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+<?xml version="1.0" encoding="utf-8"?>
+<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
+<!-- This component and the accompanying materials are made available under the terms of the License 
+"Eclipse Public License v1.0" which accompanies this distribution, 
+and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
+<!-- Initial Contributors:
+    Nokia Corporation - initial contribution.
+Contributors: 
+-->
+<!DOCTYPE concept
+  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
+<concept id="GUID-3D5974E9-0F6C-4BBE-AD41-C405DC286C09" xml:lang="en"><title>Crazy Scheduler</title><shortdesc>This document describes the crazy scheduler tool.</shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
+<section id="GUID-BB5A11B3-4EEB-4DD1-A9CF-F0D38BC87527"><title>Introduction</title><p>The adding of new functionality to the kernel has meant that Inter-Process
+Communication (IPC) is no longer deterministic.  The crazy scheduler
+is a tool that is designed to simulate the effect of IPC calls occurring
+at any time. With this tool, developers can check that their code
+will still work with the latest version of the kernel.</p><p>Crazy
+scheduler has two modes of operation:</p><ul>
+<li><p>Crazy delays</p></li>
+<li><p>Crazy priorities</p></li>
+</ul><p><note>Both modes of operation should not be enabled simultaneously
+since this could cause the system to deadlock.</note></p><p>Ideally,
+the test cases should be run twice (once with each mode of the crazy
+scheduler).</p> </section>
+<section id="GUID-EE0742D8-4050-4307-BBF9-DE00B4CD9D0B"><title>Crazy
+delay mode</title><p>This mode is used to test the effect of a delay
+in threads moving between states.</p></section>
+<section id="GUID-D104CF5B-22F6-4367-8220-3E213583C014"><title>Crazy
+priority mode</title><p>This mode is used to test the effect of no
+longer being able to rely on thread priority to synchronize IPC calls.
+In this mode, an IPC call can occur at any time. </p></section>
+<section id="GUID-D23075E3-C015-4ECF-A0E2-65553B3506E5"><title>Prerequisites</title><p>Your build should have the crazy scheduler present. It is present
+in the udeb version of a build and is disabled by default.</p></section>
+<section id="GUID-03C46CE1-6ED6-4448-A804-E023D25477E1"><title>Limitations</title><p>Crazy scheduler will only work on the udeb version of a build.
+Crazy scheduler in crazy priority mode does not impact the system
+as heavily as the crazy scheduler in crazy delay mode. Crazy Priority
+mode can only be enabled at ROM time or boot time (for the emulator).
+Do not expect this tool to find all the issues associated with IPC
+and synchronization. The crazy delay mode will slow the system down.</p><p><note>When a build is booting with the crazy scheduler in crazy
+delay mode enabled, the booting process can take a long time. In fact
+it can appear that it has hung. To reduce the boot time, it is advisable
+to do the following:<ul>
+<li><p>Format the user NAND (C:) partition using a regular ROM image
+before booting the build with the crazy scheduler enabled.</p></li>
+</ul>It is advisable to execute the crazy scheduling tests on both
+the emulator and on hardware. </note></p></section>
+<section id="GUID-B7C2FAE4-4DA7-4678-BB9E-788E884BEDC4"><title>How
+to enable the crazy scheduler</title><p>The Crazy scheduler can be
+used on both the emulator and hardware builds.</p></section>
+<section id="GUID-A0B0C64D-5366-47C7-9599-5E528855C36E"><title>Enabling
+for hardware</title><p>If the crazy scheduler is to be executed on
+hardware, then there are two ways to enable it:</p><ul>
+<li><p>Add the parameters -DCRAZYSCHEDDELAY (for the crazy delay)
+or -DCRAZYSCHEDPRIO (for crazy priority) to the buildrom arguments.
+Do not enable both parameters at the same time.</p></li>
+</ul><p>There are other ways of enabling the two modes of the crazy
+scheduler:</p><ul>
+<li><p>To enable the crazy priorities mode, include the following
+line into the relevant iby/oby file:</p><p>CRAZYSCHEDULING(on)</p></li>
+<li><p>To enable the crazy delay mode , include the following line
+into the relevant iby/oby file: </p><p>kerneltrace 0x80000000 0 0x20
+0 0 0 0 0</p></li>
+</ul></section>
+<section id="GUID-EEF30371-BF17-4C14-BC06-8C8C92E514DC"><title>Enabling
+for the emulator</title><p>If the crazy scheduler is to run on the
+emulator, then:</p><ul>
+<li><p>To enable crazy delays, add the following line to the \epoc\data\epoc.ini
+file:</p><p>debugmask2 0x20</p></li>
+<li><p>To enable crazy priorities, add the following line to the \epoc32\data\epoc.ini
+file:</p><p>crazyscheduling on</p></li>
+</ul><p><note>Do not enable both crazy delays and crazy priorities
+on at once.</note></p></section>
+<section id="GUID-1D6341AB-D9F1-4F39-AD93-3DF0B408EE4A"><title>Runtime
+enabling</title><p>The crazy delays can be toggled on or off at runtime.</p><p>To do this, EShell must be running. The following commands can
+be used from within EShell:</p><table id="GUID-B3A9D71D-ED36-4FB4-AEB6-01B4C9AD78CF">
+<tgroup cols="2"><colspec colname="col1"/><colspec colname="col2"/>
+<tbody>
+<row>
+<entry><p><b>Command</b></p></entry>
+<entry><p><b>Description</b></p></entry>
+</row>
+<row>
+<entry><p>trace on 69</p></entry>
+<entry><p>Enable crazy delays</p></entry>
+</row>
+<row>
+<entry><p>trace off 69</p></entry>
+<entry><p>Disable crazy delays</p></entry>
+</row>
+</tbody>
+</tgroup>
+</table><p><note>Crazy priority cannot be toggled on or off at runtime.</note></p></section>
+<section id="GUID-B1284B69-ECCF-4265-A2A6-50C7AC0BD7BB"><title>State
+of the crazy scheduler</title><p>The state of the crazy scheduler
+can be obtained by executing the following in EShell:</p><ul>
+<li><p>sysinfo</p></li>
+</ul><p>The output will tell you which of the crazy scheduler modes
+are enabled or disabled.</p></section>
+<section id="GUID-582EB310-2404-455B-B9F8-59D1367D4E36"><title>How
+to obtain the output from the crazy scheduler</title><p>The crazy
+scheduler does not produce output as such, instead it is expected
+to work in conjunction with other test tools. The only output from
+this tool is whether an application will still work or not.</p></section>
+<section id="GUID-C47E10B3-DA1F-47EE-BAB8-536055580C95"><title>How
+to interpret the output from the crazy scheduler</title><p>As for
+above. </p></section>
+</conbody><related-links>
+<link href="GUID-7FB63DAA-FBFD-4485-919F-5FEFBBC53B97.dita"><linktext>SMP
+Tools Overview</linktext></link>
+</related-links></concept>
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