<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd"> <html> <head> <meta name="robots" content="index,nofollow"> <title>ProfilingAllocation - MLton Standard ML Compiler (SML Compiler)</title> <link rel="stylesheet" type="text/css" charset="iso-8859-1" media="all" href="common.css"> <link rel="stylesheet" type="text/css" charset="iso-8859-1" media="screen" href="screen.css"> <link rel="stylesheet" type="text/css" charset="iso-8859-1" media="print" href="print.css"> <link rel="Start" href="Home"> </head> <body lang="en" dir="ltr"> <script src="http://www.google-analytics.com/urchin.js" type="text/javascript"> </script> <script type="text/javascript"> _uacct = "UA-833377-1"; urchinTracker(); </script> <table bgcolor = lightblue cellspacing = 0 style = "border: 0px;" width = 100%> <tr> <td style = " border: 0px; color: darkblue; font-size: 150%; text-align: left;"> <a class = mltona href="Home">MLton MLTONWIKIVERSION</a> <td style = " border: 0px; font-size: 150%; text-align: center; width: 50%;"> ProfilingAllocation <td style = " border: 0px; text-align: right;"> <table cellspacing = 0 style = "border: 0px"> <tr style = "vertical-align: middle;"> </table> <tr style = "background-color: white;"> <td colspan = 3 style = " border: 0px; font-size:70%; text-align: right;"> <a href = "Home">Home</a> <a href = "TitleIndex">Index</a> </table> <div id="content" lang="en" dir="ltr"> With MLton and <tt>mlprof</tt>, you can <a href="Profiling">profile</a> your program to find out how many bytes each function allocates. To do so, compile your program with <tt>-profile alloc</tt>. For example, suppose that <tt>list-rev.sml</tt> is the following. <p> <pre class=code><B><FONT COLOR="#A020F0">fun</FONT></B> append (l1, l2) = <B><FONT COLOR="#A020F0">case</FONT></B> l1 <B><FONT COLOR="#A020F0">of</FONT></B> [] => l2 | x :: l1 => x :: append (l1, l2) <B><FONT COLOR="#A020F0">fun</FONT></B> rev l = <B><FONT COLOR="#A020F0">case</FONT></B> l <B><FONT COLOR="#A020F0">of</FONT></B> [] => [] | x :: l => append (rev l, [x]) <B><FONT COLOR="#A020F0">val</FONT></B> l = List.tabulate (<B><FONT COLOR="#5F9EA0">1000</FONT></B>, <B><FONT COLOR="#A020F0">fn</FONT></B> i => i) <B><FONT COLOR="#A020F0">val</FONT></B> _ = <B><FONT COLOR="#5F9EA0">1</FONT></B> + hd (rev l) </PRE> </p> <p> Compile and run <tt>list-rev</tt> as follows. </p> <pre>% mlton -profile alloc list-rev.sml % ./list-rev % mlprof -show-line true list-rev mlmon.out 6,030,136 bytes allocated (108,336 bytes by GC) function cur ----------------------- ----- append list-rev.sml: 1 97.6% <gc> 1.8% <main> 0.4% rev list-rev.sml: 6 0.2% </pre><p> The data shows that most of the allocation is done by the <tt>append</tt> function defined on line 1 of <tt>list-rev.sml</tt>. The table also shows how special functions like <tt>gc</tt> and <tt>main</tt> are handled: they are printed with surrounding brackets. C functions are displayed similarly. In this example, the allocation done by the garbage collector is due to stack growth, which is usually the case. </p> <p> The run-time performance impact of allocation profiling is noticeable, because it inserts additional C calls for object allocation. </p> <p> Compile with <tt>-profile alloc -profile-branch true</tt> to find out how much allocation is done in each branch of a function; see <a href="ProfilingCounts">ProfilingCounts</a> for more details on <tt>-profile-branch</tt>. </p> </div> <p> <hr> Last edited on 2006-11-02 17:51:52 by <span title="76.16.241.4"><a href="MatthewFluet">MatthewFluet</a></span>. </body></html>