Here is an alternative (a bit more precise) test case: http://jsperf.com/float64-vs-float/2
-- Vyacheslav Egorov On Tue, Jan 17, 2012 at 10:46 AM, Daniel Clifford <da...@chromium.org>wrote: > All the examples are optimized by Crankshaft. However, in the Float64Array > case, storing the intermediate values in the array forces a memory access. > When you use local variables, it's much faster, since the intermediate > double operations and local variables are stored in registers, avoiding > memory accesses and triggering only a single boxing operation at the > "return". > > Danno > > > On Tue, Jan 17, 2012 at 2:01 AM, Joseph Gentle <jose...@gmail.com> wrote: > >> I tried a simple test on jsperf to see if I can get a speedup from >> float64 arrays: >> >> http://jsperf.com/float64-vs-float >> >> In this test, using float64 arrays end up slower than just using normal >> variables. JSPerf tests are only run for a few seconds - is that long >> enough for v8's optimizer to kick in properly? - Or is that benchmark >> correct, and I'm just missing something? >> >> -J >> >> >> >> On Friday, 30 December 2011 07:33:14 UTC+11, Vyacheslav Egorov wrote: >>> >>> 2) There are fields mutated in the loop that contain floating point >>> values. This currently requires boxing (and boxing requires heap >>> allocation, heap allocation puts pressure on GC etc). I wonder if you can >>> put typed arrays (e.g. Float64Array) to work here. >>> >>> -- >>> Vyacheslav Egorov >>> >>> -- >> v8-users mailing list >> v8-users@googlegroups.com >> http://groups.google.com/group/v8-users >> > > -- > v8-users mailing list > v8-users@googlegroups.com > http://groups.google.com/group/v8-users > -- v8-users mailing list v8-users@googlegroups.com http://groups.google.com/group/v8-users
