/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview Performance timer.
*
* {@see goog.testing.benchmark} for an easy way to use this functionality.
*/
goog.setTestOnly('goog.testing.PerformanceTimer');
goog.provide('goog.testing.PerformanceTimer');
goog.provide('goog.testing.PerformanceTimer.Task');
goog.require('goog.Thenable');
goog.require('goog.array');
goog.require('goog.async.Deferred');
goog.require('goog.math');
/**
* Creates a performance timer that runs test functions a number of times to
* generate timing samples, and provides performance statistics (minimum,
* maximum, average, and standard deviation).
* @param {number=} opt_numSamples Number of times to run the test function;
* defaults to 10.
* @param {number=} opt_timeoutInterval Number of milliseconds after which the
* test is to be aborted; defaults to 5 seconds (5,000ms).
* @constructor
*/
goog.testing.PerformanceTimer = function(opt_numSamples, opt_timeoutInterval) {
'use strict';
/**
* Number of times the test function is to be run; defaults to 10.
* @private {number}
*/
this.numSamples_ = opt_numSamples || 10;
/**
* Number of milliseconds after which the test is to be aborted; defaults to
* 5,000ms.
* @private {number}
*/
this.timeoutInterval_ = opt_timeoutInterval || 5000;
/**
* Whether to discard outliers (i.e. the smallest and the largest values)
* from the sample set before computing statistics. Defaults to false.
* @private {boolean}
*/
this.discardOutliers_ = false;
};
/**
* A function whose subsequent calls differ in milliseconds. Used to calculate
* the start and stop checkpoint times for runs. Note that high performance
* timers do not necessarily return the current time in milliseconds.
* @return {number}
* @private
*/
goog.testing.PerformanceTimer.now_ = function() {
'use strict';
// goog.now is used in DEBUG mode to make the class easier to test.
return !goog.DEBUG && window.performance && window.performance.now ?
window.performance.now() :
goog.now();
};
/**
* @return {number} The number of times the test function will be run.
*/
goog.testing.PerformanceTimer.prototype.getNumSamples = function() {
'use strict';
return this.numSamples_;
};
/**
* Sets the number of times the test function will be run.
* @param {number} numSamples Number of times to run the test function.
*/
goog.testing.PerformanceTimer.prototype.setNumSamples = function(numSamples) {
'use strict';
this.numSamples_ = numSamples;
};
/**
* @return {number} The number of milliseconds after which the test times out.
*/
goog.testing.PerformanceTimer.prototype.getTimeoutInterval = function() {
'use strict';
return this.timeoutInterval_;
};
/**
* Sets the number of milliseconds after which the test times out.
* @param {number} timeoutInterval Timeout interval in ms.
*/
goog.testing.PerformanceTimer.prototype.setTimeoutInterval = function(
timeoutInterval) {
'use strict';
this.timeoutInterval_ = timeoutInterval;
};
/**
* Sets whether to ignore the smallest and the largest values when computing
* stats.
* @param {boolean} discard Whether to discard outlier values.
*/
goog.testing.PerformanceTimer.prototype.setDiscardOutliers = function(discard) {
'use strict';
this.discardOutliers_ = discard;
};
/**
* @return {boolean} Whether outlier values are discarded prior to computing
* stats.
*/
goog.testing.PerformanceTimer.prototype.isDiscardOutliers = function() {
'use strict';
return this.discardOutliers_;
};
/**
* Executes the test function the required number of times (or until the
* test run exceeds the timeout interval, whichever comes first). Returns
* an object containing the following:
* <pre>
* {
* 'average': average execution time (ms)
* 'count': number of executions (may be fewer than expected due to timeout)
* 'maximum': longest execution time (ms)
* 'minimum': shortest execution time (ms)
* 'standardDeviation': sample standard deviation (ms)
* 'total': total execution time (ms)
* }
* </pre>
*
* @param {Function} testFn Test function whose performance is to
* be measured.
* @return {!Object} Object containing performance stats.
*/
goog.testing.PerformanceTimer.prototype.run = function(testFn) {
'use strict';
return this.runTask(new goog.testing.PerformanceTimer.Task(
/** @type {goog.testing.PerformanceTimer.TestFunction} */ (testFn)));
};
/**
* Executes the test function of the specified task as described in
* `run`. In addition, if specified, the set up and tear down functions of
* the task are invoked before and after each invocation of the test function.
