HCoop / hcoop / debian / mlton.git / blame
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| 5 | <meta name="generator" content="AsciiDoc 8.6.9">\r | |
| 6 | <title>ProfilingCounts</title>\r | |
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| 19 | <body class="article">\r | |
| 20 | <div id="banner">\r | |
| 21 | <div id="banner-home">\r | |
| 22 | <a href="./Home">MLton 20180207</a>\r | |
| 23 | </div>\r | |
| 24 | </div>\r | |
| 25 | <div id="header">\r | |
| 26 | <h1>ProfilingCounts</h1>\r | |
| 27 | </div>\r | |
| 28 | <div id="content">\r | |
| 29 | <div id="preamble">\r | |
| 30 | <div class="sectionbody">\r | |
| 31 | <div class="paragraph"><p>With MLton and <span class="monospaced">mlprof</span>, you can <a href="Profiling">profile</a> your program to\r | |
| 32 | find out how many times each function is called and how many times\r | |
| 33 | each branch is taken. To do so, compile your program with\r | |
| 34 | <span class="monospaced">-profile count -profile-branch true</span>. For example, suppose that\r | |
| 35 | <span class="monospaced">tak.sml</span> contains the following.</p></div>\r | |
| 36 | <div class="listingblock">\r | |
| 37 | <div class="content"><div class="highlight"><pre><span class="k">structure</span><span class="w"> </span><span class="n">Tak</span><span class="w"> </span><span class="p">=</span><span class="w"></span>\r | |
| 38 | <span class="w"> </span><span class="k">struct</span><span class="w"></span>\r | |
| 39 | <span class="w"> </span><span class="k">fun</span><span class="w"> </span><span class="n">tak1</span><span class="w"> </span><span class="p">(</span><span class="n">x</span><span class="p">,</span><span class="w"> </span><span class="n">y</span><span class="p">,</span><span class="w"> </span><span class="n">z</span><span class="p">)</span><span class="w"> </span><span class="p">=</span><span class="w"></span>\r | |
| 40 | <span class="w"> </span><span class="k">let</span><span class="w"></span>\r | |
| 41 | <span class="w"> </span><span class="k">fun</span><span class="w"> </span><span class="n">tak2</span><span class="w"> </span><span class="p">(</span><span class="n">x</span><span class="p">,</span><span class="w"> </span><span class="n">y</span><span class="p">,</span><span class="w"> </span><span class="n">z</span><span class="p">)</span><span class="w"> </span><span class="p">=</span><span class="w"></span>\r | |
| 42 | <span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="n">y</span><span class="w"> </span><span class="n">>=</span><span class="w"> </span><span class="n">x</span><span class="w"></span>\r | |
| 43 | <span class="w"> </span><span class="k">then</span><span class="w"> </span><span class="n">z</span><span class="w"></span>\r | |
| 44 | <span class="w"> </span><span class="k">else</span><span class="w"></span>\r | |
| 45 | <span class="w"> </span><span class="n">tak1</span><span class="w"> </span><span class="p">(</span><span class="n">tak2</span><span class="w"> </span><span class="p">(</span><span class="n">x</span><span class="w"> </span><span class="n">-</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="n">y</span><span class="p">,</span><span class="w"> </span><span class="n">z</span><span class="p">),</span><span class="w"></span>\r | |
| 46 | <span class="w"> </span><span class="n">tak2</span><span class="w"> </span><span class="p">(</span><span class="n">y</span><span class="w"> </span><span class="n">-</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="n">z</span><span class="p">,</span><span class="w"> </span><span class="n">x</span><span class="p">),</span><span class="w"></span>\r | |
| 47 | <span class="w"> </span><span class="n">tak2</span><span class="w"> </span><span class="p">(</span><span class="n">z</span><span class="w"> </span><span class="n">-</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="n">x</span><span class="p">,</span><span class="w"> </span><span class="n">y</span><span class="p">))</span><span class="w"></span>\r | |
| 48 | <span class="w"> </span><span class="k">in</span><span class="w"></span>\r | |
| 49 | <span class="w"> </span><span class="k">if</span><span class="w"> </span><span class="n">y</span><span class="w"> </span><span class="n">>=</span><span class="w"> </span><span class="n">x</span><span class="w"></span>\r | |
| 50 | <span class="w"> </span><span class="k">then</span><span class="w"> </span><span class="n">z</span><span class="w"></span>\r | |
| 51 | <span class="w"> </span><span class="k">else</span><span class="w"></span>\r | |
| 52 | <span class="w"> </span><span class="n">tak1</span><span class="w"> </span><span class="p">(</span><span class="n">tak2</span><span class="w"> </span><span class="p">(</span><span class="n">x</span><span class="w"> </span><span class="n">-</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="n">y</span><span class="p">,</span><span class="w"> </span><span class="n">z</span><span class="p">),</span><span class="w"></span>\r | |
| 53 | <span class="w"> </span><span class="n">tak2</span><span class="w"> </span><span class="p">(</span><span class="n">y</span><span class="w"> </span><span class="n">-</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="n">z</span><span class="p">,</span><span class="w"> </span><span class="n">x</span><span class="p">),</span><span class="w"></span>\r | |
