This is a set of basic performance tests for promise implementations. As is almost always the case, take these with the usual grains of salt. That said, they should give a reasonable ballpark comparison of the performance characteristics of common, basic operations that most promise libraries provide.
Of course, performance is not the only thing to consider in a promise library. Interoperability via a proposed standard, such as Promises/A, API convenience, safety, and even code size (for browser applications) are all important, application-specific considerations.
Right now, the tests are runnable en masse via npm test in unix-like environments, and individually via node in other envs.
- Clone the repo
npm installto install the promise implementations to be tested- Run tests:
- Run all tests:
bin/pperf - Run a single test:
bin/pperf -t <test> - Run a single implementation
bin/pperf -a <implementation> - Print available tests and implementations
bin/pperf -h
- Run all tests:
when.js uses synchronous resolutions, and no longer uses Object.freeze() as of v1.6.0, to avoid this unfortunate v8-imposed performance penalty.
avow is an example Promises/A+ implementation. In its default configuration, it uses asynchronous resolutions and does not call Object.freeze. However, it can be configured to use synchronous resolutions, and/or Object.freeze. Performance tests are run using the default configuration.
Q uses asynchronous resolutions, and calls Object.freeze on its promises, and so it incurs the v8-imposed performance penalty.
RSVP uses asynchronous resolutions, and doesn't use Object.freeze.
deferred uses synchronous resolutions, and doesn't use Object.freeze.
jQuery uses synchronous resolutions, and it doesn't use Object.freeze.
These tests use jQuery via jquery-browserify, with jsdom for support. This approach was taken from the Promises Test Suite, and currently, appears to be the only way to use jQuery 1.8.x in node.
jQuery Deferred is not intended to be fully Promises/A compliant in its forwarding behavior. We've done our best to design the tests so that that does not affect the performance characteristics. While this does affect the computation results of some tests, it can be ignored for most performance testing purposes.
Laisseze-faire uses synchronous resolutions, and it doesn't provide proxies by default.
Uses synchronous resolutions an doesn't freeze its objects.
These tests were run on a MacBook Pro Intel Core i7, 2.3Ghz, 8g RAM, 256g SSD, using Node.js v0.8.14 installed via nvm and the following library versions (npm ls):
├── avow@1.0.0
├── b@2.0.0
├─┬ cli-table@0.2.0
│ └── colors@0.3.0
├── colors@0.6.0-1
├─┬ commander@1.1.1
│ └── keypress@0.1.0
├─┬ deferred@0.6.1
│ ├── es5-ext@0.9.1
│ ├── event-emitter@0.2.1
│ └── next-tick@0.1.0
├── exec@0.0.4
├── jquery-browserify@1.8.1
├─┬ jsdom@0.3.4
│ ├─┬ contextify@0.1.3
│ │ └── bindings@1.0.0
│ ├── cssom@0.2.5
│ ├── cssstyle@0.2.3
│ ├── htmlparser@1.7.6
│ ├── nwmatcher@1.3.0
│ └─┬ request@2.12.0
│ ├─┬ form-data@0.0.6
│ │ ├── async@0.1.22
│ │ └─┬ combined-stream@0.0.3
│ │ └── delayed-stream@0.0.5
│ └── mime@1.2.9
├── laissez-faire@0.10.1
├── micro-promise@0.1.0
├── promises-a@2.3.0
├─┬ promisify@0.1.0
│ ├── laissez-faire@0.10.1
│ └── sliced@0.0.3
├── q@0.8.12
├── randy@1.4.0
├── rsvp@1.2.0
├── stripcolorcodes@0.1.0
└── when@1.7.1
Each test is sorted from best to worst time. Times are in milliseconds, and Diff is the percentage difference from the best time.
