Re: [TUHS] PDP-11 legacy, C, and modern architectures

[Warner Losh <imp@bsdimp.com>]

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On Thu, Jun 28, 2018 at 8:56 AM, Larry McVoy <lm@mcvoy.com> wrote:

> On Thu, Jun 28, 2018 at 10:43:29AM -0400, Perry E. Metzger wrote:
> > On Thu, 28 Jun 2018 10:15:38 -0400 "Theodore Y. Ts'o" <tytso@mit.edu>
> > wrote:
> > > I'll note that Sun made a big bet (one of its last failed bets) on
> > > this architecture in the form of the Niagra architecture, with a
> > > large number of super "wimpy" cores.  It was the same basic idea
> > > --- we can't make big fast cores (since that would lead to high
> > > ILP's, complex register rewriting, and lead to cache-oriented
> > > security vulnerabilities like Spectre and Meltdown) --- so instead,
> > > let's make lots of tiny wimpy cores, and let programmers write
> > > highly threaded programs!  They essentially made a bet on the
> > > web-based microservice model which you are promoting.
> > >
> > > And the Market spoke.  And shortly thereafter, Java fell under the
> > > control of Oracle....  And Intel would proceed to further dominate
> > > the landscape.
> >
> > I'll be contrary for a moment.
> >
> > Huge numbers of wimpy cores is the model already dominating the
> > world.
>
> Got a source that backs up that claim?  I was recently dancing with
> Netflix and they don't match your claim, nor do the other content
> delivery networks, they want every cycle they can get.
>

Well, we want to be able to manage 100G or more of encrypted traffic sanely.

We currently get this by lots (well 20) of not-so-wimpy cores to do all the
work since none of the offload solutions can scale.

The problem is that there's no systems with lots (100's) of wimpy cores
that we can do the offload with that also have enough bandwidth to keep up.
And even if there were, things like NUMA and slow interprocessor connects
make the usefulness of the boatloads of cores a lot trickier to utilize
than it should....

Then again, a lot of what we do is rather special case, even if we do use
off the shelf technology to get there...

Warner

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