[Beowulf] SGI to offer Windows on clusters

Ashley Pittman ashley at quadrics.com
Thu Jan 18 07:20:22 PST 2007

On Thu, 2007-01-18 at 08:17 -0600, Richard Walsh wrote:
> Ashley Pittman wrote:
> > On Wed, 2007-01-17 at 08:50 +0100, Mikael Fredriksson wrote
> >> Yes, it is.  And more so if this cluster/LAN can also utilize som type
> >> of "MOSIX" system.  This will substatially increase the throughput of
> >> "standard serial" processes.
> >>     
> >
> > I find this statement hard to comprehend, how can any OS substantially
> > improve throughput of jobs unless what it replaces is incredibly
> > deficient in some way?  The limiting factor on clusters is the speed of
> > the hardware, even if some OS magically manages to be say 50% more
> > efficient doing it's bit than another OS it's still only a tiny percent
> > of time used, substantial improvements in job throughput can only come
> > about from better parallel algorithms, better code or faster hardware.
> >
> >   
>      While I agree with this argument, especially at small scale, at 
> very large scale operating
>      system derived load imbalance (so-called skew, due to the random 
> nature of system
>      call driven interrupts) can destroy scalability, and thus 
> efficiency.  This is worth mentioning,
>      although I would not expect Windows to improve on Linux in this 
> context.  You need
>      a light-weight kernel like Catamount to reduce skew.

Absolutely, it's one of the more interesting challenges facing large
scale cluster development currently.  Large scale in this context is
>1000 nodes however, I don't think this is the market Microsoft is

I could of course argue that the answer to the skew problem is going to
be a algorithmic one which would mean my previous statement holds.


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