profy

Stress test your app and measure performance

npm install profy
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Profy

Check the performance of your libraries by measuring memory consumption and time execution.

Profy is particularly useful when you stress test your application by looping. You add a Profy logger on each loop and in the end you get a meaningfull set of stats that you can assert on using your favorite testing suite.

Getting Started

Install...

npm install profy --save-dev

Profy has no main file, depending on what you want to measure you require the corresponding module.

Time Performance

The time performance API is pretty simple, use the start function to start measuring, log to mark a point and result when finished to get the results.

Requiring

var ProfyTime = require('profy/time');

Methods

Requiring will return you a constructor. You need to initialize a new performance timer using the new keyword:

var ProfyTime = require('profy/time');

var perf = new ProfyTime();

Method start()

Will mark the beggining of the performance test.

Method log(optMessage)

Will mark a point in time, optionally with a defined message. You can view the marks you made along with their messages when the perf tests finishes.

log() will return a number, indicating the index of the log message, which you can later use as an argument to the get(index) method.

Method stop() or results()

stop() and results() are aliases. They mark the end of the perfomance test and calculate all the required statistics. They both return the Performance Results Object:

The Performance Results Object


var results = perf.results();

results === {
  stats: {
    max: 2.779, // {number} Float, milliseconds, largest difference
    min: 0.008, // {number} Float, milliseconds, smallest difference
    mean: 0.258, // {number} Float, milliseconds, mean difference
    total: 5.668 // {number} Float, milliseconds, total execution time
  },

  // {number}, JS timestamp when ".start()" was invoked.
  firstLog: 1367251825022454,

  // {number}, JS timestamp when ".stop()" or ".results()"
  // was first invoked.
  lastLog: 1367251825028122,

  // "logs" is an array of JS timestamps, every time .log() 
  // is invoked a timestamp is being pushed to this array.
  logs: [1367251825022457, 1367251825022561 /* ... */ ],

  // "diffs" is an array of time differences in microseconds 
  // (1ms === 1000microsecond). 
  // This array is one-for-one with the "logs" array.
  diffs: [204, 104, 1269 /* ... */],

  // "tags" is array of strings, the messages that were provided when
  // invoking the ".log(message)" method. This array is one-for-one
  // with the "logs" array.
  tags: ['log 1', 'log 2' /* ... */]

};

Method get(index)

After stop() or results() have been invoked, a specific index from the logs can be requested using the get(index) method. Use as index the value returned by the log() method.


perf.start();

// get the index of the log mark (first one will be 0).
var index = perf.log('log one');

/* ... */

perf.log('log ten');

perf.stop();

var itemResult = perf.get(index);

itemResult === {
  time: 1367251825024312, // {number}, JS Timestamp of log
  diff: 104, // {number}, difference from previous log in microseconds
  tag: 'log one' // {string | null}, the log message used in log()
}

Method resultTable()

Returns a string with the results somewhat formated, use for console output when debugging.

Examples

var ProfyTime = require('profy/time');

var perf = new ProfyTime();

perf.start();

for (var i = 0; i < 10000; i++) {
  app.doSomething();
  perf.log(i);
}

console.log( perf.result() );

Memory Consumption

Memory consumption is measured by reading the value of the process.memoryUsage().heapUsed property. An initial measurement is taken and from there on every log() performed will log the value of that property.

Requiring

var ProfyMem = require('profy/mem');

Methods

Requiring will return you a constructor. You need to initialize a new Memory Consumption instance using the new keyword:

var ProfyMem = require('profy/mem');

var mem = new ProfyMem();

Method start()

Will mark the beggining of the measurement.

Method log(optMessage)

Will take a measurement., optionally with a defined message. You can view the marks you made along with their messages when the memory perf tests finishes.

log() will return a number, indicating the index of the log message, which you can later use as an argument to the get(index) method.

Method stop() or results()

stop() and results() are aliases. They mark the end of the perfomance test and calculate all the required statistics. They both return the Memory Results Object:

The Memory Results Object


var results = mem.results();

results === {
  stats: {
    max: 5134336, // {number} bytes, max bytes difference measured.
    min: 489832, // {number} bytes, min bytes difference measured.
    mean: 2597880 // {number} bytes, mean bytes difference.
  },
  percent: {
    max: 145.46, // {number} float, max in % compared to start
    min: 13.88,  // {number} float, min in % compared to start
    mean: 73.6,  // {number} float, mean in % compared to start
    last: 145.46 // {number} float, last in % compared to start
  }

  // {number} bytes used when start() was invoked.
  firstHeap: 3529800,

  // {number} bytes used when stop() was invoked.
  lastHeap: 5134336,

  // "heaps" is an array of bytes used when .log() is invoked.
  heaps: [4019632, 4735312 /* ... */ ],

  // "percentItems" is an array of floats, representing the %
  // difference with the first heap measurement.
  // This array is one-for-one with the "heaps" array.
  percentItems: [13.88, 34.15 /* ... */ ],

  // "tags" is array of strings, the messages that were provided when
  // invoking the ".log(message)" method. This array is one-for-one
  // with the "heaps" array.
  tags: ['log 1', 'log 2' /* ... */]

};

Method get(index)

After stop() or results() have been invoked, a specific index from the logs can be requested using the get(index) method. Use as index the value returned by the log() method.


mem.start();

// get the index of the log mark (first one will be 0).
var index = mem.log('log one');

/* ... */

mem.log('log ten');

mem.stop();

var itemResult = mem.get(index);

itemResult === {
  heap: 6077936, // {number}, bytes used
  percent: 108.5, // {number}, float, % difference from first heap
  tag: 'log one' // {string | null}, the log message used in log()
}

Method resultTable()

Returns a string with the results somewhat formated, use for console output when debugging.

Examples

var ProfyMem = require('profy/mem');

var mem = new ProfyMem();

mem.start();

for (var i = 0; i < 10000; i++) {
  app.doSomething();
  mem.log(i);
}

console.log( mem.result() );

Release History

  • v0.0.5, 29 Apr 2013
    • API cleanup, documentation
    • Bug fixes
  • v0.0.1, Mid Apr 2013
    • Big Bang

License

Copyright (c) 2013 Thanasis Polychronakis Licensed under the MIT.

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