diff options
author | Richard Purdie <rpurdie@linux.intel.com> | 2010-10-15 11:55:59 +0100 |
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committer | Richard Purdie <rpurdie@linux.intel.com> | 2010-10-15 11:55:59 +0100 |
commit | 22083287912ebd552e33b79f7c567bc966376d43 (patch) | |
tree | a16fa012a97a249e25a405d4092b0a89321bfaf6 /documentation/poky-ref-manual/development.xml | |
parent | 13a702e9e572a2dc9f6b52a1531a2237d4d98ff1 (diff) | |
download | poky-22083287912ebd552e33b79f7c567bc966376d43.tar.gz |
handbook: Move into documentation directory
Signed-off-by: Richard Purdie <rpurdie@linux.intel.com>
Diffstat (limited to 'documentation/poky-ref-manual/development.xml')
-rw-r--r-- | documentation/poky-ref-manual/development.xml | 825 |
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1 | <!DOCTYPE chapter PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | ||
2 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | ||
3 | |||
4 | <chapter id="platdev"> | ||
5 | <title>Platform Development with Poky</title> | ||
6 | |||
7 | <section id="platdev-appdev"> | ||
8 | <title>Software development</title> | ||
9 | <para> | ||
10 | Poky supports several methods of software development. These different | ||
11 | forms of development are explained below and can be switched | ||
12 | between as needed. | ||
13 | </para> | ||
14 | |||
15 | <section id="platdev-appdev-external-sdk"> | ||
16 | <title>Developing externally using the Poky SDK</title> | ||
17 | |||
18 | <para> | ||
19 | The meta-toolchain and meta-toolchain-sdk targets (<link linkend='ref-images'>see | ||
20 | the images section</link>) build tarballs which contain toolchains and | ||
21 | libraries suitable for application development outside Poky. These unpack into the | ||
22 | <filename class="directory">/opt/poky</filename> directory and contain | ||
23 | a setup script, e.g. | ||
24 | <filename>/opt/poky/environment-setup-i586-poky-linux</filename> which | ||
25 | can be sourced to initialise a suitable environment. After sourcing this, the | ||
26 | compiler, QEMU scripts, QEMU binary, a special version of pkgconfig and other | ||
27 | useful utilities are added to the PATH. Variables to assist pkgconfig and | ||
28 | autotools are also set so that, for example, configure can find pre-generated test | ||
29 | results for tests which need target hardware to run. | ||
30 | </para> | ||
31 | |||
32 | <para> | ||
33 | Using the toolchain with autotool enabled packages is straightforward, just pass the | ||
34 | appropriate host option to configure e.g. "./configure --host=arm-poky-linux-gnueabi". | ||
35 | For other projects it is usually a case of ensuring the cross tools are used e.g. | ||
36 | CC=arm-poky-linux-gnueabi-gcc and LD=arm-poky-linux-gnueabi-ld. | ||
37 | </para> | ||
38 | </section> | ||
39 | |||
40 | <section id="platdev-appdev-external-anjuta"> | ||
41 | <title>Developing externally using the Anjuta plugin</title> | ||
42 | |||
43 | <para> | ||
44 | An Anjuta IDE plugin exists to make developing software within the Poky framework | ||
45 | easier for the application developer. It presents a graphical IDE from which the | ||
46 | developer can cross compile an application then deploy and execute the output in a QEMU | ||
47 | emulation session. It also supports cross debugging and profiling. | ||
48 | </para> | ||
49 | <!-- DISBALED, TOO BIG! | ||
50 | <screenshot> | ||
51 | <mediaobject> | ||
52 | <imageobject> | ||
53 | <imagedata fileref="screenshots/ss-anjuta-poky-1.png" format="PNG"/> | ||
54 | </imageobject> | ||
55 | <caption> | ||
56 | <para>The Anjuta Poky SDK plugin showing an active QEMU session running Sato</para> | ||
57 | </caption> | ||
58 | </mediaobject> | ||
59 | </screenshot> | ||
60 | --> | ||
61 | <para> | ||
62 | To use the plugin, a toolchain and SDK built by Poky is required along with Anjuta it's development | ||
63 | headers and the Anjuta plugin. The Poky Anjuta plugin is available to download as a tarball at the | ||
64 | <ulink url='http://labs.o-hand.com/anjuta-poky-sdk-plugin/'>OpenedHand labs</ulink> page or | ||
65 | directly from the Poky Git repository located at git://git.pokylinux.org/anjuta-poky; a web interface | ||
66 | to the repository can be accessed at <ulink url='http://git.pokylinux.org/?p=anjuta-poky.git;a=summary'/>. | ||
67 | </para> | ||
68 | <para> | ||
69 | See the README file contained in the project for more information on dependencies and building | ||
70 | the plugin. If you want to disable remote gdb debugging, please pass --diable-gdb-integration | ||
71 | switch when doing configure. | ||
72 | </para> | ||
73 | |||
74 | <section id="platdev-appdev-external-anjuta-setup"> | ||
75 | <title>Setting up the Anjuta plugin</title> | ||
76 | |||
77 | <para>Extract the tarball for the toolchain into / as root. The | ||
78 | toolchain will be installed into | ||
79 | <filename class="directory">/opt/poky</filename>.</para> | ||
80 | |||
81 | <para>To use the plugin, first open or create an existing | ||
82 | project. If creating a new project the "C GTK+" project type | ||
83 | will allow itself to be cross-compiled. However you should be | ||
84 | aware that this uses glade for the UI.</para> | ||
85 | |||
86 | <para>To activate the plugin go to | ||
87 | <menuchoice><guimenu>Edit</guimenu><guimenuitem>Preferences</guimenuitem></menuchoice>, | ||