| 54 | <span class="w"> </span><span class="n">tak2</span><span class="w"> </span><span class="p">(</span><span class="n">z</span><span class="w"> </span><span class="n">-</span><span class="w"> </span><span class="mi">1</span><span class="p">,</span><span class="w"> </span><span class="n">x</span><span class="p">,</span><span class="w"> </span><span class="n">y</span><span class="p">))</span><span class="w"></span>\r | |
| 55 | <span class="w"> </span><span class="k">end</span><span class="w"></span>\r | |
| 56 | <span class="w"> </span><span class="k">end</span><span class="w"></span>\r | |
| 57 | \r | |
| 58 | <span class="k">val</span><span class="w"> </span><span class="k">rec</span><span class="w"> </span><span class="n">f</span><span class="w"> </span><span class="p">=</span><span class="w"></span>\r | |
| 59 | <span class="w"> </span><span class="k">fn</span><span class="w"> </span><span class="mi">0</span><span class="w"> </span><span class="p">=></span><span class="w"> </span><span class="p">()</span><span class="w"></span>\r | |
| 60 | <span class="w"> </span><span class="p">|</span><span class="w"> </span><span class="mi">~1</span><span class="w"> </span><span class="p">=></span><span class="w"> </span><span class="n">print</span><span class="w"> </span><span class="s">"this branch is not taken</span><span class="se">\n</span><span class="s">"</span><span class="w"></span>\r | |
| 61 | <span class="w"> </span><span class="p">|</span><span class="w"> </span><span class="n">n</span><span class="w"> </span><span class="p">=></span><span class="w"> </span><span class="p">(</span><span class="n">Tak</span><span class="p">.</span><span class="n">tak1</span><span class="w"> </span><span class="p">(</span><span class="mi">18</span><span class="p">,</span><span class="w"> </span><span class="mi">12</span><span class="p">,</span><span class="w"> </span><span class="mi">6</span><span class="p">)</span><span class="w"> </span><span class="p">;</span><span class="w"> </span><span class="n">f</span><span class="w"> </span><span class="p">(</span><span class="n">n-</span><span class="mi">1</span><span class="p">))</span><span class="w"></span>\r | |
| 62 | \r | |
| 63 | <span class="k">val</span><span class="w"> </span><span class="p">_</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="n">f</span><span class="w"> </span><span class="mi">5000</span><span class="w"></span>\r | |
| 64 | \r | |
| 65 | <span class="k">fun</span><span class="w"> </span><span class="n">uncalled</span><span class="w"> </span><span class="p">()</span><span class="w"> </span><span class="p">=</span><span class="w"> </span><span class="p">()</span><span class="w"></span>\r | |
| 66 | </pre></div></div></div>\r | |
| 67 | <div class="paragraph"><p>Compile with count profiling and run the program.</p></div>\r | |
| 68 | <div class="listingblock">\r | |
| 69 | <div class="content monospaced">\r | |
| 70 | <pre>% mlton -profile count -profile-branch true tak.sml\r | |
| 71 | % ./tak</pre>\r | |
| 72 | </div></div>\r | |
| 73 | <div class="paragraph"><p>Display the profiling data, along with raw counts and file positions.</p></div>\r | |
| 74 | <div class="listingblock">\r | |
| 75 | <div class="content monospaced">\r | |
| 76 | <pre>% mlprof -raw true -show-line true tak mlmon.out\r | |
| 77 | 623,610,002 ticks\r | |
| 78 | function cur raw\r | |
| 79 | --------------------------------- ----- -------------\r | |
| 80 | Tak.tak1.tak2 tak.sml: 5 38.2% (238,530,000)\r | |
| 81 | Tak.tak1.tak2.<true> tak.sml: 7 27.5% (171,510,000)\r | |
| 82 | Tak.tak1 tak.sml: 3 10.7% (67,025,000)\r | |
| 83 | Tak.tak1.<true> tak.sml: 14 10.7% (67,025,000)\r | |
| 84 | Tak.tak1.tak2.<false> tak.sml: 9 10.7% (67,020,000)\r | |
| 85 | Tak.tak1.<false> tak.sml: 16 2.0% (12,490,000)\r | |
| 86 | f tak.sml: 23 0.0% (5,001)\r | |
| 87 | f.<branch> tak.sml: 25 0.0% (5,000)\r | |
| 88 | f.<branch> tak.sml: 23 0.0% (1)\r | |
| 89 | uncalled tak.sml: 29 0.0% (0)\r | |
| 90 | f.<branch> tak.sml: 24 0.0% (0)</pre>\r | |
| 91 | </div></div>\r | |
| 92 | <div class="paragraph"><p>Branches are displayed with lexical nesting followed by <span class="monospaced"><branch></span>\r | |
| 93 | where the function name would normally be, or <span class="monospaced"><true></span> or <span class="monospaced"><false></span>\r | |
| 94 | for if-expressions. It is best to run <span class="monospaced">mlprof</span> with <span class="monospaced">-show-line true</span>\r | |
| 95 | to help identify the branch.</p></div>\r | |
| 96 | <div class="paragraph"><p>One use of <span class="monospaced">-profile count</span> is as a code-coverage tool, to help find\r | |
| 97 | code in your program that hasn’t been tested. For this reason,\r | |
| 98 | <span class="monospaced">mlprof</span> displays functions and branches even if they have a count of\r | |
| 99 | zero. As the above output shows, the branch on line 24 was never\r | |
| 100 | taken and the function defined on line 29 was never called. To see\r | |
| 101 | zero counts, it is best to run <span class="monospaced">mlprof</span> with <span class="monospaced">-raw true</span>, since some\r | |
| 102 | code (e.g. the branch on line 23 above) will show up with <span class="monospaced">0.0%</span> but\r | |
| 103 | may still have been executed and hence have a nonzero raw count.</p></div>\r | |
| 104 | </div>\r | |
| 105 | </div>\r | |
| 106 | </div>\r | |
| 107 | <div id="footnotes"><hr></div>\r | |
| 108 | <div id="footer">\r | |
| 109 | <div id="footer-text">\r | |
| 110 | </div>\r | |
| 111 | <div id="footer-badges">\r | |
| 112 | </div>\r | |
| 113 | </div>\r | |
| 114 | </body>\r | |
| 115 | </html>\r |