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Re: data-crunching in guile
From: |
Neil Jerram |
Subject: |
Re: data-crunching in guile |
Date: |
Thu, 25 Jun 2009 23:47:47 +0100 |
User-agent: |
Gnus/5.11 (Gnus v5.11) Emacs/22.2 (gnu/linux) |
Andy Wingo <address@hidden> 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
Re: data-crunching in guile, Andy Wingo, 2009/06/26