88 | then choose <guilabel>General</guilabel> from the left hand side. Choose the | ||
89 | Installed plugins tab, scroll down to <guilabel>Poky | ||
90 | SDK</guilabel> and check the | ||
91 | box. The plugin is now activated but first it must be | ||
92 | configured.</para> | ||
93 | </section> | ||
94 | |||
95 | <section id="platdev-appdev-external-anjuta-configuration"> | ||
96 | <title>Configuring the Anjuta plugin</title> | ||
97 | |||
98 | <para>The configuration options for the SDK can be found by choosing | ||
99 | the <guilabel>Poky SDK</guilabel> icon from the left hand side. The following options | ||
100 | need to be set:</para> | ||
101 | |||
102 | <itemizedlist> | ||
103 | |||
104 | <listitem><para><guilabel>SDK root</guilabel>: If we use external toolchain, we need to set SDK root. | ||
105 | this is the root directory of the SDK's sysroot. For an i586 SDK this will be <filename | ||
106 | class="directory">/opt/poky/</filename>. | ||
107 | This directory will contain directories named like "bin", | ||
108 | "include", "var", etc. under your selected target architecture subdirectory<filename class="directory"> | ||
109 | /opt/poky/sysroot/i586-poky-linux/</filename>. Needed cross compile tools are under | ||
110 | <filename class ="directory">/opt/poky/sysroot/i586-pokysdk-linux/</filename> | ||
111 | </para></listitem> | ||
112 | |||
113 | <listitem><para><guilabel>Poky root</guilabel>: If we have local poky build tree, we need to set the Poky root. | ||
114 | this is the root directory of the poky build tree, if you build your i586 target architecture | ||
115 | under the subdirectory of build_x86 within your poky tree, the Poky root directory should be | ||
116 | <filename class="directory">${Poky_tree}/build_x86/</filename>. | ||
117 | </para></listitem> | ||
118 | |||
119 | <listitem><para><guilabel>Target Architecture</guilabel>: this is the cross compile | ||
120 | triplet, e.g. "i586-poky-linux". This target triplet is the prefix extracted from | ||
121 | the set up script file name. For examle, "i586-poky-linux" is extracted from set up script file | ||
122 | <filename>/opt/poky/environment-setup-i586-poky-linux</filename> | ||
123 | </para></listitem> | ||
124 | |||
125 | <listitem><para><guilabel>Kernel</guilabel>: use the file chooser to select the kernel | ||
126 | to use with QEMU</para></listitem> | ||
127 | |||
128 | <listitem><para><guilabel>Root filesystem</guilabel>: use the file chooser to select | ||
129 | the root filesystem directory, this is the directory where you use "poky-extract-sdk" command to | ||
130 | extract the poky-image-sdk tarball.</para></listitem> | ||
131 | </itemizedlist> | ||
132 | <!-- DISBALED, TOO BIG! | ||
133 | <screenshot> | ||
134 | <mediaobject> | ||
135 | <imageobject> | ||
136 | <imagedata fileref="screenshots/ss-anjuta-poky-2.png" format="PNG"/> | ||
137 | </imageobject> | ||
138 | <caption> | ||
139 | <para>Anjuta Preferences Dialog</para> | ||
140 | </caption> | ||
141 | </mediaobject> | ||
142 | </screenshot> | ||
143 | --> | ||
144 | |||
145 | </section> | ||
146 | |||
147 | <section id="platdev-appdev-external-anjuta-usage"> | ||
148 | <title>Using the Anjuta plugin</title> | ||
149 | |||
150 | <para>As an example, cross-compiling a project, deploying it into | ||
151 | QEMU and running a debugger against it and then doing a system | ||
152 | wide profile.</para> | ||
153 | |||
154 | <para>Choose <menuchoice><guimenu>Build</guimenu><guimenuitem>Run | ||
155 | Configure</guimenuitem></menuchoice> or | ||
156 | <menuchoice><guimenu>Build</guimenu><guimenuitem>Run | ||
157 | Autogenerate</guimenuitem></menuchoice> to run "configure" | ||
158 | (or to run "autogen") for the project. This passes command line | ||
159 | arguments to instruct it to cross-compile.</para> | ||
160 | |||
161 | <para>Next do | ||
162 | <menuchoice><guimenu>Build</guimenu><guimenuitem>Build | ||
163 | Project</guimenuitem></menuchoice> to build and compile the | ||
164 | project. If you have previously built the project in the same | ||
165 | tree without using the cross-compiler you may find that your | ||
166 | project fails to link. Simply do | ||
167 | <menuchoice><guimenu>Build</guimenu><guimenuitem>Clean | ||
168 | Project</guimenuitem></menuchoice> to remove the old | ||
169 | binaries. You may then try building again.</para> | ||
170 | |||
171 | <para>Next start QEMU by using | ||
172 | <menuchoice><guimenu>Tools</guimenu><guimenuitem>Start | ||
173 | QEMU</guimenuitem></menuchoice>, this will start QEMU and | ||
174 | will show any error messages in the message view. Once Poky has | ||
175 | fully booted within QEMU you may now deploy into it.</para> | ||
176 | |||
177 | <para>Once built and QEMU is running, choose | ||
178 | <menuchoice><guimenu>Tools</guimenu><guimenuitem>Deploy</guimenuitem></menuchoice>, | ||
179 | this will install the package into a temporary directory and | ||
180 | then copy using rsync over SSH into the target. Progress and | ||
181 | messages will be shown in the message view.</para> | ||
182 | |||
183 | <para>To debug a program installed into onto the target choose | ||
184 | <menuchoice><guimenu>Tools</guimenu><guimenuitem>Debug | ||
185 | remote</guimenuitem></menuchoice>. This prompts for the | ||
