From b3386bc5a3f1e45bb779bc9c977aeb7530f52b6f Mon Sep 17 00:00:00 2001
From: Bjoern Brandenburg <bbb@Serenity.local>
Date: Sat, 19 Jul 2008 14:06:24 +0200
Subject: work on the documentation
made it somewhat more pretty
---
gfx/setsched.png | Bin 0 -> 14816 bytes
inc/format.css | 31 ++++++---
index2.html | 192 +++++++++++++++++++++++++++++--------------------------
3 files changed, 123 insertions(+), 100 deletions(-)
create mode 100644 gfx/setsched.png
diff --git a/gfx/setsched.png b/gfx/setsched.png
new file mode 100644
index 0000000..e90c62b
Binary files /dev/null and b/gfx/setsched.png differ
diff --git a/inc/format.css b/inc/format.css
index 3cf2edb..1de7be0 100644
--- a/inc/format.css
+++ b/inc/format.css
@@ -15,7 +15,6 @@ html {
body {
- background-image : url('gfx/corner.png');
background-position : top right;
background-repeat : no-repeat;
@@ -34,6 +33,16 @@ img {
border: 0px;
}
+h4 {
+ font-style: italic;
+ margin: 0;
+ padding: 0;
+}
+
+.release {
+ margin-left: 0.5in;
+}
+
p {
font-size: 12pt;
}
@@ -169,7 +178,7 @@ h1 {
}
h2 {
- font-size: 13pt;
+ font: italic bold 18pt Georgia, "Times New Roman", Times, serif;
}
@@ -186,6 +195,12 @@ h3 {
margin-bottom: 0.1cm;
}
+.relname {
+ color: #eb4f0c;
+ margin-left: 0.25in;
+ font: italic bold 16pt Georgia, "Times New Roman", Times, serif;
+}
+
.itext {
margin-bottom: 0cm;
margin-left: 0.6cm;
@@ -214,14 +229,14 @@ h3 {
margin-left: 0.5cm;
margin-right: 0.5cm;
padding: 0.2cm;
- font-family: Courier New, Courier, monospace;
- font-size: 10pt;
- font-weight: bold;
background-color: #000000;
color: #cccccc;
- border-color: #00C400;
- border-width: 1px;
- border-style: solid;
+ border: 2px solid #eb4f0c;
+ font: bold 10pt "Courier New", Courier, mono;
+}
+
+.qa {
+ margin-top: 0;
}
.flushright {
diff --git a/index2.html b/index2.html
index 883f9ef..db9ebe4 100644
--- a/index2.html
+++ b/index2.html
@@ -53,13 +53,13 @@
</ul>
<p>
</p>
- <p>Earlier versions (2007.1 — 2007.3), which were based on Linux 2.6.20
- and supported additional scheduling policies, are discussed
+ <p>Earlier versions (2007.1 — 2007.3), which are based on Linux 2.6.20
+ and support additional scheduling policies, are discussed
on a separate page dedicated to the <a href="litmus2007.html">LITMUS<sup>RT</sup> 2007 series</a>.
</p>
<p class="nobottommargin">
The first version of LITMUS<sup>RT</sup>, which was implemented in Spring 2006,
- was based on Linux 2.6.9 and never publicly released.
+ is based on Linux 2.6.9.
</div>
<h2 id="support">Support</h2>
@@ -91,7 +91,7 @@
</li>
</ul>
<p>
- (The current version of LITMUS<sup>RT</sup> is based on the <a href="litmus2007.html">2007 series</a>, which had <a href="litmus2007.html#collaborators">additional contributors</a>.)
+ (<a href="litmus2007.html#collaborators">Additional contributors</a> contributed to earlier versions of LITMUS<sup>RT</sup>.)
</p>
</div>
@@ -101,45 +101,49 @@
<ol class="nomargin">
+ <li>
+ <p>
+ B. Brandenburg and J. Anderson,
+ “A Comparison of the M-PCP, D-PCP, and FMLP on LITMUS<sup>RT</sup>”, in submission, July 2008.
+ <a href="http://www.cs.unc.edu/~anderson/papers/opodis08.ps">Postscript</a>. <a href="http://www.cs.unc.edu/~anderson/papers/opodis08.pdf">PDF</a>.
+ </p>
+ </li>
<li>
+ <p>
B. Brandenburg, J. Calandrino, and J. Anderson,
“On the Scalability of Real-Time Scheduling Algorithms on Multicore Platforms: A Case Study”, in submission, May 2008.
<a href="http://www.cs.unc.edu/~anderson/papers/rtss08b.ps">Postscript</a>. <a href="http://www.cs.unc.edu/~anderson/papers/rtss08b.pdf">PDF</a>.
