| <!DOCTYPE html> |
| <body> |
| <script src="../resources/runner.js"></script> |
| <script> |
| var spec = PerfTestRunner.loadFile("resources/html5.html"); |
| |
| var chunks = []; |
| // The smaller the chunks the more style resolves we do. |
| // Smaller chunk sizes will show more samples in style resolution. |
| // Larger chunk sizes will show more samples in line layout. |
| // Smaller chunk sizes run slower overall, as the per-chunk overhead is high. |
| // Testing on my machine has shown that we need 10-15 chunks before style resolution is always the top sample. |
| var chunkSize = 500000; // 6.09mb / 500k = approx 13 chunks (thus 13 forced layouts/style resolves). |
| var chunkCount = Math.ceil(spec.length / chunkSize); |
| for (var chunkIndex = 0; chunkIndex < chunkCount; chunkIndex++) { |
| var chunk = spec.substring(chunkIndex * chunkSize, chunkSize); |
| chunks.push(chunk); |
| } |
| |
| PerfTestRunner.logInfo("Testing " + spec.length + " byte document in " + chunkCount + " " + chunkSize + " byte chunks."); |
| |
| function loadChunkedSpecIntoIframe(iframe) { |
| // Note: We've inlined the stylesheets in html5.html. Before we did that, it seemed to be |
| // random as to whether style resolution would show up at all in the samples. |
| // Talking with Hyatt and jamesr we believe this may be the ignorePendingStylesheets |
| // logic which is triggered off of a timer which is fired after the load completes. |
| // By inlining the stylesheets we're avoiding this race condition. |
| iframe.sandbox = ''; // Prevent external loads which could cause write() to return before completing the parse. |
| iframe.style.width = "600px"; // Have a reasonable size so we're not line-breaking on every character. |
| iframe.style.height = "800px"; |
| iframe.contentDocument.open(); |
| |
| for (var chunkIndex = 0; chunkIndex < chunks.length; chunkIndex++) { |
| iframe.contentDocument.write(chunks[chunkIndex]); |
| // Note that we won't cause a style resolve until we've encountered the <body> element. |
| // Thus the number of chunks counted above is not exactly equal to the number of style resolves. |
| if (iframe.contentDocument.body) |
| iframe.contentDocument.body.clientHeight; // Force a full layout/style-resolve. |
| } |
| |
| iframe.contentDocument.close(); |
| } |
| |
| // Running from the onload callback just makes the UI nicer as it shows the logs before starting the test. |
| window.onload = function() { |
| // Depending on the chosen chunk size, iterations can take over 60s to run on a fast machine, so we only run 2. |
| PerfTestRunner.measureTime({run: function() { |
| var iframe = document.createElement("iframe"); |
| document.body.appendChild(iframe); |
| loadChunkedSpecIntoIframe(iframe); |
| document.body.removeChild(iframe); |
| }, runCount: 2}); |
| } |
| |
| </script> |
| </body> |
