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<title>Debugging with GDB: Branch Trace Configuration Format</title>

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<a name="Branch-Trace-Configuration-Format"></a>
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<p>
Previous: <a href="Branch-Trace-Format.html#Branch-Trace-Format" accesskey="p" rel="previous">Branch Trace Format</a>, Up: <a href="Remote-Protocol.html#Remote-Protocol" accesskey="u" rel="up">Remote Protocol</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Concept-Index.html#Concept-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Branch-Trace-Configuration-Format-1"></a>
<h3 class="section">E.20 Branch Trace Configuration Format</h3>
<a name="index-branch-trace-configuration-format"></a>

<p>For each inferior thread, <small>GDB</small> can obtain the branch trace
configuration using the &lsquo;<samp>qXfer:btrace-conf:read</samp>&rsquo;
(see <a href="General-Query-Packets.html#qXfer-btrace_002dconf-read">qXfer btrace-conf read</a>) packet.
</p>
<p>The configuration describes the branch trace format and configuration
settings for that format.  The following information is described:
</p>
<dl compact="compact">
<dt><code>bts</code></dt>
<dd><p>This thread uses the <em>Branch Trace Store</em> (<acronym>BTS</acronym>) format.
</p><dl compact="compact">
<dt><code>size</code></dt>
<dd><p>The size of the <acronym>BTS</acronym> ring buffer in bytes.
</p></dd>
</dl>
</dd>
<dt><code>pt</code></dt>
<dd><p>This thread uses the <em>Intel Processor Trace</em> (<acronym>Intel
PT</acronym>) format.
</p><dl compact="compact">
<dt><code>size</code></dt>
<dd><p>The size of the <acronym>Intel PT</acronym> ring buffer in bytes.
</p></dd>
</dl>
</dd>
</dl>

<p><small>GDB</small> must be linked with the Expat library to support XML
branch trace configuration discovery.  See <a href="Requirements.html#Expat">Expat</a>.
</p>
<p>The formal DTD for the branch trace configuration format is given below:
</p>
<div class="smallexample">
<pre class="smallexample">&lt;!ELEMENT btrace-conf	(bts?, pt?)&gt;
&lt;!ATTLIST btrace-conf	version	CDATA	#FIXED &quot;1.0&quot;&gt;

&lt;!ELEMENT bts	EMPTY&gt;
&lt;!ATTLIST bts	size	CDATA	#IMPLIED&gt;

&lt;!ELEMENT pt	EMPTY&gt;
&lt;!ATTLIST pt	size	CDATA	#IMPLIED&gt;
</pre></div>


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