+ </p>
</li>
<li>
- B. Brandenburg and J. Anderson,
- “A Comparison of the M-PCP, D-PCP, and FMLP on LITMUS<sup>RT</sup>”, in submission, April 2008.
- <a href="http://www.cs.unc.edu/~anderson/papers/emsoft08.ps">Postscript</a>. <a href="http://www.cs.unc.edu/~anderson/papers/emsoft08.pdf">PDF</a>.
- </li>
-
- <li>
+ <p>
B. Brandenburg and J. Anderson,
“An Implementation of the PCP, SRP, D-PCP, M-PCP,
and FMLP Real-Time Synchronization Protocols in LITMUS<sup>RT</sup>”,
- <cite>Proceedings of the 14th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications</cite>, to appear, 2008.
+ <cite>Proceedings of the 14th IEEE International Conference on Embedded and Real-Time Computing Systems and Applications</cite>, to appear, August 2008.
<a href="http://www.cs.unc.edu/~anderson/papers/rtcsa08.ps">Postscript</a>. <a href="http://www.cs.unc.edu/~anderson/papers/rtcsa08.pdf">PDF</a>.
+ </p>
</li>
<li>
- A. Block, B. Brandenburg<, J. Anderson,
+ <p>
+ A. Block, B. Brandenburg, J. Anderson,
and S. Quint, “An Adaptive Framework for Multiprocessor Real-Time Systems”,
- <cite>Proceedings of the 20th Euromicro Conference on Real-Time Systems</cite>, to appear, 2008.
+ <cite>Proceedings of the 20th Euromicro Conference on Real-Time Systems</cite>, pp. 23-33, July 2008.
<a href="http://www.cs.unc.edu/~anderson/papers/ecrts08b.ps">Postscript</a>. <a href="http://www.cs.unc.edu/~anderson/papers/ecrts08b.pdf">PDF</a>.
-
+ </p>
</li>
<li>
+ <p>
B. Brandenburg, J. Calandrino, A. Block,
H. Leontyev, and J. Anderson, “Real-Time Synchronization
on Multiprocessors: To Block or Not to Block, to Suspend or
Spin?”, <cite> Proceedings of the 14th IEEE Real-Time and Embedded
Technology and Applications Symposium</cite>, pp. 342-353, April 2008.
<a href="http://www.cs.unc.edu/~anderson/papers/rtas08.ps">Postscript</a>. <a href="http://www.cs.unc.edu/~anderson/papers/rtas08.pdf">PDF</a>.
- </li>
-
-
<p>
Extended version, including all graphs:
<a href="http://www.cs.unc.edu/~anderson/papers/rtas08along.ps">Postscript</a>,
@@ -161,7 +165,7 @@ Technology and Applications Symposium</cite>, pp. 342-353, April 2008.
<p>
B. Brandenburg and J. Anderson, "Integrating Hard/Soft Real-Time Tasks
and Best-Effort Jobs on Multiprocessors", <cite> Proceedings of the 19th Euromicro
- Conference on Real-Time Systems</cite>, July 2007, to appear.
+ Conference on Real-Time Systems</cite>, pp. 61-70, July 2007.
<a href="http://www.cs.unc.edu/~anderson/papers/ecrts07b.ps">Postscript</a>,
<a href="http://www.cs.unc.edu/~anderson/papers/ecrts07b.pdf">PDF</a>.
</p>
@@ -196,13 +200,13 @@ Technology and Applications Symposium</cite>, pp. 342-353, April 2008.
<span class="src">liblitmus</span>, the user-space API for real-time tasks.
</p>
+ <h3 class="relname">LITMUS<sup>RT</sup> 2008.1</h3>
+ <div class="release">
+ <p>
+ Based on Linux 2.6.24. Released in July 2008.
+ </p>
+ <h4>Files:</h4>
<ul>
- <li>
- 2008.1 (July 2008)<br/>
- Based on Linux 2.6.24. (see <a href="#install">Section Install</a>
- below) <br/>
- Files:
- <ul>
<li>
<a href="download/2008.1/litmus-rt-2008.1.patch">litmus-rt-2008.1.patch</a>
</li>
@@ -211,10 +215,9 @@ Technology and Applications Symposium</cite>, pp. 342-353, April 2008.
</li>
<li><a href="download/2008.1/SHA256SUMS">SHA256 check sums</a>
</li>
- </ul>
- </li>
- <li>
- Major changes (compared to LITMUS<sup>RT</sup> 2007.3):
+ </ul>
+
+ <h4>Major changes (since LITMUS<sup>RT</sup> 2007.3):</h4>
<ul>
<li>LITMUS<sup>RT</sup> was ported to Linux 2.6.24.
