remote target where the GDBSERVER is running. 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>
|
|
Debugging can now proceed as normal, as if the debugging were being done on the
|
|
local machine, for example to tell GDB to break in the <emphasis>main</emphasis>
|
|
function, for instance:
|
|
<programlisting>break main</programlisting>
|
|
and then to tell GDB to "continue" the inferior execution,
|
|
<programlisting>continue</programlisting>
|
|
</para>
|
|
<para>
|
|
For more information about using GDB please 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 to finding performance
|
|
bottlenecks in both userspace software and the kernel. It provides
|
|
answers to questions like "Which functions does my application spend
|
|
the most time in when doing X?". Poky is well integrated with OProfile
|
|
to make profiling applications on target hardware straightforward.
|
|
</para>
|
|
|
|
<para>
|
|
To use OProfile you need an image with 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
|
|
will take place. This can be achieved with "dbg-pkgs" in <glossterm><link
|
|
linkend='var-IMAGE_FEATURES'>IMAGE_FEATURES</link></glossterm> or by
|
|
installing the appropriate -dbg packages. For
|
|
successful call graph analysis the binaries must preserve the frame
|
|
pointer register and hence should be compiled with the
|
|
"-fno-omit-framepointer" flag. In Poky this can be achieved with
|
|
<glossterm><link linkend='var-SELECTED_OPTIMIZATION'>SELECTED_OPTIMIZATION
|
|
</link></glossterm> = "-fexpensive-optimizations -fno-omit-framepointer
|
|
-frename-registers -O2" or by setting <glossterm><link
|
|
linkend='var-DEBUG_BUILD'>DEBUG_BUILD</link></glossterm> = "1" in
|
|
local.conf (the latter will also add extra debug information making the
|
|
debug packages large).
|
|
</para>
|
|
|
|
<section id="platdev-oprofile-target">
|
|
<title>Profiling on the target</title>
|
|
|
|
<para>
|
|
All the profiling work can be performed on the target device. A
|
|
simple OProfile session might look like:
|
|
</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>
|
|
Here, the reset command clears any previously profiled data,
|
|
OProfile is then started. The options used to start OProfile mean
|
|
dynamic library data is kept separately per application, kernel
|
|
profiling is disabled and callgraphing is enabled up to 5 levels
|
|
deep. 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). The profile is
|
|
then stopped and the results viewed with opreport with options
|
|
to see the separate library symbols and callgraph information.
|
|
</para>
|
|
<para>
|
|
Callgraphing means OProfile not only logs infomation about which
|
|
functions time is being spent in but also which functions
|
|
called those functions (their parents) and which functions that
|
|
function calls (its children). The higher the callgraphing depth,
|
|
the more accurate the results but this also increased the loging
|
|
overhead so it should be used with caution. On ARM, binaries need
|
|
to have the frame pointer enabled for callgraphing to work (compile
|
|
with the gcc option -fno-omit-framepointer).
|
|
</para>
|
|
<para>
|
|
For more information on using OProfile please 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
|
|
either use prebuilt Debian packages from the <ulink
|
|
url='http://debian.o-hand.com/'>OpenedHand repository</ulink> or
|
|
download and build from svn at
|
|
http://svn.o-hand.com/repos/oprofileui/trunk/. If the
|
|
"tools-profile" image feature is selected, all necessary binaries
|
|
are installed onto the target device for OProfileUI interaction.
|
|
</para>
|
|
|
|
<!-- DISBALED, Need a more 'contexual' 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 the <filename>opimport</filename> program is needed.
|
|
This is not included in standard Debian OProfile packages but an
|
|
OProfile package with this addition is also available from the <ulink
|
|
url='http://debian.o-hand.com/'>OpenedHand repository</ulink>.
|
|
We recommend using OProfile 0.9.3 or greater. Other patches to
|
|
OProfile may be needed for recent OProfileUI features, but Poky
|
|
usually includes all needed patches on the target device. Please
|
|
see the <ulink
|
|
url='http://svn.o-hand.com/repos/oprofileui/trunk/README'>
|
|
OProfileUI README</ulink> for up to date information, and the
|
|
<ulink url="http://labs.o-hand.com/oprofileui">OProfileUI website
|
|
</ulink> for more information on the OProfileUI project.
