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| author | Scott Rifenbark <srifenbark@gmail.com> | 2018-01-29 15:18:03 -0800 |
|---|---|---|
| committer | Richard Purdie <richard.purdie@linuxfoundation.org> | 2018-02-14 15:25:29 +0000 |
| commit | ae06e04cd225d2c2147ca355e2dd39b4f6cf6775 (patch) | |
| tree | c920e85262a91e7626279e7dcbbd56a299919f49 /documentation/getting-started/eclipse/html/getting-started/stamp-files-and-the-rerunning-of-tasks.html | |
| parent | ebc7de094881dd8f2450aa4fdf548f2e9c835df1 (diff) | |
| download | poky-ae06e04cd225d2c2147ca355e2dd39b4f6cf6775.tar.gz | |
documentation: Created new "Getting Started" manual.
Creation involved removing the overview-manual and replacing it
with the getting-started manual. All links to the string
"&YOCTO_DOCS_OVERVIEW_URL" had to be replaced with
"&YOCTO_DOCS_GS_URL" across the entire YP manual set. I renamed
files used to create the manual with prefixes suited for the
new manual name, which is "Getting Started With Yocto Project".
The style sheet for the new manual needed updating to display the
new .PNG image for the title page. The mega-manual file had to
be updated to include the files. The mega-manual.sed file had
to be updated to include the new manual and not use the overview
manual.
(From yocto-docs rev: 6c7abf9192390121000f577d6c98f259d290d15d)
Signed-off-by: Scott Rifenbark <srifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Diffstat (limited to 'documentation/getting-started/eclipse/html/getting-started/stamp-files-and-the-rerunning-of-tasks.html')
| -rw-r--r-- | documentation/getting-started/eclipse/html/getting-started/stamp-files-and-the-rerunning-of-tasks.html | 83 |
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| 1 | <html> | ||
| 2 | <head> | ||
| 3 | <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> | ||
| 4 | <title>2.8.5.7. Stamp Files and the Rerunning of Tasks</title> | ||
| 5 | <link rel="stylesheet" type="text/css" href="../book.css"> | ||
| 6 | <meta name="generator" content="DocBook XSL Stylesheets V1.76.1"> | ||
| 7 | <link rel="home" href="index.html" title="Getting Started With Yocto Project"> | ||
| 8 | <link rel="up" href="bitbake-dev-environment.html" title="2.8.5. BitBake"> | ||
| 9 | <link rel="prev" href="sdk-generation-dev-environment.html" title="2.8.5.6. SDK Generation"> | ||
| 10 | <link rel="next" href="setscene-tasks-and-shared-state.html" title="2.8.5.8. Setscene Tasks and Shared State"> | ||
| 11 | </head> | ||
| 12 | <body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><div class="section" title="2.8.5.7. Stamp Files and the Rerunning of Tasks"> | ||
| 13 | <div class="titlepage"><div><div><h4 class="title"> | ||
| 14 | <a name="stamp-files-and-the-rerunning-of-tasks"></a>2.8.5.7. Stamp Files and the Rerunning of Tasks</h4></div></div></div> | ||
| 15 | <p> | ||
| 16 | For each task that completes successfully, BitBake writes a | ||
| 17 | stamp file into the | ||
| 18 | <a class="link" href="../ref-manual/var-STAMPS_DIR.html" target="_self"><code class="filename">STAMPS_DIR</code></a> | ||
| 19 | directory. | ||
| 20 | The beginning of the stamp file's filename is determined by the | ||
| 21 | <a class="link" href="../ref-manual/var-STAMP.html" target="_self"><code class="filename">STAMP</code></a> | ||
| 22 | variable, and the end of the name consists of the task's name | ||
| 23 | and current | ||
| 24 | <a class="link" href="overview-checksums.html" title="3.3.2. Checksums (Signatures)">input checksum</a>. | ||
| 25 | </p> | ||
| 26 | <div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;"> | ||
| 27 | <h3 class="title">Note</h3> | ||
| 28 | This naming scheme assumes that | ||
| 29 | <a class="link" href="../bitbake-user-manual/var-BB_SIGNATURE_HANDLER.html" target="_self"><code class="filename">BB_SIGNATURE_HANDLER</code></a> | ||
| 30 | is "OEBasicHash", which is almost always the case in | ||
| 31 | current OpenEmbedded. | ||
| 32 | </div> | ||
| 33 | <p> | ||
| 34 | To determine if a task needs to be rerun, BitBake checks if a | ||
| 35 | stamp file with a matching input checksum exists for the task. | ||
| 36 | If such a stamp file exists, the task's output is assumed to | ||
| 37 | exist and still be valid. | ||
| 38 | If the file does not exist, the task is rerun. | ||
| 39 | </p> | ||
| 40 | <div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;"> | ||
| 41 | <h3 class="title">Note</h3> | ||
| 42 | <p>The stamp mechanism is more general than the shared | ||
| 43 | state (sstate) cache mechanism described in the | ||
| 44 | "<a class="link" href="setscene-tasks-and-shared-state.html" title="2.8.5.8. Setscene Tasks and Shared State">Setscene Tasks and Shared State</a>" | ||
| 45 | section. | ||
| 46 | BitBake avoids rerunning any task that has a valid | ||
| 47 | stamp file, not just tasks that can be accelerated through | ||
| 48 | the sstate cache.</p> | ||
| 49 | <p>However, you should realize that stamp files only | ||
| 50 | serve as a marker that some work has been done and that | ||
| 51 | these files do not record task output. | ||
| 52 | The actual task output would usually be somewhere in | ||
| 53 | <a class="link" href="../ref-manual/var-TMPDIR.html" target="_self"><code class="filename">TMPDIR</code></a> | ||
| 54 | (e.g. in some recipe's | ||
| 55 | <a class="link" href="../ref-manual/var-WORKDIR.html" target="_self"><code class="filename">WORKDIR</code></a>.) | ||
| 56 | What the sstate cache mechanism adds is a way to cache task | ||
| 57 | output that can then be shared between build machines. | ||
| 58 | </p> | ||
| 59 | </div> | ||
| 60 | <p> | ||
| 61 | Since <code class="filename">STAMPS_DIR</code> is usually a subdirectory | ||
| 62 | of <code class="filename">TMPDIR</code>, removing | ||
| 63 | <code class="filename">TMPDIR</code> will also remove | ||
| 64 | <code class="filename">STAMPS_DIR</code>, which means tasks will | ||
| 65 | properly be rerun to repopulate <code class="filename">TMPDIR</code>. | ||
| 66 | </p> | ||
| 67 | <p> | ||
| 68 | If you want some task to always be considered "out of date", | ||
| 69 | you can mark it with the | ||
| 70 | <a class="link" href="../bitbake-user-manual/variable-flags.html" target="_self"><code class="filename">nostamp</code></a> | ||
| 71 | varflag. | ||
| 72 | If some other task depends on such a task, then that task will | ||
| 73 | also always be considered out of date, which might not be what | ||
| 74 | you want. | ||
| 75 | </p> | ||
| 76 | <p> | ||
| 77 | For details on how to view information about a task's | ||
| 78 | signature, see the | ||
| 79 | "<a class="link" href="../dev-manual/dev-viewing-task-variable-dependencies.html" target="_self">Viewing Task Variable Dependencies</a>" | ||
| 80 | section in the Yocto Project Development Tasks Manual. | ||
| 81 | </p> | ||
| 82 | </div></body> | ||
| 83 | </html> | ||