[Beowulf] CCL:Question regarding Mac G5 performance (fwd from mmccallum@pacific.edu)

Joe Landman landman at scalableinformatics.com
Thu May 20 13:23:36 PDT 2004


On Thu, 2004-05-20 at 02:05, Michael Huntingdon wrote:
> I've spent some time sifting through the attached numbers. Though not each 

Any paper that starts out praising spec as a "good" predictive benchmark
is suspect.  Benchmarking is difficult to do right, in large part
because of deceptively simple scoring functions (time, frequency (not of
the CPU, but number of iterations per unit time), ...).  

Further, looking these over, I did not see much of a discussion (though
it is implied by the use of certain compilers) of the effects of things
like SSE2 in the P4, memory alignment, 32/64 bit
compilation/optimization, use of tuned libraries where available...
Given the sheer number of machines tested, it is unlikely that they used
up to date compilers (latest gcc's are better than earlier gcc's for
performance), or recompiled the binary for all the different platforms
to run native.  The ifc results seem to indicate that they used SSE2 on
P4's but probably used plain old 32 bit code on Opterons.

> lends itself to hp Itanium 2, there appears to be a very balanced trend. 

... in a specific set of operations relevant for specific classes of
calculation.

Not everyone in HPC does matrix work, eigenvalue extraction, etc.  Some
of us do things like string/db searching (informatics).  There, the
numbers look quite different.

[... snip ...]

-- 
Joseph Landman, Ph.D
Scalable Informatics LLC,
email: landman at scalableinformatics.com
web  : http://scalableinformatics.com
phone: +1 734 612 4615




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