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<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->+
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<!-- This component and the accompanying materials are made available under the terms of the License +
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and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->+
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<!-- Initial Contributors:+
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    Nokia Corporation - initial contribution.+
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Contributors: +
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-->+
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<!DOCTYPE concept+
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  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">+
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<concept id="GUID-BD9F3912-9C8B-5962-BEC7-D5F961335B49" xml:lang="en"><title>Kernel+
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Trace Tool Overview</title><shortdesc>Describes the Kernel Trace tool to obtain trace information. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>+
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<section id="GUID-6DC0934A-BE24-4E13-8603-011BBBBFA8DE"><title>Purpose</title> <p>The+
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trace tool provides a means of extracting trace data from a memory buffer. </p> </section>+
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<section id="GUID-5933F3F4-AE73-4E6D-9E4D-0D5A854F39C3"><title>Required background</title> <p>The+
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kernel trace tool LDD is only a part of the actual kernel trace tool. </p> <p>The+
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actual kernel trace tool consists of the following: </p> <ul>+
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<li id="GUID-1D5857F0-418E-5ECE-BC9F-BF97DF06DAC3"><p><filepath>btracex.ldd</filepath> </p> <p>Used+
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to obtain kernel activity and place it in a buffer that can be seen by user-side+
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applications. </p> </li>+
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<li id="GUID-8C2EA2EA-2A04-51E3-98F3-CBDE01F62CE9"><p>trace filters defined+
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in EUser </p> <p>Used to filter out the trace information that is not required. </p> </li>+
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<li id="GUID-B370EE1C-8CB3-5A9A-AD70-DB591D77BDFC"><p><filepath>btracec.dll</filepath> and <filepath>btracec.lib</filepath> </p> <p>Used+
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to provide an interface for extracting trace data from a memory buffer. </p> </li>+
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</ul> </section>+
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<section id="GUID-A6FB8DB6-5623-401B-8112-1FD0789B1785"><title>Key concepts+
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and terms</title> <dl>+
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<dlentry>+
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<dt>user-side and kernel-side</dt>+
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<dd><p>When an application asks for service from an operating system it is+
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actually making a request for the operating system to carry this out (a state+
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of affairs known as user-side). The request can only be carried out by the+
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operating system (a state of affairs known as kernel-side). </p> <p>This method+
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is used to prevent one process (or thread) from interfering with the internal+
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operation of another. </p> </dd>+
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</dlentry>+
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</dl> </section>+
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<section id="GUID-86FFD675-07A0-4502-9BDE-58A8FCDB5A7F"><title>Architecture</title> <p>The+
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trace tool consists of two parts, a driver on the user-side that captures+
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the required kernel events and writes them to a buffer that be accessed by+
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user-side applications. Then a trace filter, <filepath>btracec.dll</filepath> and <filepath>btrace.lib</filepath> are+
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used as an interface to the trace buffer. </p> </section>+
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<section id="GUID-0932C259-5F05-4F95-B16C-C08D345EE3C2"><title>APIs</title> <table id="GUID-AE6F13C1-B835-5A4E-B834-9515146CAA3C">+
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<tgroup cols="2"><colspec colname="col0"/><colspec colname="col1"/>+
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<thead>+
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<row>+
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<entry>API</entry>+
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<entry>Description</entry>+
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</row>+
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</thead>+
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<tbody>+
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<row>+
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<entry><p> <xref href="GUID-9E859841-E8A3-37D5-9A19-BCAA3C700922.dita"><apiname>RBTrace</apiname></xref>  </p> </entry>+
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<entry><p>Interface to the fast-trace memory buffer. </p> <p> <note> Use btracec.dll+
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and btracec.lib to access this buffer.</note> </p> </entry>+
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</row>+
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</tbody>+
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</tgroup>+
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</table> </section>+
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<section id="GUID-E461A3A5-99E9-49AC-ADF4-ADEEFE524A47"><title>Typical uses</title> <p>The+
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kernel trace tool is intended to be used by developers for obtaining trace+
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information. </p> </section>+
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</conbody><related-links>+
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<link href="GUID-BD9F3912-9C8B-5962-BEC7-D5F961335B49.dita"><linktext>Kernel Trace+
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Tool                 Overview</linktext></link>+
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</related-links></concept>+
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