[Vm-dev] ARM Cog progress

tim Rowledge tim at rowledge.org
Sun Jun 7 04:13:59 UTC 2015

If I build on the pi2 with -O1 instead of O2 the vm works apparently as well as it did early last week on O2. At least this means I can keep working!

Once I have a running version I can run the SUnit test suite except for the FloatMathPluginTests which blow up several alternate Earths every time. The interesting observation this evening is that after starting the tests on one of my Pi B+’s and watching for five minutes or so to see if it would be happy, I started the tests on one of my Pi2’s. Within a few minutes (yes, I‘m being oh so precise, I know) the Pi2 had caught up and passed the number of tests the B+ had got to. A few minutes later it was waaaay ahead.

This is interesting because in raw low-level benchmarks the Pi2 isn’t very much faster (~20-30%) than the B+ units. So I’ve just run Eliot’s favourite benchmarks, the ShootoutTests in the CogBenchmark package. Comparing B+ to 2 we see
nbody	415	168	2.5X
bintree	88	46	1.9X
chredux	313	86	3.6X
thread	335	111	3X

Remember, this is the same vm, same image.

tim Rowledge; tim at rowledge.org; http://www.rowledge.org/tim
Useful random insult:- An 8086 in a StrongARM environment.

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