performance of various javascript calling methods and proxies

median times in miliseconds for 20000 reps of a simple counting algorithm, testing various forms of dispatch, eg closures, classes, goog.inherit, dojo.hitch (method.apply), dojo.delegate, dojo.extend, a few of my methods similar to hitch, inline, custom function as a proxy, and proxies using method.call instead of method.apply


caveat emptor: benchmarking is hard, and i'm new enough to javascript that i'm not 100% confident in the numbers. my tests are very simple, but i have tried to make them difficult to optimize out. the basic algorithm is the following, which is far from foolproof.



function(ko) {
    ko = ++ko % this.po;
    ko == 0 && (this.po++);

    return ko;

}

	median			std dev
	Chrome	Firefox 3.5	IE 7	Chrome	Firefox 3.5	IE 7
class	2	14	62	0.41	0.85	0.5
goog.inherit	2	16	78	0.73	0.9	0.35
closure	2	16	63	0.5	0.62	0.5
dojo.delegate	3	15	63	0.52	0.7	4.03
dojo.extend	3	14	63	0.62	0.64	0.45
dojo.hitch	13	141	297	1.25	190.2	7.93
nqo.proxy	4	136	281	0.41	139.61	0.5
hitchArgs	256	381	1312	3.33	189.79	7.18
proxyArgs	202	273	813	5.58	190.16	6.43
functionProxy	3	24	125	0.26	0.88	0
functionArgs	3	24	125	0.41	0.9	4.12
callProxy	6	35	156	0.45	1.08	0
callProxy1	3	29	141	0.35	1.42	5.44
callArgs	25	40	172	0.72	1.55	0.41
inline	1	5	15*	0.41	0.26	5.43

Conclusions: Chrome > Firefox > IE 7, function.call > function.apply, any of the class or closure based approaches worked about the same, regardless of the inheritance mechanism. the dojo.extend style seems slightly faster to invoke, but for any real problem i don't think it's worth worrying about. dojo.hitch and function.apply seem massively slow, especially when combining arguments from the hitch and the invocation. function.call is much faster, and a custom function as a proxy is faster yet - taking about twice as long as directly accessing the source object

* my tool reported mostly 0 msec on IE 7, but every by-hand test that i did was 15 or 16 msec. pretty sure that the delta in Date() isn't working in tight loops