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authorScott Rifenbark <srifenbark@gmail.com>2016-08-22 13:13:14 -0700
committerRichard Purdie <richard.purdie@linuxfoundation.org>2016-08-25 23:09:29 +0100
commit1769e1a2dec036dbe950b86dbdc95ab5798ece38 (patch)
tree04046dabf99cfac8daf8329b26f177fbdd8fe195
parenta2e8f196d735c16bf89a6753691262b0e46fd60f (diff)
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ref-manual: Suggested fleshing out of the sigdata/siginfo documentation
Fixes [YOCTO #10141] Provided several fixes to address this situation: * Renamed "Debugging Build Failures" to "Debugging Tools and Techniques" as it fit better the subsections. * Renamed "Viewing Dependencies" to "Viewing Dependencies Between Recipes and Tasks" as it fit better the description. * Added a new "Viewing Task Variable Dependencies" section to describe how sigdata and siginfo stuff can be used. * Replaced the contents of "4.3.4.1 Debugging" with a shorter bit that now references into the new section on veiwing task variable dependencies. (From yocto-docs rev: 539d76366055bed74ccc926519e969324cac470d) Signed-off-by: Scott Rifenbark <srifenbark@gmail.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
-rw-r--r--documentation/ref-manual/technical-details.xml59
-rw-r--r--documentation/ref-manual/usingpoky.xml125
2 files changed, 130 insertions, 54 deletions
diff --git a/documentation/ref-manual/technical-details.xml b/documentation/ref-manual/technical-details.xml
index 5ef764c8e0..6bad547e50 100644
--- a/documentation/ref-manual/technical-details.xml
+++ b/documentation/ref-manual/technical-details.xml
@@ -901,56 +901,15 @@
<title>Debugging</title>
<para>
- When things go wrong, debugging needs to be straightforward.
- Because of this, the Yocto Project includes strong debugging
- tools:
- <itemizedlist>
- <listitem><para>Whenever a shared state package is written
- out into the
- <link linkend='var-SSTATE_DIR'><filename>SSTATE_DIR</filename></link>,
- a corresponding <filename>.siginfo</filename> file is
- also written.
- This file contains a pickled Python database of all
- the Metadata that went into creating the hash for a
- given shared state package.
- Whenever a stamp is written into the stamp directory
- <link linkend='var-STAMP'><filename>STAMP</filename></link>,
- a corresponding <filename>.sigdata</filename> file
- is created that contains the same hash data that
- represented the executed task.
- </para></listitem>
- <listitem><para>You can use BitBake to dump out the
- signature construction information without executing
- tasks by using either of the following BitBake
- command-line options:
- <literallayout class='monospaced'>
- &dash;&dash;dump-signatures=<replaceable>SIGNATURE_HANDLER</replaceable>
- -S <replaceable>SIGNATURE_HANDLER</replaceable>
- </literallayout>
- <note>
- Two common values for
- <replaceable>SIGNATURE_HANDLER</replaceable> are
- "none" and "printdiff" to only dump the signature
- or to compare the dumped signature with the
- cached one, respectively.
- </note>
- Using BitBake with either of these options causes
- BitBake to dump out <filename>.sigdata</filename> files
- in the stamp directory for every task it would have
- executed instead of building the specified target
- package.
- </para></listitem>
- <listitem><para>There is a
- <filename>bitbake-diffsigs</filename> command that
- can process <filename>.sigdata</filename> and
- <filename>.siginfo</filename> files.
- If you specify one of these files, BitBake dumps out
- the dependency information in the file.
- If you specify two files, BitBake compares the two
- files and dumps out the differences between the two.
- This more easily helps answer the question of "What
- changed between X and Y?"</para></listitem>
- </itemizedlist>
+ Seeing what metadata went into creating the input signature
+ of a shared state (sstate) task can be a useful debugging aid.
+ This information is available in signature information
+ (<filename>siginfo</filename>) files in
+ <link linkend='var-SSTATE_DIR'><filename>SSTATE_DIR</filename></link>.
+ For information on how to view and interpret information in
+ <filename>siginfo</filename> files, see the
+ "<link linkend='usingpoky-viewing-task-variable-dependencies'>Viewing Task Variable Dependencies</link>"
+ section.
</para>
</section>
diff --git a/documentation/ref-manual/usingpoky.xml b/documentation/ref-manual/usingpoky.xml
index 15e1d47301..574de7b4b7 100644
--- a/documentation/ref-manual/usingpoky.xml
+++ b/documentation/ref-manual/usingpoky.xml
@@ -119,8 +119,8 @@
</para>
</section>
-<section id='usingpoky-debugging'>
- <title>Debugging Build Failures</title>
+<section id='usingpoky-debugging-tools-and-techniques'>
+ <title>Debugging Tools and Techniques</title>
<para>
The exact method for debugging build failures depends on the nature of
@@ -247,8 +247,8 @@
</para>
</section>
- <section id='usingpoky-viewing-dependencies'>
- <title>Viewing Dependencies</title>
+ <section id='usingpoky-viewing-dependencies-between-recipes-and-tasks'>
+ <title>Viewing Dependencies Between Recipes and Tasks</title>
<para>
Sometimes it can be hard to see why BitBake wants to build other
@@ -348,6 +348,123 @@
</para>
</section>
+ <section id='usingpoky-viewing-task-variable-dependencies'>
+ <title>Viewing Task Variable Dependencies</title>
+
+ <para>
+ As mentioned in the
+ "<ulink url='&YOCTO_DOCS_BB_URL;#checksums'>Checksums (Signatures)</ulink>"
+ section of the BitBake User Manual, BitBake tries to automatically
+ determine what variables a task depends on so that it can rerun
+ the task if any values of the variables change.
