[Vm-dev] RoarVM: The Manycore SqueakVM

Levente Uzonyi leves at elte.hu
Sat Nov 6 15:26:48 UTC 2010


On Thu, 4 Nov 2010, Stefan Marr wrote:

>
> Hi Bert:
>
> On 04 Nov 2010, at 20:20, Bert Freudenberg wrote:
>
>>>> So RoarVM is about 4 times slower in sends, even more so for bytecodes. It needs 8 cores to be faster the regular interpreter on a single core. To the good news is that it can beat the old interpreter :)  But why is it so much slower than the normal interpreter?
>>> Well, one the one hand, we don't use stuff like the GCC label-as-value extension to have threaded-interpretation, which should help quite a bit.
>>> Then, the current implementation based on pthreads is quite a bit slower then our version which uses plain Unix processes.
>>> The GC is really not state of the art.
>>> And all that adds up rather quickly I suppose...
>>
>> Hmm, that doesn't sound like it should make it 4x slower ...
> Do you know some numbers for the switch/case-based vs. the threaded version on the standard VM?
> How much do you typically gain by it?

If threaded means gnuified (jump table instead of the linear search), then 
it gives ~2x speedup for the standard SqueakVM.


Levente

snip


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