canvas-cacheviz/index.html at master · brk/canvas-cacheviz · GitHub

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<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="content-type" content="text/html; charset=utf-8" />
    <title>Canvas Cache Visualizer</title>
    <link rel="stylesheet" type="text/css" media="screen" href="canvas.css" />

    <script src="http://www.google.com/jsapi"></script>
    <script type="text/javascript">google.load("jquery", 1);</script>

    <script type="text/javascript" src="store.js"></script>
    <script type="text/javascript" src="cache.js"></script>
    <script type="text/javascript" src="main.js"></script>
  </head>
  <body onload="main();">
      <a id="gitsrc" style="float: right;" href="http://github.com/brk/canvas-cacheviz">source repository</a>
            <span class="step-num">1: </span>
            <span class="step-desc">Choose From Available Snippets:</span>
        <h3>(click to load snippet)</h3>
<ul id="snippet-list">
  <li><input type="button" class="title" value="// Sequential access by rows"></input>
  <pre>
function (a, w, h) {
  for (i = 0; i &lt; h; i++) {
    for (j = 0; j &lt; w; j++) {
      a.touch(i,j);
    }
  }
}
  </pre></li>
<!-- ====================================================== -->
<li><input type="button" class="title" value="// Sequential access by columns"></input>
  <pre>
function (a, w, h) {
  for (j = 0; j &lt; w; j++) {
    for (i = 0; i &lt; h; i++) {
      a.touch(i,j);
    }
  }
}
  </pre>
  </pre></li>
<!-- ====================================================== -->
  <li><input type="button" class="title" value="// Simple Matrix Transposition"></input>
  <pre>
function (a, w, h) {
  for (i = 0; i &lt; h; i++) {
    for (j = i+1; j &lt; w; j++) {
      a.touch(i,j);
      a.touch(j,i);
    }
  }
}
  </pre>
  </pre></li>
<!-- ====================================================== -->
<li><input type="button" class="title" value="// Cache-Oblivious Matrix Transposition"></input>
  <pre>
function (a, w, h) {
  var transpose_base = function(a, x, y, w, h) {
    for (i = x; i &lt; x+w; i++) {
      for (j = y; j &lt; y+h; j++) {
        if (j &gt;= i) continue;
        /* when iterating over a block that straddles
        the diagonal, only swap the upper triangle */
        a.touch(i,j);
        a.touch(j,i);
      }
    }
  };
  var transpose_block = function(a, x, y, w, h) {
    /* avoid blocks entirely below diagonal */
    if ( (x+w) &lt;= y ) return;
    if (w &lt;= 8 &amp;&amp; h &lt;= 8) {
      transpose_base(a, x, y, w, h); return;
    }
    if (w &gt;= h) {
      var mid = Math.floor(w/2);
      transpose_block(a, x    , y,   mid, h);
      transpose_block(a, x+mid, y, w-mid, h);
    } else {
      var mid = Math.floor(h/2);
      transpose_block(a, x,     y, w,   mid);
      transpose_block(a, x, y+mid, w, h-mid);
    }
  };

  transpose_block(a, 0, 0, w, h);
}
  </pre></li>
</ul>

    <p>In the code below, <kbd>a.touch(i,j)</kbd> indicates array access
    <kbd>a[i][j]</kbd>.</p>
    <textarea rows="14" cols="60" id="code-textarea" class="console">
// Sequential access by rows
function (a, w, h) {
  for (i = 0; i &lt; h; i++) {
    for (j = 0; j &lt; w; j++) {
      a.touch(i,j);
    }
  }
}
    </textarea>
    <br>

    <div id="control-buttons">
      <span class="step-num">2: </span>
      <span class="step-desc">Start Visualizing!</span>
      <br>
      <button id="run-button"     onclick="window.animate = false; run();">Run</button>
      <button id="animate-button" onclick="window.animate = true; run();">Animate</button>
      <button id="draw-cache-button" onclick="window.animate = false; draw_cache_lines();">Draw Cache</button>
    </div>
    <br>

    <span class="step-num">3: </span>
    <span class="step-desc">See Results!</span>
    <table>
      <tr>
        <th>Memory Touches</th>
        <th>Cache Hits (green) / Misses (red)</th>
        <th>TODO</th>
      </tr>
      <tr>
        <td>
          <canvas id="store-canvas"
                  width="256"
                  height="256"
                  ></canvas>
        </td>
        <td>
          <canvas id="cache-canvas"
                  width="256"
                  height="256"
                  ></canvas>
        </td>
        <td>
          <ul>
            <li>jquery slider to control variable animation speeds</li>
            <li>jQuery slider to scale views -- e.g. use 2 or 4 pixels instead of 1</li>
            <li>On Chrome, at least, repeated runs can lead to de-synced animation... odd, but
            mostly harmless</li>
          </ul>
        </td>
      </tr>
      <tr>
        <td>Memory touches are colored by time:<br> black at the start, white at the end</td>
        <td>Each "pixel" is a four-byte element.</td>
        <td></td>
      </tr>
    </table>

    <hr>
    <div id="error" style="margin-bottom:20px;">
    </div>
  </body>
</html>