+ This determination is usually reliable.
+ However, if you do things like construct variable names at runtime,
+ then you might have to manually declare dependencies on those
+ variables using <filename>vardeps</filename> as described in the
+ "<ulink url='&YOCTO_DOCS_BB_URL;#variable-flags'>Variable Flags</ulink>"
+ section of the BitBake User Manual.
+ </para>
+
+ <para>
+ If you are unsure whether a variable dependency is being picked up
+ automatically for a given task, you can list the variable
+ dependencies BitBake has determined by doing the following:
+ <orderedlist>
+ <listitem><para>
+ Build the recipe containing the task:
+ <literallayout class='monospaced'>
+ $ bitbake <replaceable>recipename</replaceable>
+ </literallayout>
+ </para></listitem>
+ <listitem><para>
+ Inside the
+ <link linkend='var-STAMPS_DIR'><filename>STAMPS_DIR</filename></link>
+ directory, find the signature data
+ (<filename>sigdata</filename>) file that corresponds to the
+ task.
+ The <filename>sigdata</filename> files contain a pickled
+ Python database of all the metadata that went into creating
+ the input checksum for the task.
+ As an example, for the
+ <link linkend='ref-tasks-fetch'><filename>do_fetch</filename></link>
+ task of the <filename>db</filename> recipe, the
+ <filename>sigdata</filename> file might be found in the
+ following location:
+ <literallayout class='monospaced'>
+ ${BUILDDIR}/tmp/stamps/i586-poky-linux/db/6.0.30-r1.do_fetch.sigdata.7c048c18222b16ff0bcee2000ef648b1
+ </literallayout>
+ For tasks that are accelerated through the shared state
+ (<link linkend='shared-state-cache'>sstate</link>)
+ cache, an additional <filename>siginfo</filename> file is
+ written into
+ <link linkend='var-SSTATE_DIR'><filename>SSTATE_DIR</filename></link>
+ along with the cached task output.
+ The <filename>siginfo</filename> files contain exactly the
+ same information as <filename>sigdata</filename> files.
+ </para></listitem>
+ <listitem><para>
+ Run <filename>bitbake-dumpsigs</filename> on the
+ <filename>sigdata</filename> or
+ <filename>siginfo</filename> file.
+ Here is an example:
+ <literallayout class='monospaced'>
+ $ bitbake-dumpsigs ${BUILDDIR}/tmp/stamps/i586-poky-linux/db/6.0.30-r1.do_fetch.sigdata.7c048c18222b16ff0bcee2000ef648b1
+ </literallayout>
+ In the output of the above command, you will find a line
+ like the following, which lists all the (inferred) variable
+ dependencies for the task.
+ This list also includes indirect dependencies from
+ variables depending on other variables, recursively.
+ <literallayout class='monospaced'>
+ Task dependencies: ['PV', 'SRCREV', 'SRC_URI', 'SRC_URI[md5sum]', 'SRC_URI[sha256sum]', 'base_do_fetch']
+ </literallayout>
+ <note>
+ Functions (e.g. <filename>base_do_fetch</filename>)
+ also count as variable dependencies.
+ These functions in turn depend on the variables they
+ reference.
+ </note>
+ The output of <filename>bitbake-dumpsigs</filename> also includes
+ the value each variable had, a list of dependencies for each
+ variable, and
+ <ulink url='&YOCTO_DOCS_BB_URL;#var-BB_HASHBASE_WHITELIST'><filename>BB_HASHBASE_WHITELIST</filename></ulink>
+ information.
+ </para></listitem>
+ </orderedlist>
+ </para>
+
+ <para>
+ There is also a <filename>bitbake-diffsigs</filename> command for
+ comparing two <filename>siginfo</filename> or
+ <filename>sigdata</filename> files.
+ This command can be helpful when trying to figure out what changed
+ between two versions of a task.
+ If you call <filename>bitbake-diffsigs</filename> with just one
+ file, the command behaves like
+ <filename>bitbake-dumpsigs</filename>.
+ </para>
+
+ <para>
+ You can also use BitBake to dump out the signature construction
+ information without executing tasks by using either of the
+ following BitBake command-line options:
+ <literallayout class='monospaced'>
+ &dash;&dash;dump-signatures=<replaceable>SIGNATURE_HANDLER</replaceable>
+ -S <replaceable>SIGNATURE_HANDLER</replaceable>
+ </literallayout>
+ <note>
+ Two common values for
+ <replaceable>SIGNATURE_HANDLER</replaceable> are "none" and
+ "printdiff", which dump only the signature or compare the
+ dumped signature with the cached one, respectively.
+ </note>
+ Using BitBake with either of these options causes BitBake to dump
+ out <filename>sigdata</filename> files in the
+ <filename>stamps</filename> directory for every task it would have
+ executed instead of building the specified target package.
+ </para>
+ </section>
+
<section id='usingpoky-debugging-taskrunning'>
<title>Running Specific Tasks</title>