[Beowulf] Intro question

[Lawrence Stewart]

Bogdan Costescu wrote:
> On Fri, 5 Dec 2008, Joe Landman wrote:
>
>> The MDGrape guys might have a thing or three to say.  They have been
>> demonstrating some pretty awesome performance for years.
>
> True, but my impression was that they were focused on getting the most
> performance from one unit, while the DEShaw approach factored in a
> high degree of parallelization from the beginning.
>
> I've heard the talk in Dresden earlier this year and I liked hearing
> about an idea that I've also had some time ago but not heard talking
> about on this list: interconnect hardware being able to DMA directly
> to/from CPU cache. I don't know how useful such a feature is for a
> general purpose interconnect (or MPI library) but it certainly fits
> well in the specialized frame of molecular dynamics (or rather, of how
> MD is implemented today).
>
Well <of course> the NIC should read from cache or update the cache if the
data happens to be there. Don't all well designed I/O systems do that?

A mathematician woke up one night to find his wastebasket on fire.  He
poured water into it and went back to sleep.

The next night, he woke up again to find the desk lamp on fire, so he
put it in the wastebasket, reducing the issue to a previously solved
problem.

Flushing caches for I/O is like that.

-- 
-Larry / Sector IX