186 | local binary to debug and also the command line to run on the | ||
187 | target. The command line to run should include the full path to | ||
188 | the to binary installed in the target. This will start a | ||
189 | gdbserver over SSH on the target and also an instance of a | ||
190 | cross-gdb in a local terminal. This will be preloaded to connect | ||
191 | to the server and use the <guilabel>SDK root</guilabel> to find | ||
192 | symbols. This gdb will connect to the target and load in | ||
193 | various libraries and the target program. You should setup any | ||
194 | breakpoints or watchpoints now since you might not be able to | ||
195 | interrupt the execution later. You may stop | ||
196 | the debugger on the target using | ||
197 | <menuchoice><guimenu>Tools</guimenu><guimenuitem>Stop | ||
198 | debugger</guimenuitem></menuchoice>.</para> | ||
199 | |||
200 | <para>It is also possible to execute a command in the target over | ||
201 | SSH, the appropriate environment will be be set for the | ||
202 | execution. Choose | ||
203 | <menuchoice><guimenu>Tools</guimenu><guimenuitem>Run | ||
204 | remote</guimenuitem></menuchoice> to do this. This will open | ||
205 | a terminal with the SSH command inside.</para> | ||
206 | |||
207 | <para>To do a system wide profile against the system running in | ||
208 | QEMU choose | ||
209 | <menuchoice><guimenu>Tools</guimenu><guimenuitem>Profile | ||
210 | remote</guimenuitem></menuchoice>. This will start up | ||
211 | OProfileUI with the appropriate parameters to connect to the | ||
212 | server running inside QEMU and will also supply the path to the | ||
213 | debug information necessary to get a useful profile.</para> | ||
214 | |||
215 | </section> | ||
216 | </section> | ||
217 | |||
218 | |||
219 | <section id="platdev-appdev-qemu"> | ||
220 | <title>Developing externally in QEMU</title> | ||
221 | <para> | ||
222 | Running Poky QEMU images is covered in the <link | ||
223 | linkend='intro-quickstart-qemu'>Running an Image</link> section. | ||
224 | </para> | ||
225 | <para> | ||
226 | Poky's QEMU images contain a complete native toolchain. This means | ||
227 | that applications can be developed within QEMU in the same was as a | ||
228 | normal system. Using qemux86 on an x86 machine is fast since the | ||
229 | guest and host architectures match, qemuarm is slower but gives | ||
230 | faithful emulation of ARM specific issues. To speed things up these | ||
231 | images support using distcc to call a cross-compiler outside the | ||
232 | emulated system too. If <command>runqemu</command> was used to start | ||
233 | QEMU, and distccd is present on the host system, any bitbake cross | ||
234 | compiling toolchain available from the build system will automatically | ||
235 | be used from within qemu simply by calling distcc | ||
236 | (<command>export CC="distcc"</command> can be set in the enviroment). | ||
237 | Alterntatively, if a suitable SDK/toolchain is present in | ||
238 | <filename class="directory">/opt/poky</filename> it will also | ||
239 | automatically be used. | ||
240 | </para> | ||
241 | |||
242 | <para> | ||
243 | There are several options for connecting into the emulated system. | ||
244 | QEMU provides a framebuffer interface which has standard consoles | ||
245 | available. There is also a serial connection available which has a | ||
246 | console to the system running on it and IP networking as standard. | ||
247 | The images have a dropbear ssh server running with the root password | ||
248 | disabled allowing standard ssh and scp commands to work. The images | ||
249 | also contain an NFS server exporting the guest's root filesystem | ||
250 | allowing that to be made available to the host. | ||
251 | </para> | ||
252 | </section> | ||
253 | |||
254 | <section id="platdev-appdev-insitu"> | ||
255 | <title>Developing in Poky directly</title> | ||
256 | <para> | ||
257 | Working directly in Poky is a fast and effective development technique. | ||
258 | The idea is that you can directly edit files in | ||
259 | <glossterm><link linkend='var-WORKDIR'>WORKDIR</link></glossterm> | ||
260 | or the source directory <glossterm><link linkend='var-S'>S</link></glossterm> | ||
261 | and then force specific tasks to rerun in order to test the changes. | ||
262 | An example session working on the matchbox-desktop package might | ||
263 | look like this: | ||
264 | </para> | ||
265 | |||
266 | <para> | ||
267 | <literallayout class='monospaced'> | ||
268 | $ bitbake matchbox-desktop | ||
269 | $ sh | ||
270 | $ cd tmp/work/armv5te-poky-linux-gnueabi/matchbox-desktop-2.0+svnr1708-r0/ | ||
271 | $ cd matchbox-desktop-2 | ||
272 | $ vi src/main.c | ||
273 | $ exit | ||
274 | $ bitbake matchbox-desktop -c compile -f | ||
275 | $ bitbake matchbox-desktop | ||
276 | </literallayout> | ||
277 | </para> | ||
278 | |||
279 | <para> | ||
280 | Here, we build the package, change into the work directory for the package, | ||
281 | change a file, then recompile the package. Instead of using sh like this, | ||
282 | you can also use two different terminals. The risk with working like this | ||
283 | is that a command like unpack could wipe out the changes you've made to the | ||
284 | work directory so you need to work carefully. | ||
285 | </para> | ||
286 | |||
287 | <para> | ||
