[Cryptography] [FORGED] Re: Speculation considered harmful?

[John Levine]

In article <1515485412892.49422 at cs.auckland.ac.nz>,
Peter Gutmann  <pgut001 at cs.auckland.ac.nz> wrote:
>John Levine <johnl at iecc.com> writes:
>
>>VLIW isn't just wide microcode.  It's a combination of wide instructions with
>>compilers that use aggessive techniques to keep the hardware controlled by
>>wide instructions busy.
>
>I think you mean:
>
>  VLIW isn't just wide microcode.  It's a combination of wide instructions
>  with compilers that no-one can ever quite manage to write that take
>  advantage of them.

The compilers actually worked pretty well, give or take the memory scheduling stuff.

>There's a good reason why vendors went deep rather than wide to make things go
>fast, it was, and still is, the easiest way to get performance.

Agreed.  I think the reason is that it turned out that a lot of the
hazard avoidance stuff that trace scheduling was intended to avoid
turns out to be doable on the fly in hardware, which makes it easier
to keep those deep pipelines busy.

R's,
John
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