|
|
</para>
|
|
|
|
<section id="platdev-oprofile-oprofileui-online">
|
|
<title>Online mode</title>
|
|
|
|
<para>
|
|
This assumes a working network connection with the target
|
|
hardware. In this case you just need to run <command>
|
|
"oprofile-server"</command> on the device. By default it listens
|
|
on port 4224. This can be changed with the <parameter>--port</parameter> command line
|
|
option.
|
|
|
|
</para>
|
|
|
|
<para>
|
|
The client program is called <command>oprofile-viewer</command>. The
|
|
UI is relatively straightforward, the key functionality is accessed
|
|
through the buttons on the toolbar (which are duplicated in the
|
|
menus.) These buttons are:
|
|
</para>
|
|
|
|
<itemizedlist>
|
|
<listitem>
|
|
<para>
|
|
Connect - connect to the remote host, the IP address or hostname for the
|
|
target can be supplied here.
|
|
</para>
|
|
</listitem>
|
|
<listitem>
|
|
<para>
|
|
Disconnect - disconnect from the target.
|
|
</para>
|
|
</listitem>
|
|
<listitem>
|
|
<para>
|
|
Start - start the profiling on the device.
|
|
</para>
|
|
</listitem>
|
|
<listitem>
|
|
<para>
|
|
Stop - stop the profiling on the device and download the data to the local
|
|
host. This will generate the profile and show it in the viewer.
|
|
</para>
|
|
</listitem>
|
|
<listitem>
|
|
<para>
|
|
Download - download the data from the target, generate the profile and show it
|
|
in the viewer.
|
|
</para>
|
|
</listitem>
|
|
<listitem>
|
|
<para>
|
|
Reset - reset the sample data on the device. This will remove the sample
|
|
information that was collected on a previous sampling run. Ensure you do this
|
|
if you do not want to include old sample information.
|
|
</para>
|
|
</listitem>
|
|
<listitem>
|
|
<para>
|
|
Save - save the data downloaded from the target to another directory for later
|
|
examination.
|
|
</para>
|
|
</listitem>
|
|
<listitem>
|
|
<para>
|
|
Open - load data that was previously saved.
|
|
</para>
|
|
</listitem>
|
|
</itemizedlist>
|
|
|
|
<para>
|
|
The behaviour of the client is to download the complete 'profile archive' from
|
|
the target to the host for processing. This archive is a directory containing
|
|
the sample data, the object files and the debug information for said object
|
|
files. This archive is then converted using a script included in this
|
|
distribution ('oparchconv') that uses 'opimport' to convert the archive from
|
|
the target to something that can be processed on the host.
|
|
</para>
|
|
|
|
<para>
|
|
Downloaded archives are kept in /tmp and cleared up when they are no longer in
|
|
use.
|
|
</para>
|
|
|
|
<para>
|
|
If you wish to profile into the kernel, this is possible, you just need to ensure
|
|
a vmlinux file matching the running kernel is available. In Poky this is usually
|
|
located in /boot/vmlinux-KERNELVERSION, where KERNEL-version is the version of
|
|
the kernel e.g. 2.6.23. Poky generates separate vmlinux packages for each kernel
|
|
it builds so it should be a question of just ensuring a matching package is
|
|
installed (<command> opkg install kernel-vmlinux</command>. These are automatically
|
|
installed into development and profiling images alongside OProfile. There is a
|
|
configuration option within the OProfileUI settings page where the location of
|
|
the vmlinux file can be entered.
|
|
</para>
|
|
|
|
<para>
|
|
Waiting for debug symbols to transfer from the device can be slow and it's not
|
|
always necessary to actually have them on 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'>GDB remote debug
|
|
section</link> covers how to create such a directory with Poky and the location
|
|
of this directory can again be specified in the OProfileUI settings dialog. If
|
|
specified, it will be used where the file checksums match those on the system
|
|
being profiled.
|
|
</para>
|
|
</section>
|
|
<section id="platdev-oprofile-oprofileui-offline">
|
|
<title>Offline mode</title>
|
|
|
|
<para>
|
|
If no network access to the target is available an archive for processing in
|
|
'oprofile-viewer' can be generated with the following set of command.
|
|
</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>
|
|
Where my_archive is the name of the archive directory where you would like the
|
|
profile archive to be kept. The directory will be created for you. This can
|
|
then be copied to another host and loaded using 'oprofile-viewer''s open
|
|
functionality. The archive will be converted if necessary.
|
|
</para>
|
|
</section>
|
|
</section>
|
|
</section>
|
|
|
|
</chapter>
|
|
<!--
|
|
vim: expandtab tw=80 ts=4
|
|
-->
|