288 | It is useful when making changes directly to the work directory files to do | ||
289 | so using quilt as detailed in the <link linkend='usingpoky-modifying-packages-quilt'> | ||
290 | modifying packages with quilt</link> section. The resulting patches can be copied | ||
291 | into the recipe directory and used directly in the <glossterm><link | ||
292 | linkend='var-SRC_URI'>SRC_URI</link></glossterm>. | ||
293 | </para> | ||
294 | <para> | ||
295 | For a review of the skills used in this section see Sections <link | ||
296 | linkend="usingpoky-components-bitbake">2.1.1</link> and <link | ||
297 | linkend="usingpoky-debugging-taskrunning">2.4.2</link>. | ||
298 | </para> | ||
299 | |||
300 | </section> | ||
301 | |||
302 | <section id="platdev-appdev-devshell"> | ||
303 | <title>Developing with 'devshell'</title> | ||
304 | |||
305 | <para> | ||
306 | When debugging certain commands or even to just edit packages, the | ||
307 | 'devshell' can be a useful tool. To start it you run a command like: | ||
308 | </para> | ||
309 | |||
310 | <para> | ||
311 | <literallayout class='monospaced'> | ||
312 | $ bitbake matchbox-desktop -c devshell | ||
313 | </literallayout> | ||
314 | </para> | ||
315 | |||
316 | <para> | ||
317 | which will open a terminal with a shell prompt within the Poky | ||
318 | environment. This means PATH is setup to include the cross toolchain, | ||
319 | the pkgconfig variables are setup to find the right .pc files, | ||
320 | configure will be able to find the Poky site files etc. Within this | ||
321 | environment, you can run configure or compile command as if they | ||
322 | were being run by Poky itself. You are also changed into the | ||
323 | source (<glossterm><link linkend='var-S'>S</link></glossterm>) | ||
324 | directory automatically. When finished with the shell just exit it | ||
325 | or close the terminal window. | ||
326 | </para> | ||
327 | |||
328 | <para> | ||
329 | The default shell used by devshell is the gnome-terminal. Other | ||
330 | forms of terminal can also be used by setting the <glossterm> | ||
331 | <link linkend='var-TERMCMD'>TERMCMD</link></glossterm> and <glossterm> | ||
332 | <link linkend='var-TERMCMDRUN'>TERMCMDRUN</link></glossterm> variables | ||
333 | in local.conf. For examples of the other options available, see | ||
334 | <filename>meta/conf/bitbake.conf</filename>. An external shell is | ||
335 | launched rather than opening directly into the original terminal | ||
336 | window to make interaction with bitbakes multiple threads easier | ||
337 | and also allow a client/server split of bitbake in the future | ||
338 | (devshell will still work over X11 forwarding or similar). | ||
339 | </para> | ||
340 | |||
341 | <para> | ||
342 | It is worth remembering that inside devshell you need to use the full | ||
343 | compiler name such as <command>arm-poky-linux-gnueabi-gcc</command> | ||
344 | instead of just <command>gcc</command> and the same applies to other | ||
345 | applications from gcc, bintuils, libtool etc. Poky will have setup | ||
346 | environmental variables such as CC to assist applications, such as make, | ||
347 | find the correct tools. | ||
348 | </para> | ||
349 | |||
350 | </section> | ||
351 | |||
352 | <section id="platdev-appdev-srcrev"> | ||
353 | <title>Developing within Poky with an external SCM based package</title> | ||
354 | |||
355 | <para> | ||
356 | If you're working on a recipe which pulls from an external SCM it | ||
357 | is possible to have Poky notice new changes added to the | ||
358 | SCM and then build the latest version. This only works for SCMs | ||
359 | where its possible to get a sensible revision number for changes. | ||
360 | Currently it works for svn, git and bzr repositories. | ||
361 | </para> | ||
362 | |||
363 | <para> | ||
364 | To enable this behaviour it is simply a case of adding <glossterm> | ||
365 | <link linkend='var-SRCREV'>SRCREV</link></glossterm>_pn-<glossterm> | ||
366 | <link linkend='var-PN'>PN</link></glossterm> = "${AUTOREV}" to | ||
367 | local.conf where <glossterm><link linkend='var-PN'>PN</link></glossterm> | ||
368 | is the name of the package for which you want to enable automatic source | ||
369 | revision updating. | ||
370 | </para> | ||
371 | </section> | ||
372 | |||
373 | </section> | ||
374 | |||
375 | <section id="platdev-gdb-remotedebug"> | ||
376 | <title>Debugging with GDB Remotely</title> | ||
377 | |||
378 | <para> | ||
379 | <ulink url="http://sourceware.org/gdb/">GDB</ulink> (The GNU Project Debugger) | ||
380 | allows you to examine running programs to understand and fix problems and | ||
381 | also to perform postmortem style analsys of program crashes. It is available | ||
382 | as a package within poky and installed by default in sdk images. It works best | ||
383 | when -dbg packages for the application being debugged are installed as the | ||
384 | extra symbols give more meaningful output from GDB. | ||
385 | </para> | ||
386 | |||
387 | <para> | ||
388 | Sometimes, due to memory or disk space constraints, it is not possible | ||
389 | to use GDB directly on the remote target to debug applications. This is | ||
390 | due to the fact that | ||
391 | GDB needs to load the debugging information and the binaries of the | ||
392 | process being debugged. GDB then needs to perform many | ||
