Measure execution time of code block

gistfile1.aw

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<?php
   $mtime = microtime();
   $mtime = explode(" ",$mtime);
   $mtime = $mtime[1] + $mtime[0];
   $starttime = $mtime;
?>

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<!-- put other code and html in here -->
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<!-- put this code at the bottom of the page -->
<?php
   $mtime = microtime();
   $mtime = explode(" ",$mtime);
   $mtime = $mtime[1] + $mtime[0];
   $endtime = $mtime;
   $totaltime = ($endtime - $starttime);
   echo "Last code block was executed in ".$totaltime." seconds";
?>