[geeks] Carly Fiorina to enter politics? This nation is doomed...

[Francisco Javier Mesa-Martinez]

On Thu, 9 Sep 2004, Mike Meredith wrote:

> > Depends how much of the chip is being used on trying to keep the
> > (This would be for server/scientific stuff obviously - "typical
> > desktop" machines would not do well with such a design.)
>
> Being dumb here, why wouldn't it work well on a desktop ? My Blade2000
> has around 10 active processes all sucking up CPU time at the moment,
> and it's almost idle except for creating YAZ ("yet another zone").

The main problem is that adding more cores to a single processor package
has some serious nasty side effects, mostly the fact that there is a limit
in the number of pins (and their bandwidth) that go out of chip. So you
will have to share a lot of the IO BW for that package among the chips
present, this leads to the possibility of very underutilized silicon.

Memory is going ot be your main bottleneck, you may apply some parallelism
to certain number of applications which you know they memory patters well
enough to taylor your interconnection accordingly. I.e. if they are very
cache friendly you may get a boost out of a large chache near each core
which reduces the overall BW requiremenets. However in desktop
applications funny things happen, mostly that even though you may have
100's of threads present in your system... only a few of them account for
90%+ of the overall processing. Plus a lot of multimedia applications have
very shitty cache performance (i.e. very little data reuse)