393 | computations to locate information such as function names, variable | ||
394 | names and values, stack traces, etc. even before starting the debugging | ||
395 | process. This places load on the target system and can alter the | ||
396 | characteristics of the program being debugged. | ||
397 | </para> | ||
398 | <para> | ||
399 | This is where GDBSERVER comes into play as it runs on the remote target | ||
400 | and does not load any debugging information from the debugged process. | ||
401 | Instead, the debugging information processing is done by a GDB instance | ||
402 | running on a distant computer - the host GDB. The host GDB then sends | ||
403 | control commands to GDBSERVER to make it stop or start the debugged | ||
404 | program, as well as read or write some memory regions of that debugged | ||
405 | program. All the debugging information loading and processing as well | ||
406 | as the heavy debugging duty is done by the host GDB, giving the | ||
407 | GDBSERVER running on the target a chance to remain small and fast. | ||
408 | </para> | ||
409 | <para> | ||
410 | As the host GDB is responsible for loading the debugging information and | ||
411 | doing the necessary processing to make actual debugging happen, the | ||
412 | user has to make sure it can access the unstripped binaries complete | ||
413 | with their debugging information and compiled with no optimisations. The | ||
414 | host GDB must also have local access to all the libraries used by the | ||
415 | debugged program. On the remote target the binaries can remain stripped | ||
416 | as GDBSERVER does not need any debugging information there. However they | ||
417 | must also be compiled without optimisation matching the host's binaries. | ||
418 | </para> | ||
419 | |||
420 | <para> | ||
421 | The binary being debugged on the remote target machine is hence referred | ||
422 | to as the 'inferior' in keeping with GDB documentation and terminology. | ||
423 | Further documentation on GDB, is available on | ||
424 | <ulink url="http://sourceware.org/gdb/documentation/">on their site</ulink>. | ||
425 | </para> | ||
426 | |||
427 | <section id="platdev-gdb-remotedebug-launch-gdbserver"> | ||
428 | <title>Launching GDBSERVER on the target</title> | ||
429 | <para> | ||
430 | First, make sure gdbserver is installed on the target. If not, | ||
431 | install the gdbserver package (which needs the libthread-db1 | ||
432 | package). | ||
433 | </para> | ||
434 | <para> | ||
435 | To launch GDBSERVER on the target and make it ready to "debug" a | ||
436 | program located at <emphasis>/path/to/inferior</emphasis>, connect | ||
437 | to the target and launch: | ||
438 | <programlisting>$ gdbserver localhost:2345 /path/to/inferior</programlisting> | ||
439 | After that, gdbserver should be listening on port 2345 for debugging | ||
440 | commands coming from a remote GDB process running on the host computer. | ||
441 | Communication between the GDBSERVER and the host GDB will be done using | ||
442 | TCP. To use other communication protocols please refer to the | ||
443 | GDBSERVER documentation. | ||
444 | </para> | ||
445 | </section> | ||
446 | |||
447 | <section id="platdev-gdb-remotedebug-launch-gdb"> | ||
448 | <title>Launching GDB on the host computer</title> | ||
449 | |||
450 | <para> | ||
451 | Running GDB on the host computer takes a number of stages, described in the | ||
452 | following sections. | ||
453 | </para> | ||
454 | |||
455 | <section id="platdev-gdb-remotedebug-launch-gdb-buildcross"> | ||
456 | <title>Build the cross GDB package</title> | ||
457 | <para> | ||
458 | A suitable gdb cross binary is required which runs on your host computer but | ||
459 | knows about the the ABI of the remote target. This can be obtained from | ||
460 | the the Poky toolchain, e.g. | ||
461 | <filename>/opt/poky/sysroots/x86_64-pokysdk-linux/usr/bin/armv5te-poky-linux-gnueabi/arm-poky-linux-gnueabi-gdb</filename> | ||
462 | which "x86_64" is the host architecture, "arm" is the target architecture and "linux-gnueabi" the target ABI. | ||
463 | </para> | ||
464 | |||
465 | <para> | ||
466 | Alternatively this can be built directly by Poky. To do this you would build | ||
467 | the gdb-cross package so for example you would run: | ||
468 | <programlisting>bitbake gdb-cross</programlisting> | ||
469 | Once built, the cross gdb binary can be found at | ||
470 | <programlisting>tmp/sysroots/<host-arch>/usr/bin/\ | ||
471 | <target-arch>-poky-<target-abi>/<target-arch>-poky-<target-abi>-gdb </programlisting> | ||
472 | </para> | ||
473 | |||
474 | </section> | ||
475 | <section id="platdev-gdb-remotedebug-launch-gdb-inferiorbins"> | ||
476 | |||
477 | <title>Making the inferior binaries available</title> | ||
478 | |||
479 | <para> | ||
480 | The inferior binary needs to be available to GDB complete with all debugging | ||
481 | symbols in order to get the best possible results along with any libraries | ||
482 | the inferior depends on and their debugging symbols. There are a number of | ||
483 | ways this can be done. | ||
484 | </para> | ||
485 | |||
486 | <para> | ||
487 | Perhaps the easiest is to have an 'sdk' image corresponding to the plain | ||
488 | image installed on the device. In the case of 'pky-image-sato', | ||
