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[Caml-list] FP's and HyperThreading Processors
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Date: 2003-06-13 (08:06)
From: John Max Skaller <skaller@o...>
Subject: Re: [Caml-list] FP's and HyperThreading Processors
David McClain wrote:

> I suspect, but have yet to prove, that the low utilization is due to a low
> CPU to memory bandwidth and to the failure of the L1 and L2 caches to supply
> needed operations and data to the CPU. This, I would hypothesize, is going
> to be demonstrated by any language that prefers fresh memory allocation for
> results, e.g., OCaml, ML, Lisp, Smalltalk, etc.

Well, I did think Ocaml used a generational collector
that recycled 'young' memory fast. Perhaps the
'youthfulness' can be tuned down to the L2 cache size?

FYI: its my understanding there is a new trend.
Processor caches in multi-processor systems are
a bad idea. Instead, the memory chips should have
caches on them. I believe, quite a few do now:
DRAM with an SRAM cache.

Now that should actually mean that using
'fresh' memory is actually the *fastest* method,
since it tends to distribute the load over all
the memory chips. In particular .. writes become
much faster than reads (since all random writes
get cached, whilst some reads still have to wait
for the main store).

John Max Skaller,
snail:10/1 Toxteth Rd, Glebe, NSW 2037, Australia.

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