fulfill x50
┌───────────────┬────────────┬──────────────┬──────────┐
│ │ total (ms) │ average (ns) │ diff (%) │
├───────────────┼────────────┼──────────────┼──────────┤
│ laissez-faire │ 1 │ 22,154 │ - │
│ micro-promise │ 1 │ 23,523 │ 6 │
│ then.promise │ 1 │ 29,292 │ 32 │
│ deferred │ 2 │ 34,915 │ 58 │
│ rsvp │ 2 │ 45,015 │ 103 │
│ when │ 3 │ 52,621 │ 138 │
│ q │ 6 │ 112,225 │ 407 │
│ avow │ 21 │ 419,085 │ 1,792 │
└───────────────┴────────────┴──────────────┴──────────┘
fulfilled x50
┌───────────────┬────────────┬──────────────┬──────────┐
│ │ total (ms) │ average (ns) │ diff (%) │
├───────────────┼────────────┼──────────────┼──────────┤
│ laissez-faire │ 0 │ 3,238 │ - │
│ q │ 0 │ 8,942 │ 176 │
│ deferred │ 1 │ 10,012 │ 209 │
│ then.promise │ 1 │ 11,181 │ 245 │
│ when │ 1 │ 15,343 │ 374 │
│ rsvp │ 1 │ 18,343 │ 467 │
│ avow │ 1 │ 28,720 │ 787 │
│ micro-promise │ 2 │ 32,549 │ 905 │
└───────────────┴────────────┴──────────────┴──────────┘
pending-sequence x50
┌───────────────┬────────────┬──────────────┬──────────┐
│ │ total (ms) │ average (ns) │ diff (%) │
├───────────────┼────────────┼──────────────┼──────────┤
│ laissez-faire │ 4 │ 71,567 │ - │
│ when │ 5 │ 96,487 │ 35 │
│ then.promise │ 11 │ 211,406 │ 195 │
│ rsvp │ 18 │ 368,980 │ 416 │
│ deferred │ 19 │ 382,560 │ 435 │
│ avow │ 23 │ 463,866 │ 548 │
│ micro-promise │ 42 │ 839,174 │ 1,073 │
│ q │ 1,046 │ 20,929,492 │ 29,144 │
└───────────────┴────────────┴──────────────┴──────────┘
pending x50
┌───────────────┬────────────┬──────────────┬──────────┐
│ │ total (ms) │ average (ns) │ diff (%) │
├───────────────┼────────────┼──────────────┼──────────┤
│ laissez-faire │ 0 │ 2,009 │ - │
│ then.promise │ 0 │ 6,157 │ 207 │
│ when │ 0 │ 8,465 │ 321 │
│ avow │ 0 │ 8,536 │ 325 │
│ rsvp │ 1 │ 12,898 │ 542 │
│ deferred │ 1 │ 20,508 │ 921 │
│ micro-promise │ 1 │ 28,069 │ 1,297 │
│ q │ 22 │ 445,010 │ 22,053 │
└───────────────┴────────────┴──────────────┴──────────┘
reject x50
┌───────────────┬────────────┬──────────────┬──────────┐
│ │ total (ms) │ average (ns) │ diff (%) │
├───────────────┼────────────┼──────────────┼──────────┤
│ laissez-faire │ 1 │ 22,888 │ - │
│ micro-promise │ 1 │ 24,174 │ 6 │
│ deferred │ 2 │ 30,424 │ 33 │
│ then.promise │ 2 │ 31,622 │ 38 │
│ rsvp │ 2 │ 47,550 │ 108 │
│ when │ 3 │ 55,588 │ 143 │
│ q │ 7 │ 144,399 │ 531 │
│ avow │ 15 │ 301,711 │ 1,218 │
└───────────────┴────────────┴──────────────┴──────────┘
rejected x50
┌───────────────┬────────────┬──────────────┬──────────┐
│ │ total (ms) │ average (ns) │ diff (%) │
├───────────────┼────────────┼──────────────┼──────────┤
│ laissez-faire │ 0 │ 2,821 │ - │
│ deferred │ 0 │ 5,076 │ 80 │
│ q │ 0 │ 6,745 │ 139 │
│ then.promise │ 1 │ 10,869 │ 285 │
│ rsvp │ 1 │ 18,310 │ 549 │
│ when │ 1 │ 23,738 │ 741 │
│ avow │ 1 │ 25,491 │ 804 │
│ micro-promise │ 2 │ 31,453 │ 1,015 │
└───────────────┴────────────┴──────────────┴──────────┘
resolve-sequence x50
┌───────────────┬────────────┬──────────────┬──────────┐
│ │ total (ms) │ average (ns) │ diff (%) │
├───────────────┼────────────┼──────────────┼──────────┤
│ laissez-faire │ 6 │ 116,708 │ - │
│ micro-promise │ 9 │ 170,376 │ 46 │
│ then.promise │ 9 │ 172,152 │ 48 │
│ when │ 13 │ 255,559 │ 119 │
│ rsvp │ 31 │ 626,100 │ 436 │
│ deferred │ 34 │ 680,855 │ 483 │
│ avow │ 59 │ 1,185,774 │ 916 │
│ q │ 141 │ 2,824,616 │ 2,320 │
└───────────────┴────────────┴──────────────┴──────────┘
resolved-sequence x50
┌───────────────┬────────────┬──────────────┬──────────┐
│ │ total (ms) │ average (ns) │ diff (%) │
├───────────────┼────────────┼──────────────┼──────────┤
│ laissez-faire │ 6 │ 126,023 │ - │
│ deferred │ 10 │ 199,373 │ 58 │
│ when │ 12 │ 241,293 │ 91 │
│ then.promise │ 18 │ 350,516 │ 178 │
│ rsvp │ 49 │ 983,637 │ 681 │
│ avow │ 63 │ 1,254,229 │ 895 │
│ micro-promise │ 67 │ 1,336,711 │ 961 │
│ q │ 1,313 │ 26,260,639 │ 20,738 │
└───────────────┴────────────┴──────────────┴──────────┘