489 | 'poky-image-sdk' would contain suitable symbols. The sdk images already | ||
490 | have the debugging symbols installed so its just a question expanding the | ||
491 | archive to some location and telling GDB where this is. | ||
492 | </para> | ||
493 | |||
494 | <para> | ||
495 | Alternatively, poky can build a custom directory of files for a specific | ||
496 | debugging purpose by reusing its tmp/rootfs directory, on the host computer | ||
497 | in a slightly different way to normal. This directory contains the contents | ||
498 | of the last built image. This process assumes the image running on the | ||
499 | target was the last image to be built by Poky, the package <emphasis>foo</emphasis> | ||
500 | contains the inferior binary to be debugged has been built without without | ||
501 | optimisation and has debugging information available. | ||
502 | </para> | ||
503 | <para> | ||
504 | Firstly you want to install the <emphasis>foo</emphasis> package to tmp/rootfs | ||
505 | by doing: | ||
506 | </para> | ||
507 | <programlisting>tmp/sysroots/i686-linux/usr/bin/opkg-cl -f \ | ||
508 | tmp/work/<target-abi>/poky-image-sato-1.0-r0/opkg.conf -o \ | ||
509 | tmp/rootfs/ update</programlisting> | ||
510 | <para> | ||
511 | then, | ||
512 | </para> | ||
513 | <programlisting>tmp/sysroots/i686-linux/usr/bin/opkg-cl -f \ | ||
514 | tmp/work/<target-abi>/poky-image-sato-1.0-r0/opkg.conf \ | ||
515 | -o tmp/rootfs install foo | ||
516 | |||
517 | tmp/sysroots/i686-linux/usr/bin/opkg-cl -f \ | ||
518 | tmp/work/<target-abi>/poky-image-sato-1.0-r0/opkg.conf \ | ||
519 | -o tmp/rootfs install foo-dbg</programlisting> | ||
520 | <para> | ||
521 | which installs the debugging information too. | ||
522 | </para> | ||
523 | |||
524 | </section> | ||
525 | <section id="platdev-gdb-remotedebug-launch-gdb-launchhost"> | ||
526 | |||
527 | <title>Launch the host GDB</title> | ||
528 | <para> | ||
529 | To launch the host GDB, run the cross gdb binary identified above with | ||
530 | the inferior binary specified on the commandline: | ||
531 | <programlisting><target-arch>-poky-<target-abi>-gdb rootfs/usr/bin/foo</programlisting> | ||
532 | This loads the binary of program <emphasis>foo</emphasis> | ||
533 | as well as its debugging information. Once the gdb prompt | ||
534 | appears, you must instruct GDB to load all the libraries | ||
535 | of the inferior from tmp/rootfs: | ||
536 | <programlisting>set solib-absolute-prefix /path/to/tmp/rootfs</programlisting> | ||
537 | where <filename>/path/to/tmp/rootfs</filename> must be | ||
538 | the absolute path to <filename>tmp/rootfs</filename> or wherever the | ||
539 | binaries with debugging information are located. | ||
540 | </para> | ||
541 | <para> | ||
542 | Now, tell GDB to connect to the GDBSERVER running on the remote target: | ||
543 | <programlisting>target remote remote-target-ip-address:2345</programlisting> | ||
544 | Where remote-target-ip-address is the IP address of the | ||
545 | remote target where the GDBSERVER is running. 2345 is the | ||
546 | port on which the GDBSERVER is running. | ||
547 | </para> | ||
548 | |||
549 | </section> | ||
550 | <section id="platdev-gdb-remotedebug-launch-gdb-using"> | ||
551 | |||
552 | <title>Using the Debugger</title> | ||
553 | <para> | ||
554 | Debugging can now proceed as normal, as if the debugging were being done on the | ||
555 | local machine, for example to tell GDB to break in the <emphasis>main</emphasis> | ||
556 | function, for instance: | ||
557 | <programlisting>break main</programlisting> | ||
558 | and then to tell GDB to "continue" the inferior execution, | ||
559 | <programlisting>continue</programlisting> | ||
560 | </para> | ||
561 | <para> | ||
562 | For more information about using GDB please see the | ||
563 | project's online documentation at <ulink | ||
564 | url="http://sourceware.org/gdb/download/onlinedocs/"/>. | ||
565 | </para> | ||
566 | </section> | ||
567 | </section> | ||
568 | |||
569 | </section> | ||
570 | |||
571 | <section id="platdev-oprofile"> | ||
572 | <title>Profiling with OProfile</title> | ||
573 | |||
574 | <para> | ||
575 | <ulink url="http://oprofile.sourceforge.net/">OProfile</ulink> is a | ||
576 | statistical profiler well suited to finding performance | ||
577 | bottlenecks in both userspace software and the kernel. It provides | ||
578 | answers to questions like "Which functions does my application spend | ||
579 | the most time in when doing X?". Poky is well integrated with OProfile | ||
580 | to make profiling applications on target hardware straightforward. | ||
581 | </para> | ||
582 | |||
583 | <para> | ||
584 | To use OProfile you need an image with OProfile installed. The easiest | ||
585 | way to do this is with "tools-profile" in <glossterm><link | ||
586 | linkend='var-IMAGE_FEATURES'>IMAGE_FEATURES</link></glossterm>. You also | ||
587 | need debugging symbols to be available on the system where the analysis | ||
588 | will take place. This can be achieved with "dbg-pkgs" in <glossterm><link | ||
589 | linkend='var-IMAGE_FEATURES'>IMAGE_FEATURES</link></glossterm> or by | ||
590 | installing the appropriate -dbg packages. For | ||
591 | successful call graph analysis the binaries must preserve the frame | ||
592 | pointer register and hence should be compiled with the | ||
