Re: Why Alpha? (aka: is it worth it?)

["Adam C. Powell, IV" <adam powell nist gov>]

Adam Wiggins wrote:

>    However, I've heard a lot of people having problems with what seem like
> pretty basic things to me; eg, getting Netscape/Mozilla to run properly (it's
> buggy enough on the x86!), or Gnome running slowly.  There are also some small
> [snip]

Update: GNOME is no longer slow.  The problem was a kernel bug in 2.1.125 that
caused poll() to suck CPU.  As of 2.2.0-pre6 (and -final), it works beautifully.

One tiny correction: including load/store, alpha 21164 can execute up to *four*
floating-point instructions per cycle.  Which is how Goto's gemm inner loop gets
so close to two floating-point *operations* per cycle- one add and one multiply.

Also, Daniel, does your high regard for SGI Origin take price into
consideration?  We've found that Origin nodes cost roughly five times as much as
alphas with roughly the same fp performance, and for matrix multiply and related
(e.g. LU decomposition) our alphas are about four times faster!  And SGI memory
prices are absolutely outrageous.  If they were similarly priced, the Origin's
memory architecture for SMP might be worth the speed penalty of individual
processors, but they're not...

Zeen,

-Adam `Cold Fusion' Powell, IV http://www.ctcms.nist.gov/~powell/ ____
USDoC, National Institute of Standards & Technology (NIST)  |\ ||<  |
Center for Theoretical and Computational Materials Science  | \||_> |