* @see goog.testing.PerformanceTimer#run
* @param {goog.testing.PerformanceTimer.Task} task A task describing the test
* function to invoke.
* @return {!Object} Object containing performance stats.
*/
goog.testing.PerformanceTimer.prototype.runTask = function(task) {
'use strict';
var samples = [];
var testStart = goog.testing.PerformanceTimer.now_();
var totalRunTime = 0;
var testFn = task.getTest();
var setUpFn = task.getSetUp();
var tearDownFn = task.getTearDown();
for (var i = 0; i < this.numSamples_ && totalRunTime <= this.timeoutInterval_;
i++) {
setUpFn();
var sampleStart = goog.testing.PerformanceTimer.now_();
testFn();
var sampleEnd = goog.testing.PerformanceTimer.now_();
tearDownFn();
samples[i] = sampleEnd - sampleStart;
totalRunTime = sampleEnd - testStart;
}
return this.finishTask_(samples);
};
/**
* Finishes the run of a task by creating a result object from samples, in the
* format described in `run`.
* @see goog.testing.PerformanceTimer#run
* @param {!Array<number>} samples The samples to analyze.
* @return {!Object} Object containing performance stats.
* @private
*/
goog.testing.PerformanceTimer.prototype.finishTask_ = function(samples) {
'use strict';
if (this.discardOutliers_ && samples.length > 2) {
goog.array.remove(samples, Math.min.apply(null, samples));
goog.array.remove(samples, Math.max.apply(null, samples));
}
return goog.testing.PerformanceTimer.createResults(samples);
};
/**
* Executes the test function of the specified task asynchronously. The test
* function may return a Thenable to allow for asynchronous execution. In
* addition, if specified, the setUp and tearDown functions of the task are
* invoked before and after each invocation of the test function. Note,
* setUp/tearDown too may return Thenables for asynchronous execution.
* @see goog.testing.PerformanceTimer#run
* @param {goog.testing.PerformanceTimer.Task} task A task describing the test
* function to invoke.
* @return {!goog.async.Deferred} The deferred result, eventually an object
* containing performance stats.
*/
goog.testing.PerformanceTimer.prototype.runAsyncTask = function(task) {
'use strict';
var samples = [];
var testStart = goog.testing.PerformanceTimer.now_();
var testFn = task.getTest();
var setUpFn = task.getSetUp();
var tearDownFn = task.getTearDown();
// Note that this uses a separate code path from runTask() because
// implementing runTask() in terms of runAsyncTask() could easily cause
// a stack overflow if there are many iterations.
return goog.async.Deferred.fromPromise(this.runAsyncTaskSample_(
testFn, setUpFn, tearDownFn, samples, testStart));
};
/**
* Runs a task once, waits for the test function to complete asynchronously
* and starts another run if not enough samples have been collected. Otherwise
* finishes this task.
* @param {goog.testing.PerformanceTimer.TestFunction} testFn The test function.
* @param {goog.testing.PerformanceTimer.TestFunction} setUpFn The set up
* function that will be called once before the test function is run.
* @param {goog.testing.PerformanceTimer.TestFunction} tearDownFn The set up
* function that will be called once after the test function completed.
* @param {!Array<number>} samples The time samples from all runs of the test
* function so far.
* @param {number} testStart The timestamp when the first sample was started.
* @return {!Promise} A promise that returns the completed performance stats.
* @private
*/
goog.testing.PerformanceTimer.prototype.runAsyncTaskSample_ = function(
testFn, setUpFn, tearDownFn, samples, testStart) {
'use strict';
const timer = this;
let promise = Promise.resolve();
let sampleStart;
let sampleEnd;
for (let i = 0; i < timer.numSamples_; i++) {
promise = promise.then(setUpFn)
.then(() => {
'use strict';
sampleStart = goog.testing.PerformanceTimer.now_();
})
.then(testFn)
.then(() => {
'use strict';
sampleEnd = goog.testing.PerformanceTimer.now_();
})
.then(tearDownFn)
.then(() => {
'use strict';
samples.push(sampleEnd - sampleStart);
const totalRunTime = sampleEnd - testStart;
if (totalRunTime > timer.timeoutInterval_) {
// If timeout is exceeded, bypass remaining samples via
// errback.
throw Error('PerformanceTimer.Timeout');
}
});
}
return promise
.catch((err) => {
// Convert timeout error to success.
if (err instanceof Error &&
err.message === 'PerformanceTimer.Timeout') {
return true;
}
throw err;
})
.then(() => timer.finishTask_(samples));
};
/**
* Return the median of the samples.
