jsPerf.app is an online JavaScript performance benchmark test runner & jsperf.com mirror. It is a complete rewrite in homage to the once excellent jsperf.com now with hopefully a more modern & maintainable codebase.

jsperf.com URLs are mirrored at the same path, e.g:

https://jsperf.com/negative-modulo/2

Can be accessed at:

https://jsperf.app/negative-modulo/2

Unrolled loops (v11)

Revision 11 of this benchmark created on August 18, 2010

Description

It seems the latest and greatest JavaScript engines have catched up and loop unrolling is not as great a speedup as it once was. Still, both unrolled loop variants are 10% to 25% faster than the for loop on both Safari 5 and Chrome 5.

Preparation HTML

<script>
  var a = 0;
</script>

Test runner

Ready to run.

Testing in
Test		Ops/sec
For loop	`for (var i = 0; i < 100; i++) a++;`	ready
Unrolled loop	`a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++;`	ready
Unrolled loop (1 statement)	`a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++;`	ready
Partial Unrolling	`for (var i = 0; i < 10; i++) { a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; }`	ready
Larger Partial Unrolling	`for (var i = 0; i < 2; i++) { a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; a++; }`	ready
Larger Partial Unrolling (single statement)	`for (var i = 0; i < 2; i++) { a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++, a++; }`	ready

Revisions

You can edit these tests or add more tests to this page by appending /edit to the URL.

Revision 1: published by Thomas Fuchs on August 16, 2010
Revision 2: published by elliottcable on August 16, 2010
Revision 3: published by Kristof Neirynck on August 16, 2010
Revision 4: published by Micheil Smith on August 16, 2010
Revision 6: published by Ryan Tenney on August 16, 2010
Revision 7: published by gonchuki on August 16, 2010
Revision 8: published by TW on August 16, 2010
Revision 11: published on August 18, 2010
Revision 16: published on February 23, 2015