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<h4 class="subsection">9.15.11 AMD's Lightweight Profiling Instructions</h4>
<p><a name="index-LWP_002c-i386-1141"></a><a name="index-LWP_002c-x86_002d64-1142"></a>
<code>as</code> supports AMD's Lightweight Profiling (LWP)
instruction set, available on AMD's Family 15h (Orochi) processors.
<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>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>.
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