593 | "-fno-omit-framepointer" flag. In Poky this can be achieved with | ||
594 | <glossterm><link linkend='var-SELECTED_OPTIMIZATION'>SELECTED_OPTIMIZATION | ||
595 | </link></glossterm> = "-fexpensive-optimizations -fno-omit-framepointer | ||
596 | -frename-registers -O2" or by setting <glossterm><link | ||
597 | linkend='var-DEBUG_BUILD'>DEBUG_BUILD</link></glossterm> = "1" in | ||
598 | local.conf (the latter will also add extra debug information making the | ||
599 | debug packages large). | ||
600 | </para> | ||
601 | |||
602 | <section id="platdev-oprofile-target"> | ||
603 | <title>Profiling on the target</title> | ||
604 | |||
605 | <para> | ||
606 | All the profiling work can be performed on the target device. A | ||
607 | simple OProfile session might look like: | ||
608 | </para> | ||
609 | |||
610 | <para> | ||
611 | <literallayout class='monospaced'> | ||
612 | # opcontrol --reset | ||
613 | # opcontrol --start --separate=lib --no-vmlinux -c 5 | ||
614 | [do whatever is being profiled] | ||
615 | # opcontrol --stop | ||
616 | $ opreport -cl | ||
617 | </literallayout> | ||
618 | </para> | ||
619 | |||
620 | <para> | ||
621 | Here, the reset command clears any previously profiled data, | ||
622 | OProfile is then started. The options used to start OProfile mean | ||
623 | dynamic library data is kept separately per application, kernel | ||
624 | profiling is disabled and callgraphing is enabled up to 5 levels | ||
625 | deep. To profile the kernel, you would specify the | ||
626 | <parameter>--vmlinux=/path/to/vmlinux</parameter> option (the vmlinux file is usually in | ||
627 | <filename class="directory">/boot/</filename> in Poky and must match the running kernel). The profile is | ||
628 | then stopped and the results viewed with opreport with options | ||
629 | to see the separate library symbols and callgraph information. | ||
630 | </para> | ||
631 | <para> | ||
632 | Callgraphing means OProfile not only logs infomation about which | ||
633 | functions time is being spent in but also which functions | ||
634 | called those functions (their parents) and which functions that | ||
635 | function calls (its children). The higher the callgraphing depth, | ||
636 | the more accurate the results but this also increased the loging | ||
637 | overhead so it should be used with caution. On ARM, binaries need | ||
638 | to have the frame pointer enabled for callgraphing to work (compile | ||
639 | with the gcc option -fno-omit-framepointer). | ||
640 | </para> | ||
641 | <para> | ||
642 | For more information on using OProfile please see the OProfile | ||
643 | online documentation at <ulink | ||
644 | url="http://oprofile.sourceforge.net/docs/"/>. | ||
645 | </para> | ||
646 | </section> | ||
647 | |||
648 | <section id="platdev-oprofile-oprofileui"> | ||
649 | <title>Using OProfileUI</title> | ||
650 | |||
651 | <para> | ||
652 | A graphical user interface for OProfile is also available. You can | ||
653 | either use prebuilt Debian packages from the <ulink | ||
654 | url='http://debian.o-hand.com/'>OpenedHand repository</ulink> or | ||
655 | download and build from svn at | ||
656 | http://svn.o-hand.com/repos/oprofileui/trunk/. If the | ||
657 | "tools-profile" image feature is selected, all necessary binaries | ||
658 | are installed onto the target device for OProfileUI interaction. | ||
659 | </para> | ||
660 | |||
661 | <!-- DISBALED, Need a more 'contexual' shot? | ||
662 | <screenshot> | ||
663 | <mediaobject> | ||
664 | <imageobject> | ||
665 | <imagedata fileref="screenshots/ss-oprofile-viewer.png" format="PNG"/> | ||
666 | </imageobject> | ||
667 | <caption> | ||
668 | <para>OProfileUI Viewer showing an application being profiled on a remote device</para> | ||
669 | </caption> | ||
670 | </mediaobject> | ||
671 | </screenshot> | ||
672 | --> | ||
673 | <para> | ||
674 | In order to convert the data in the sample format from the target | ||
675 | to the host the <filename>opimport</filename> program is needed. | ||
676 | This is not included in standard Debian OProfile packages but an | ||
677 | OProfile package with this addition is also available from the <ulink | ||
678 | url='http://debian.o-hand.com/'>OpenedHand repository</ulink>. | ||
679 | We recommend using OProfile 0.9.3 or greater. Other patches to | ||
680 | OProfile may be needed for recent OProfileUI features, but Poky | ||
681 | usually includes all needed patches on the target device. Please | ||
682 | see the <ulink | ||
683 | url='http://svn.o-hand.com/repos/oprofileui/trunk/README'> | ||
684 | OProfileUI README</ulink> for up to date information, and the | ||
685 | <ulink url="http://labs.o-hand.com/oprofileui">OProfileUI website | ||
686 | </ulink> for more information on the OProfileUI project. | ||
687 | </para> | ||
688 | |||
689 | <section id="platdev-oprofile-oprofileui-online"> | ||
690 | <title>Online mode</title> | ||
691 | |||
692 | <para> | ||
693 | This assumes a working network connection with the target | ||
694 | hardware. In this case you just need to run <command> | ||
695 | "oprofile-server"</command> on the device. By default it listens | ||
696 | on port 4224. This can be changed with the <parameter>--port</parameter> command line | ||
697 | option. | ||
698 | |||
699 | </para> | ||
700 | |||
701 | <para> | ||
