Author: ceki Date: Tue May 6 22:23:57 2008 New Revision: 1691 Modified: logback/trunk/logback-site/src/site/pages/manual/profilers.html Log: - ongoing work Modified: logback/trunk/logback-site/src/site/pages/manual/profilers.html ============================================================================== --- logback/trunk/logback-site/src/site/pages/manual/profilers.html (original) +++ logback/trunk/logback-site/src/site/pages/manual/profilers.html Tue May 6 22:23:57 2008 @@ -2,13 +2,13 @@ <html xmlns="http://www.w3.org/1999/xhtml"> <head> <meta http-equiv="content-type" content="text/html; charset=iso-8859-1" /> -<title>Chapter 5: Layouts</title> +<title>Chapter 8: Profilers</title> <link rel="stylesheet" type="text/css" media="screen" href="../css/site.css" /> <link rel="stylesheet" type="text/css" media="print" href="../css/print.css" /> </head> <body> - <script> + <script> prefix='../'; </script> <script src="../templates/header.js"></script> @@ -21,7 +21,7 @@ <div id="content"> <h1>Chapter 8: Profilers</h1> - + <div class="quote"> <p>We should forget about small efficiencies, say about 97% of the time: premature optimization is the root of all evil. @@ -31,7 +31,7 @@ <script src="../templates/creative.js"></script> <script src="../templates/setup.js"></script> - + <h2>What is a profiler?</h2> <p>According to wikipedia, <a @@ -43,30 +43,67 @@ optimize for speed or memory usage. </p> - <p>A logback profiler help the developer gather performance data - by managing one or more stopwatches driven by statements inserted - in the source code. An example, should make the point clearer. + <p>A logback profiler will help the developer to gather + performance data. Essentially, a profiler consists of one or more + stopwatches. Stopwatches are driven (started/stopped) by + statements in the source code. An example, should make the point + clearer. </p> - <p class="source"> - doSomethingBasic() { - Profiler profiler = new Profiler("BASIC"); - - profiler.start("Subtask_1"); - doSubtaskOne(); - - profiler.start("Subtask_1"); - for (int i = 0; i < 5; i++) { - doSubtaskTwo(i); - } - profiler.start("Other"); - doOther(); - profiler.stop().print();</p> + <h2>Basic example</h2> + + <em>Example 8.1: Using the profiler (<a + href="../xref/chapter8/ProfilerUsageExample.html"> + logback-examples/src/main/java/chapter8/ProfilerUsageExample.java</a>)</em> + + <p class="source">package chapter8; + +import ch.qos.logback.classic.stopwatch.Profiler; + +public class ProfilerUsageExample { + + public static void main(String[] args) { + <b>Profiler profiler = new Profiler("BASIC");</b> + <b>profiler.start("A");</b> + doA(); + + <b>profiler.start("B");</b> + for (int i = 0; i < 5; i++) { + doSubtaskTwo(i); + } + <b>profiler.start("doOther");</b> + doOther(); + <b>profiler.stop().print();</b> + } + ... cut </p> + + <p>Running the above example will output the following output.</p> <p class="source">+ Profiler [BASIC] -|-- elapsed time [Subtask_1] 9.987 milliseconds. -|-- elapsed time [Subtask_1] 47.263 milliseconds. -|-- elapsed time [Other] 2.790 milliseconds. -|-- Total elapsed time [BASIC] 60.092 milliseconds. -</p> -</div> \ No newline at end of file +|-- elapsed time [A] 0.288 milliseconds. +|-- elapsed time [B] 24.717 milliseconds. +|-- elapsed time [Other] 22.085 milliseconds. +|-- Total elapsed time [BASIC] 50.691 milliseconds.</p> + + + <p>Instantiating a profiler starts a global stopwatch. Each call to + the start() method starts a new and named stopwatch. In addition to + sarting a named stopwatch, the start() method also causes the + previous stopwatch to stop. Thus, the call to + <code>profiler.start("A")</code> starts a stopwatch named "A". The + subsequent call to <code>profiler.start("B")</code> starts + stopwatch "B" and simultanously stops the stopwatch named + "A". Invoking the <code>stop()</code> on a profiler method stops + the last stopwatch as well as the global stopwatch which was + started when the profiler was instantiated. + </p> + + + <h2>Profiler nesting</h2> + + <p>Profilers can also be nested. By nesting profilers, it is + possible to measure a subtask which itself has subtasks that need + to be timed. </p> + +</div> +