Re: data-crunching in guile

[Neil Jerram <neil@ossau.uklinux.net>]

Andy Wingo <wingo@pobox.com> writes:

> I don't have Neil's mail open here, but my thought was this: getting a
> fast VM is a dark art of feeling and instinct, My feeling is that a VM
> is fast if it fits in the CPU's cache: the instruction cache and the
> data cache. The data cache means that smaller code is better, hence my
> resistance to word-sized instructions. The instruction cache means that
> the VM itself should be small -- but if the code for vector ops is all
> "at the end" of the VM, then only code that uses vector ops pays for the
> increased "cache footprint" of the VM.

Thanks, I see now.  But presumably even VM code will frequently call
out to primitives all over libguile, won't it?

I completely agree that small code size can be important for
performance, but I doubt that it is the size of the VM on its own that
matters.

(Or am I still not understanding what you mean?)

> But like I say, all this is instinct, which may well be wrong.

Me too!

   Neil