</li>
@@ -235,6 +238,7 @@ Technology and Applications Symposium</cite>, pp. 342-353, April 2008.
</ul>
</li>
</ul>
+ </div>
<p>
Please note that the current implementation is a <em>prototype</em> with
@@ -255,19 +259,19 @@ Technology and Applications Symposium</cite>, pp. 342-353, April 2008.
<h2 id="install">Installation</h2>
<div class="box">
<p class="notopmargin">
- The current release of LITMUS<sup>RT</sup>, version 2007.2, consists of an
+ The current release of LITMUS<sup>RT</sup> consists of an
extension of the Linux kernel that adds support for the sporadic task
model, a scheduler plugin infrastructure, and some scheduler plugins, as
- well as two user-space libraries that provide the LITMUS<sup>RT</sup>
+ well as a user-space library that provides the LITMUS<sup>RT</sup>
real-time API. Note, that the current implementation only works on the
- Intel x86 architecture.
+ Intel x86-32 and sparc64 architectures.
</p>
<h3>Patching the Kernel</h3>
<p class="notopmargin">
The extension to the Linux kernel is released as a patch against Linux
- 2.6.20. To install the LITMUS<sup>RT</sup> kernel, first <a
- href="http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.20.tar.bz2">download the Linux
- kernel 2.6.20</a> and untar it in a directory of your choice (hereafter
+ 2.6.24. To install the LITMUS<sup>RT</sup> kernel, first <a
+ href="http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.24.tar.bz2">download the Linux
+ kernel 2.6.24</a> and untar it in a directory of your choice (hereafter
referred to as <span class="src">$DIR</span>). Second, apply the
LITMUS<sup>RT</sup> patch (see <a href="#download">Section Download</a>)
and configure, compile, and install the kernel as usual. The patch is <span
@@ -277,78 +281,46 @@ Technology and Applications Symposium</cite>, pp. 342-353, April 2008.
</p>
<pre class="shell">
cd $DIR
-# get Linux 2.6.20
-wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.20.tar.bz2
-tar xjf linux-2.6.20.tar.bz2
-wget http://www.cs.unc.edu/~anderson/litmus-rt/download/2007.3/litmus-rt-2007.3.patch
-mv linux-2.6.20 litmus-rt
+# get Linux 2.6.24
+wget http://www.kernel.org/pub/linux/kernel/v2.6/linux-2.6.24.tar.bz2
+tar xjf linux-2.6.24.tar.bz2
+wget http://www.cs.unc.edu/~anderson/litmus-rt/download/2008.1/litmus-rt-2008.1.patch
+mv linux-2.6.24 litmus2008
# apply the LITMUS RT patch
-cd litmus-rt
-patch -p1 < ../litmus-rt-2007.3.patch
+cd litmus2008
+patch -p1 < ../litmus-rt-2008.1.patch
# create a working kernel configuration with HZ=1000
-make gconfig
+make menuconfig
# compile the kernel
make bzImage
make modules
# proceed to install kernel, build initrd, etc.
...
</pre>
- <p>
- After the kernel has been compiled and installed, the boot-loader must be
- configured to load the desired real-time scheduler plugin at boot time (run
- time selection of the real-time scheduler is currently not supported). The
- real-time scheduler plugin is selected with the <span
- class="src">rtsched</span> kernel parameter.
- </p>
-<pre class="shell">
-rtsched= {linux, pfair, part_edf, global_edf,
- global_edf_np, edf_hsb, gsn_edf, psn_edf, adaptive}
-</pre>
- <p>
- For example, on our test machine, we use the
- following GRUB entry:
- </p>
-
-<pre class="shell">
-title Kernel 2.6.20-LITMUSRT
-root (hd0,5)
-kernel /boot/vmlinuz-2.6.20-LITMUSRT root=/dev/sda6 ro vga=791 rtsched=gsn_edf
-initrd /boot/kernel-2.6.20-LITMUSRT.img
-</pre>
+ <p>
+ When configuring the kernel, note that there is a menu (at the very end of the list)
+ with LITMUS<sup>RT</sup>-specific configuration options.
+ </p>
<h3>Libraries</h3>
<p class="notopmargin">
- The two user-space libraries, <span class="src">liblitmus</span> and <span
- class="src">libso</span>, provide their own makefiles and thus are easy to
- compile. The kernel interface for real-time tasks is provided by <span
- class="src">liblitmus</span>, which can be compiled as follows:
+ The user-space library for real-time tasks, <span class="src">liblitmus</span>,
+ depends on the LITMUS<sup>RT</sup> kernel kernel and provides its own makefile.
