28 Jun
2018
28 Jun
'18
3:39 p.m.
On 28 Jun 2018, at 15:58, Larry McVoy
<lm(a)mcvoy.com> wrote:
You completely missed my point, I never said I was in favor of single
cpu systems, I said I the speed of a single cpu to be fast no matter
how many of them I get. The opposite of wimpy.
And this also misses the point, I think. Defining a core as 'wimpy' or not is
dependent on when you make the definition: the Cray-1 was not wimpy when it was built, but
it is now. The interesting question is what happens to the performance of serial code on
a core over time. For a long time it has increased, famously, approximately
exponentially. There is good evidence that this is no longer the case and that per-core
performance will fall off (or has fallen off in fact) that curve and may even become
asymptotically constant. If that's true, then in due course *all cores will become
'wimpy'*, and to exploit the performance available from systems we will *have*
to deal with parallelism.
(Note I've said 'core' not 'CPU' for clarity even when it's
anachronistic: I never know what the right terminology is now.)