702 | The client program is called <command>oprofile-viewer</command>. The | ||
703 | UI is relatively straightforward, the key functionality is accessed | ||
704 | through the buttons on the toolbar (which are duplicated in the | ||
705 | menus.) These buttons are: | ||
706 | </para> | ||
707 | |||
708 | <itemizedlist> | ||
709 | <listitem> | ||
710 | <para> | ||
711 | Connect - connect to the remote host, the IP address or hostname for the | ||
712 | target can be supplied here. | ||
713 | </para> | ||
714 | </listitem> | ||
715 | <listitem> | ||
716 | <para> | ||
717 | Disconnect - disconnect from the target. | ||
718 | </para> | ||
719 | </listitem> | ||
720 | <listitem> | ||
721 | <para> | ||
722 | Start - start the profiling on the device. | ||
723 | </para> | ||
724 | </listitem> | ||
725 | <listitem> | ||
726 | <para> | ||
727 | Stop - stop the profiling on the device and download the data to the local | ||
728 | host. This will generate the profile and show it in the viewer. | ||
729 | </para> | ||
730 | </listitem> | ||
731 | <listitem> | ||
732 | <para> | ||
733 | Download - download the data from the target, generate the profile and show it | ||
734 | in the viewer. | ||
735 | </para> | ||
736 | </listitem> | ||
737 | <listitem> | ||
738 | <para> | ||
739 | Reset - reset the sample data on the device. This will remove the sample | ||
740 | information that was collected on a previous sampling run. Ensure you do this | ||
741 | if you do not want to include old sample information. | ||
742 | </para> | ||
743 | </listitem> | ||
744 | <listitem> | ||
745 | <para> | ||
746 | Save - save the data downloaded from the target to another directory for later | ||
747 | examination. | ||
748 | </para> | ||
749 | </listitem> | ||
750 | <listitem> | ||
751 | <para> | ||
752 | Open - load data that was previously saved. | ||
753 | </para> | ||
754 | </listitem> | ||
755 | </itemizedlist> | ||
756 | |||
757 | <para> | ||
758 | The behaviour of the client is to download the complete 'profile archive' from | ||
759 | the target to the host for processing. This archive is a directory containing | ||
760 | the sample data, the object files and the debug information for said object | ||
761 | files. This archive is then converted using a script included in this | ||
762 | distribution ('oparchconv') that uses 'opimport' to convert the archive from | ||
763 | the target to something that can be processed on the host. | ||
764 | </para> | ||
765 | |||
766 | <para> | ||
767 | Downloaded archives are kept in /tmp and cleared up when they are no longer in | ||
768 | use. | ||
769 | </para> | ||
770 | |||
771 | <para> | ||
772 | If you wish to profile into the kernel, this is possible, you just need to ensure | ||
773 | a vmlinux file matching the running kernel is available. In Poky this is usually | ||
774 | located in /boot/vmlinux-KERNELVERSION, where KERNEL-version is the version of | ||
775 | the kernel e.g. 2.6.23. Poky generates separate vmlinux packages for each kernel | ||
776 | it builds so it should be a question of just ensuring a matching package is | ||
777 | installed (<command> opkg install kernel-vmlinux</command>. These are automatically | ||
778 | installed into development and profiling images alongside OProfile. There is a | ||
779 | configuration option within the OProfileUI settings page where the location of | ||
780 | the vmlinux file can be entered. | ||
781 | </para> | ||
782 | |||
783 | <para> | ||
784 | Waiting for debug symbols to transfer from the device can be slow and it's not | ||
785 | always necessary to actually have them on device for OProfile use. All that is | ||
786 | needed is a copy of the filesystem with the debug symbols present on the viewer | ||
787 | system. The <link linkend='platdev-gdb-remotedebug-launch-gdb'>GDB remote debug | ||
788 | section</link> covers how to create such a directory with Poky and the location | ||
789 | of this directory can again be specified in the OProfileUI settings dialog. If | ||
790 | specified, it will be used where the file checksums match those on the system | ||
791 | being profiled. | ||
792 | </para> | ||
793 | </section> | ||
794 | <section id="platdev-oprofile-oprofileui-offline"> | ||
795 | <title>Offline mode</title> | ||
796 | |||
797 | <para> | ||
798 | If no network access to the target is available an archive for processing in | ||
799 | 'oprofile-viewer' can be generated with the following set of command. | ||
800 | </para> | ||
801 | |||
802 | <para> | ||
803 | <literallayout class='monospaced'> | ||
804 | # opcontrol --reset | ||
805 | # opcontrol --start --separate=lib --no-vmlinux -c 5 | ||
806 | [do whatever is being profiled] | ||
807 | # opcontrol --stop | ||
808 | # oparchive -o my_archive | ||
809 | </literallayout> | ||
810 | </para> | ||
811 | |||
812 | <para> | ||
813 | Where my_archive is the name of the archive directory where you would like the | ||
814 | profile archive to be kept. The directory will be created for you. This can | ||
815 | then be copied to another host and loaded using 'oprofile-viewer''s open | ||
816 | functionality. The archive will be converted if necessary. | ||
817 | </para> | ||
818 | </section> | ||
819 | </section> | ||
820 | </section> | ||
821 | |||
822 | </chapter> | ||
823 | <!-- | ||
824 | vim: expandtab tw=80 ts=4 | ||
825 | --> | ||