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<title>Using as: i386-LWP</title>

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<a name="i386_002dLWP"></a>
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Next: <a href="i386_002dBMI.html#i386_002dBMI" accesskey="n" rel="next">i386-BMI</a>, Previous: <a href="i386_002dSIMD.html#i386_002dSIMD" accesskey="p" rel="prev">i386-SIMD</a>, Up: <a href="i386_002dDependent.html#i386_002dDependent" accesskey="u" rel="up">i386-Dependent</a> &nbsp; [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="AS-Index.html#AS-Index" title="Index" rel="index">Index</a>]</p>
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<a name="AMD_0027s-Lightweight-Profiling-Instructions"></a>
<h4 class="subsection">9.15.11 AMD&rsquo;s Lightweight Profiling Instructions</h4>

<a name="index-LWP_002c-i386"></a>
<a name="index-LWP_002c-x86_002d64"></a>

<p><code>as</code> supports AMD&rsquo;s Lightweight Profiling (LWP)
instruction set, available on AMD&rsquo;s Family 15h (Orochi) processors.
</p>
<p>LWP enables applications to collect and manage performance data, and
react to performance events.  The collection of performance data
requires no context switches.  LWP runs in the context of a thread and
so several counters can be used independently across multiple threads.
LWP can be used in both 64-bit and legacy 32-bit modes.
</p>
<p>For detailed information on the LWP instruction set, see the
<cite>AMD Lightweight Profiling Specification</cite> available at
<a href="http://developer.amd.com/cpu/LWP">Lightweight Profiling Specification</a>.
</p>


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