tor-browser

base.js (12998B)

---

// Copyright 2013 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
//     * Redistributions of source code must retain the above copyright
//       notice, this list of conditions and the following disclaimer.
//     * Redistributions in binary form must reproduce the above
//       copyright notice, this list of conditions and the following
//       disclaimer in the documentation and/or other materials provided
//       with the distribution.
//     * Neither the name of Google Inc. nor the names of its
//       contributors may be used to endorse or promote products derived
//       from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.


// Performance.now is used in latency benchmarks, the fallback is Date.now.
var performance = performance || {};
performance.now = (function() {
 return performance.now       ||
        performance.mozNow    ||
        performance.msNow     ||
        performance.oNow      ||
        performance.webkitNow ||
        Date.now;
})();

// Simple framework for running the benchmark suites and
// computing a score based on the timing measurements.


// A benchmark has a name (string) and a function that will be run to
// do the performance measurement. The optional setup and tearDown
// arguments are functions that will be invoked before and after
// running the benchmark, but the running time of these functions will
// not be accounted for in the benchmark score.
function Benchmark(name, doWarmup, doDeterministic, deterministicIterations, 
                  run, setup, tearDown, rmsResult, minIterations) {
 this.name = name;
 this.doWarmup = doWarmup;
 this.doDeterministic = doDeterministic;
 this.deterministicIterations = deterministicIterations;
 this.run = run;
 this.Setup = setup ? setup : function() { };
 this.TearDown = tearDown ? tearDown : function() { };
 this.rmsResult = rmsResult ? rmsResult : null; 
 this.minIterations = minIterations ? minIterations : 32;
}


// Benchmark results hold the benchmark and the measured time used to
// run the benchmark. The benchmark score is computed later once a
// full benchmark suite has run to completion. If latency is set to 0
// then there is no latency score for this benchmark.
function BenchmarkResult(benchmark, time, latency) {
 this.benchmark = benchmark;
 this.time = time;
 this.latency = latency;
}


// Automatically convert results to numbers. Used by the geometric
// mean computation.
BenchmarkResult.prototype.valueOf = function() {
 return this.time;
}


// Suites of benchmarks consist of a name and the set of benchmarks in
// addition to the reference timing that the final score will be based
// on. This way, all scores are relative to a reference run and higher
// scores implies better performance.
function BenchmarkSuite(name, reference, benchmarks) {
 this.name = name;
 this.reference = reference;
 this.benchmarks = benchmarks;
 BenchmarkSuite.suites.push(this);
}


// Keep track of all declared benchmark suites.
BenchmarkSuite.suites = [];

// Scores are not comparable across versions. Bump the version if
// you're making changes that will affect that scores, e.g. if you add
// a new benchmark or change an existing one.
BenchmarkSuite.version = '9';


// Defines global benchsuite running mode that overrides benchmark suite 
// behavior. Intended to be set by the benchmark driver. Undefined 
// values here allow a benchmark to define behaviour itself.
BenchmarkSuite.config = {
 doWarmup: undefined,
 doDeterministic: undefined
};


// Override the alert function to throw an exception instead.
alert = function(s) {
 throw "Alert called with argument: " + s;
};


// To make the benchmark results predictable, we replace Math.random
// with a 100% deterministic alternative.
BenchmarkSuite.ResetRNG = function() {
 Math.random = (function() {
   var seed = 49734321;
   return function() {
     // Robert Jenkins' 32 bit integer hash function.
     seed = ((seed + 0x7ed55d16) + (seed << 12))  & 0xffffffff;
     seed = ((seed ^ 0xc761c23c) ^ (seed >>> 19)) & 0xffffffff;
     seed = ((seed + 0x165667b1) + (seed << 5))   & 0xffffffff;
     seed = ((seed + 0xd3a2646c) ^ (seed << 9))   & 0xffffffff;
     seed = ((seed + 0xfd7046c5) + (seed << 3))   & 0xffffffff;
     seed = ((seed ^ 0xb55a4f09) ^ (seed >>> 16)) & 0xffffffff;
     return (seed & 0xfffffff) / 0x10000000;
   };
 })();
}


