[Info-vax] What choices are available to the OpenVMS Process Scheduler once all the CPUs are in use?

[Carl Friedberg]

Of course I know the 782 was ASMP, that was a (bad) joke. Hyper-threading
is a nice way to up the marketing value by doubling the number of core
CPUs, but I doubt that VMS users will see much, if any benefit; and
possibly there will be a performance penalty. It can't hurt to test a
specific environment, as it would be hard to predict IMO.

Whatever the benefit of hyper-threading, I doubt anyone will ever double
their throughput by turning it on. YMMV.

Carl

On Wed, Feb 10, 2016 at 2:09 PM, abrsvc via Info-vax <info-vax at rbnsn.com>
wrote:

> On Wednesday, February 10, 2016 at 1:40:06 PM UTC-5, Carl Friedberg wrote:
> > I would try turning off hyper-threads. I've never seen it make more than
> a
> > few percent better perofrmance, and it can make things worse. Remember
> the
> > VAX 782 (with 2CPUs, performance, IIRC, was of order .8 VUP. Hoff will
> > remember better.
> >
>
> I remember that well.  There was an analysis tool that would indicate
> whether or not your particular application would benefit from the
> additional CPU.  Please note that the 782 was an ASMP machine
> (Asynchronous) and would only benefit compute bound applications.
>
> Dan
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