[Gllug] On Linux, fast, it is

[Nix]

On 13 Jun 2002, John Hearns uttered the following:
> On Thu, 2002-06-13 at 13:38, Nix wrote:
>> GCC and the binutils have support for it, but I don't know how good/
>> complete that support is.
>> 
> Indeed.
> I'm very interested in the 128-bit vector registers,
> which have obvious applications in image processing etc.

If there isn't support for these, there will be soon --- but rudimentary
only, attributes to put things into specific vector registers and the
like.

It'll be a while (a long while, if ever) before GCC does any significant
amount of vectorization :)

> I remember doing a tiny bit of work  on vectorising.
> IBM brought out a vector unit for their 3090 series, and were 
> promoting it. The Glasgow Uni group I was in  were asked to test it out.
> I compiled up some of our Monte Carlo codes, and in fact IIRC things
> went slower.

This is *extremely* common with distributed or parallelized simulations :)

You're classed as lucky if you're wasting only half the time of your
nodes in comm overhead (blocking/redoing changed work/otherwise doing no
useful work).

-- 
`What happened?'
                 `Nick shipped buggy code!'
                                             `Oh, no dinner for him...'

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