// Runs all registered benchmark suites and optionally yields between
// each individual benchmark to avoid running for too long in the
// context of browsers. Once done, the final score is reported to the
// runner.
BenchmarkSuite.RunSuites = function(runner, skipBenchmarks) {
 skipBenchmarks = typeof skipBenchmarks === 'undefined' ? [] : skipBenchmarks;
 var continuation = null;
 var suites = BenchmarkSuite.suites;
 var length = suites.length;
 BenchmarkSuite.scores = [];
 var index = 0;
 function RunStep() {
   while (continuation || index < length) {
     if (continuation) {
       continuation = continuation();
     } else {
       var suite = suites[index++];
       if (runner.NotifyStart) runner.NotifyStart(suite.name);
       if (skipBenchmarks.indexOf(suite.name) > -1) {
         suite.NotifySkipped(runner);
       } else {
         continuation = suite.RunStep(runner);
       }
     }
     if (continuation && typeof window != 'undefined' && window.setTimeout) {
       window.setTimeout(RunStep, 25);
       return;
     }
   }

   // show final result
   if (runner.NotifyScore) {
     var score = BenchmarkSuite.GeometricMean(BenchmarkSuite.scores);
     var formatted = BenchmarkSuite.FormatScore(100 * score);
     runner.NotifyScore(formatted);
   }
 }
 RunStep();
}


// Counts the total number of registered benchmarks. Useful for
// showing progress as a percentage.
BenchmarkSuite.CountBenchmarks = function() {
 var result = 0;
 var suites = BenchmarkSuite.suites;
 for (var i = 0; i < suites.length; i++) {
   result += suites[i].benchmarks.length;
 }
 return result;
}


// Computes the geometric mean of a set of numbers.
BenchmarkSuite.GeometricMean = function(numbers) {
 var log = 0;
 for (var i = 0; i < numbers.length; i++) {
   log += Math.log(numbers[i]);
 }
 return Math.pow(Math.E, log / numbers.length);
}


// Computes the geometric mean of a set of throughput time measurements.
BenchmarkSuite.GeometricMeanTime = function(measurements) {
 var log = 0;
 for (var i = 0; i < measurements.length; i++) {
   log += Math.log(measurements[i].time);
 }
 return Math.pow(Math.E, log / measurements.length);
}


// Computes the geometric mean of a set of rms measurements.
BenchmarkSuite.GeometricMeanLatency = function(measurements) {
 var log = 0;
 var hasLatencyResult = false;
 for (var i = 0; i < measurements.length; i++) {
   if (measurements[i].latency != 0) {
     log += Math.log(measurements[i].latency);
     hasLatencyResult = true;
   }
 }
 if (hasLatencyResult) {
   return Math.pow(Math.E, log / measurements.length);
 } else {
   return 0;
 }
}


// Converts a score value to a string with at least three significant
// digits.
BenchmarkSuite.FormatScore = function(value) {
 if (value > 100) {
   return value.toFixed(0);
 } else {
   return value.toPrecision(3);
 }
}

// Notifies the runner that we're done running a single benchmark in
// the benchmark suite. This can be useful to report progress.
BenchmarkSuite.prototype.NotifyStep = function(result) {
 this.results.push(result);
 if (this.runner.NotifyStep) this.runner.NotifyStep(result.benchmark.name);
}


// Notifies the runner that we're done with running a suite and that
// we have a result which can be reported to the user if needed.
BenchmarkSuite.prototype.NotifyResult = function() {
 var mean = BenchmarkSuite.GeometricMeanTime(this.results);
 var score = this.reference[0] / mean;
 BenchmarkSuite.scores.push(score);
 if (this.runner.NotifyResult) {
   var formatted = BenchmarkSuite.FormatScore(100 * score);
   this.runner.NotifyResult(this.name, formatted);
 }
 if (this.reference.length == 2) {
   var meanLatency = BenchmarkSuite.GeometricMeanLatency(this.results);
   if (meanLatency != 0) {
     var scoreLatency = this.reference[1] / meanLatency;
     BenchmarkSuite.scores.push(scoreLatency);
     if (this.runner.NotifyResult) {
       var formattedLatency = BenchmarkSuite.FormatScore(100 * scoreLatency)
       this.runner.NotifyResult(this.name + "Latency", formattedLatency);
     }
   }
 }
}


