Re: Jolt, statics?

Hi Gavin,

Am 09.04.2008 um 02:32 schrieb Gavin Romig-Koch:
>        http://people.redhat.com/drepper/cpumemory.pdf

that looks like a very interesting reference, thanks a lot.

> There are probably other papers out there more specific to  
> implementing very late bound languages, but this isn't an area I've  
> looked at much.

I presume that if inline caching was really that much of a bugger, it  
would not be used at the degree it is in (probably amongst many  
others) the VisualWorks Smalltalk VM, which was implemented and is  
maintained by very smart people.

The id object model accompanying Ian and Alex' paper on the object  
model has both global and inline caching, and having inline caching  
alone improves performance more than having global caching alone - at  
least that's what the very informal measurements I just ran yield.

>> Related question: does threaded interpretation still make sense  
>> these days, what with all those sophisticated branch prediction  
>> units around? Again: are there reliable sources?
> Oh, by "multi-threaded" I meant multiple threads of execution  
> running the same machine code (as in POSIX threads), not threaded  
> interpretation (as in one of the ways to implement Forth like  
> languages). [...]

Ah, I was not at all about multithreading. I saw the question of  
threaded interpretation in conjunction with the question of inline  
caching. Both are mechanisms that were originally devised to help CPUs  
in doing their jobs better without facing too many branch  
mispredictions or cache misses, respectively.

> But you might find the answer to your question in Anton Ertl (and  
> others have done):
>     http://www.complang.tuwien.ac.at/projects/forth.html

I know their work; unfortunately, there do not seem to be very recent  
results produced on, say, Pentium IV CPUs. (For one paper that  
appeared in 2003, they made measurements regarding branch prediction  
and threaded interpretation, but those were run on a simulated MIPS.)

>
Best,

Michael

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