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<DIV><FONT size=2>Hi Everyone,</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2> I am researching a proposal to build a
cluster. Its primary purpose in life will be to perform FFTs
(spectragrams) on large acoustic records. </FONT><FONT size=2>I have
tentatively chosen the DEC DS10L with a 466 MHz 21264 processor because of its
FPU performance and its form factor. </FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2> Unfortunately, I can't rush out and buy 40
DS10L's in order to see how fast I can create spectragrams. So I'm trying
to come up with a reasonable estimate. I know that the DS10L is currently
466 MHz and will be at 600 Mhz before I buy them so I have a built in fudge
factor already :)</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2> I plan on using the FFTW package from <A
href="http://www.fftw.org">http://www.fftw.org</A> and they have compiled some
benchmarks at <A
href="http://www.fftw.org/benchfft/results/alpha467.html">http://www.fftw.org/benchfft/results/alpha467.html</A>.
That leads me to believe that one box can basically sustain 200 MFLOPs.
Now, I am making an assumption that distributing FFTs among nodes is very
balanced (scaleable? parallelizable? whats the term I'm looking for
here?) and therefore it will scale well (note, I am not trying to do a single
FFT distributed among nodes, I am breaking up the stream into blocks).
This would be (best case) 40 * 200 = 8000 MFLOPS, and I'll use a scaling factor
of 0.8 and call it an aggregate performance of 6,400 MFLOPS.</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2> Is this completely specious
reasoning? Am I completely out of the ballpark?</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Regards,</FONT></DIV>
<DIV><FONT size=2></FONT> </DIV>
<DIV><FONT size=2>Gary Huntress</FONT></DIV>
<DIV><FONT size=2>former owner of "Beosaurus" </FONT></DIV>
<DIV><FONT size=2><A
href="http://superid.virtualave.net/beowulf.htm">http://superid.virtualave.net/beowulf.htm</A></FONT></DIV></BODY></HTML>