BenchmarkSuite.prototype.NotifySkipped = function(runner) {
 BenchmarkSuite.scores.push(1);  // push default reference score.
 if (runner.NotifyResult) {
   runner.NotifyResult(this.name, "Skipped");
 }
}


// Notifies the runner that running a benchmark resulted in an error.
BenchmarkSuite.prototype.NotifyError = function(error) {
 if (this.runner.NotifyError) {
   this.runner.NotifyError(this.name, error);
 }
 if (this.runner.NotifyStep) {
   this.runner.NotifyStep(this.name);
 }
}


// Runs a single benchmark for at least a second and computes the
// average time it takes to run a single iteration.
BenchmarkSuite.prototype.RunSingleBenchmark = function(benchmark, data) {
 var config = BenchmarkSuite.config;
 var doWarmup = config.doWarmup !== undefined 
                ? config.doWarmup 
                : benchmark.doWarmup;
 var doDeterministic = config.doDeterministic !== undefined 
                       ? config.doDeterministic 
                       : benchmark.doDeterministic;

 function Measure(data) {
   var elapsed = 0;
   var start = new Date();
 
 // Run either for 1 second or for the number of iterations specified
 // by minIterations, depending on the config flag doDeterministic.
   for (var i = 0; (doDeterministic ? 
     i<benchmark.deterministicIterations : elapsed < 1000); i++) {
     benchmark.run();
     elapsed = new Date() - start;
   }
   if (data != null) {
     data.runs += i;
     data.elapsed += elapsed;
   }
 }

 // Sets up data in order to skip or not the warmup phase.
 if (!doWarmup && data == null) {
   data = { runs: 0, elapsed: 0 };
 }

 if (data == null) {
   Measure(null);
   return { runs: 0, elapsed: 0 };
 } else {
   Measure(data);
   // If we've run too few iterations, we continue for another second.
   if (data.runs < benchmark.minIterations) return data;
   var usec = (data.elapsed * 1000) / data.runs;
   var rms = (benchmark.rmsResult != null) ? benchmark.rmsResult() : 0;
   this.NotifyStep(new BenchmarkResult(benchmark, usec, rms));
   return null;
 }
}


// This function starts running a suite, but stops between each
// individual benchmark in the suite and returns a continuation
// function which can be invoked to run the next benchmark. Once the
// last benchmark has been executed, null is returned.
BenchmarkSuite.prototype.RunStep = function(runner) {
 BenchmarkSuite.ResetRNG();
 this.results = [];
 this.runner = runner;
 var length = this.benchmarks.length;
 var index = 0;
 var suite = this;
 var data;

 // Run the setup, the actual benchmark, and the tear down in three
 // separate steps to allow the framework to yield between any of the
 // steps.

 function RunNextSetup() {
   if (index < length) {
     try {
       suite.benchmarks[index].Setup();
     } catch (e) {
       suite.NotifyError(e);
       return null;
     }
     return RunNextBenchmark;
   }
   suite.NotifyResult();
   return null;
 }

 function RunNextBenchmark() {
   try {
     data = suite.RunSingleBenchmark(suite.benchmarks[index], data);
   } catch (e) {
     suite.NotifyError(e);
     return null;
   }
   // If data is null, we're done with this benchmark.
   return (data == null) ? RunNextTearDown : RunNextBenchmark();
 }

 function RunNextTearDown() {
   try {
     suite.benchmarks[index++].TearDown();
   } catch (e) {
     suite.NotifyError(e);
     return null;
   }
   return RunNextSetup;
 }

 // Start out running the setup.
 return RunNextSetup();
}