* @param {!Array<number>} samples
* @return {number}
*/
goog.testing.PerformanceTimer.median = function(samples) {
'use strict';
samples.sort(function(a, b) {
'use strict';
return a - b;
});
let half = Math.floor(samples.length / 2);
if (samples.length % 2) {
return samples[half];
} else {
return (samples[half - 1] + samples[half]) / 2.0;
}
};
/**
* Creates a performance timer results object by analyzing a given array of
* sample timings.
* @param {!Array<number>} samples The samples to analyze.
* @return {!Object} Object containing performance stats.
*/
goog.testing.PerformanceTimer.createResults = function(samples) {
'use strict';
return {
'average': goog.math.average.apply(null, samples),
'count': samples.length,
'median': goog.testing.PerformanceTimer.median(samples),
'maximum': Math.max.apply(null, samples),
'minimum': Math.min.apply(null, samples),
'standardDeviation': goog.math.standardDeviation.apply(null, samples),
'total': goog.math.sum.apply(null, samples)
};
};
/**
* A test function whose performance should be measured or a setUp/tearDown
* function. It may optionally return a Thenable (e.g. a promise) to
* for asynchronous execution using the runAsyncTask method.
* @see goog.testing.PerformanceTimer#runAsyncTask
* @typedef {function():(!goog.Thenable|undefined)}
*/
goog.testing.PerformanceTimer.TestFunction;
/**
* A task for the performance timer to measure. Callers can specify optional
* setUp and tearDown methods to control state before and after each run of the
* test function.
* @param {goog.testing.PerformanceTimer.TestFunction} test Test function whose
* performance is to be measured.
* @constructor
* @final
*/
goog.testing.PerformanceTimer.Task = function(test) {
'use strict';
/**
* The test function to time.
* @type {goog.testing.PerformanceTimer.TestFunction}
* @private
*/
this.test_ = test;
};
/**
* An optional set up function to run before each invocation of the test
* function.
* @type {goog.testing.PerformanceTimer.TestFunction}
* @private
*/
goog.testing.PerformanceTimer.Task.prototype.setUp_ = goog.nullFunction;
/**
* An optional tear down function to run after each invocation of the test
* function.
* @type {goog.testing.PerformanceTimer.TestFunction}
* @private
*/
goog.testing.PerformanceTimer.Task.prototype.tearDown_ = goog.nullFunction;
/**
* @return {goog.testing.PerformanceTimer.TestFunction} The test function to
* time.
*/
goog.testing.PerformanceTimer.Task.prototype.getTest = function() {
'use strict';
return this.test_;
};
/**
* Specifies a set up function to be invoked before each invocation of the test
* function.
* @param {goog.testing.PerformanceTimer.TestFunction} setUp The set up
* function.
* @return {!goog.testing.PerformanceTimer.Task} This task.
*/
goog.testing.PerformanceTimer.Task.prototype.withSetUp = function(setUp) {
'use strict';
this.setUp_ = setUp;
return this;
};
/**
* @return {goog.testing.PerformanceTimer.TestFunction} The set up function or
* the default no-op function if none was specified.
*/
goog.testing.PerformanceTimer.Task.prototype.getSetUp = function() {
'use strict';
return this.setUp_;
};
/**
* Specifies a tear down function to be invoked after each invocation of the
* test function.
* @param {goog.testing.PerformanceTimer.TestFunction} tearDown The tear down
* function.
* @return {!goog.testing.PerformanceTimer.Task} This task.
*/
goog.testing.PerformanceTimer.Task.prototype.withTearDown = function(tearDown) {
'use strict';
this.tearDown_ = tearDown;
return this;
};
/**
* @return {goog.testing.PerformanceTimer.TestFunction} The tear down function
* or the default no-op function if none was specified.
*/
goog.testing.PerformanceTimer.Task.prototype.getTearDown = function() {
'use strict';
return this.tearDown_;
};
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