+ In order to compile <span class="src">liblitmus</span>, you need to adjust the
+ variable <span class="src">KERNEL_DIR</span> in the Makfile to point to your
+ copy of the kernel.
</p>
<pre class="shell">
cd $DIR
-wget http://www.cs.unc.edu/~anderson/litmus-rt/download/2007.3/liblitmus-2007.3.tgz
-tar xzf liblitmus-2007.3.tgz
+wget http://www.cs.unc.edu/~anderson/litmus-rt/download/2008.1/liblitmus-2008.1.tgz
+tar xzf liblitmus-2008.1.tgz
cd liblitmus
+# change KERNEL_DIR in Makefile to point to the kernel source
make
-</pre>
- <p>
- The second library, <span class="src">libso</span>, provides shared object
- and synchronization support for real-time tasks. It depends on <span
- class="src">liblitmus</span> and must be installed in "parallel"
- (they must have the same parent directory). The following commands will
- obtain and compile <span class="src">libso</span>, including the test programs:
- </p>
-<pre class="shell">
-cd $DIR
-wget http://www.cs.unc.edu/~anderson/litmus-rt/download/2007.3/libso-2007.3.tgz
-tar xzf libso-2007.3.tgz
-cd libso
-make
-make tests
</pre>
<p class="nobottommargin">
Please refer to the <a href="#doc">documentation</a> on how to use the LITMUS<sup>RT</sup>
- real-time API as provided by <span class="src">libso</span> and
- <span class="src">liblitmus</span>.
+ real-time API as provided by <span class="src">liblitmus</span>.
</p>
</div>
@@ -358,18 +330,56 @@ make tests
<div class="box">
<p class="notopmargin">
- Most of the documentation has yet to be written. To get an overview of
+ Unfortunately, most of the documentation has yet to be written. To get an overview of
the architecture of the kernel extension, we recommend reading the paper
<a href="http://www.cs.unc.edu/~anderson/papers/rtlws07.pdf">“LITMUS<sup>RT</sup>:
A Status Report”</a>.
</p>
+ <h3>Real-Time Scheduling Policies</h3>
+ <p class="qa">
+ The kernel contains the following real-time scheduling policy implementations:
+ </p>
+ <ul>
+ <li>
+ PFAIR, an implementation of the PD<sup>2</sup> algorithm,
+ </li>
+ <li>
+ PSN-EDF, a partitioned EDF (P-EDF) implementation with support for the real-time synchronization protocol
+ FMLP,
+ </li>
+ <li>
+ GSN-EDF, a global EDF (G-EDF) implementation with support for the real-time synchronization protocol
+ FMLP,
+ </li>
+ <li>
+ C-EDF (Clustered EDF), a hybrid of G-EDF and P-EDF, and
+ </li>
+ <li>
+ Linux, a placeholder policy that disables all real-time functionality added by the LITMUS<sup>RT</sup> patch.
+ </li>
+ </ul>
<p>
+ Only one policy can be active at any time. Initially (<em>i.e.,</em> during boot), the "Linux" policy is active.
+ You can use the tool <span class="src">showsched</span> (part of <span class="src">liblitmus</span>) to display
+ the name of the currently active policy.
+ </p>
+ <h3>Changing the Active Policy</h3>
+ <p class="qa">
+ You can use the tool <span class="src">setsched</span> (part of <span class="src">liblitmus</span>)
+ to select a new plugin at run time.
+ <div align="center">
+ <img class="screenshot" src="gfx/setsched.png" alt="Screen shot of setsched"/>
+ </div>
+ Only root can change the active policy, and only when there are no real-time tasks present.
+ </p>
+ <h3>Writing Real-Time Tasks</h3>
+ <p class="qa">
The user space library that provides the LITMUS<sup>RT</sup> API,
<span class="src">liblitmus</span>, contains two example real-time tasks
(<span class="src">base_task.c</span> and
<span class="src">base_mt_task.c</span>)
that both illustrate how to use the API and provide a skeleton for real-time
- task development. To get started with development, take a look these example
+ task development. To get started with development, please take a look these example
programs.
</p>
<p class="nobottommargin">
@@ -390,9 +400,7 @@ make tests
<p class="nomargin">
Linux is a registered trademark of Linus Torvalds. <br /> The
- LITMUS<sup>RT</sup> logo was designed by <a
- href="http://designs.primevalpress.com">Jasper McChesney</a> of <a
- href="http://designs.primevalpress.com">Primeval Designs</a>. <br />
+ LITMUS<sup>RT</sup> logo was designed by Jasper McChesney of Primeval Designs. <br />
Web design by Björn Brandenburg.
</p>
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