LV performance with Dual core processors

[KERV]

Hi,

I have tested the vi describe in the note "LabVIEW and hyperthreading"

http://zone.ni.com/devzone/conceptd.nsf/webmain/01F2E634710FB8E486256E2900586D41

on a Pentium D 940 dual core 3,2GHz PC.

The results are strange.

With one for loop (testperf2.vi) the execution time for 400000 iterations is 3,4 s

With two parallel loop (testperf3.vi) the execution time for 400000 iterations is 7 s

Is I set the Affinity to CPU 1 only the execution times are both about 3,5 s !

I don't understand, can somebody explain these results ?

Thanks

[mfitzsimons]

It seems to me that perf3 is processing twice the data so you are seeing time to execute * 2 threads + overhead.  If I am wrong I do apologize in advance.

I ran perf2 on my 3,2 GHz PC using the progam defaults and I get 390 mSec that is about 10x faster than you are reporting.

A final note it that i am personally looking into purchasing a Core Duo laptop PC in the very near future.  Is there any performance data for the difference Core Duo Processors?  The T2300, T2400, T2500, and T2600s.  Am I wasting money with this technology?

Matt

[KERV]

Hi Matt,

Thanks for your test.

In perf3 each thread proccess half data.

The given process time is given for 400000 (the default value is 100000).

If I set the "Affinity" (In Windows task manager) to CPU1 or CPU2 (not both) (like a single core processor), the process time is better than with both CPU !

Thanks again

[mfitzsimons]

Sounds like we need someone with access to a buch of PCs to do some benchmarking of performance.  Any volunteers out there?  Agree, your numbers do not make sense.

Matt

Message Edited by mfitzsimons on 06-01-2006 12:00 PM

[Ray.R]

I'm also interested in this.

My super-duper Hyperthreading single core, filled to the teeth with warp engine 3GHz PC.... is slower than my regular 256MB, 2.4GHz PC...

And I recently, I upgraded my wife's PC with an AMD (finally switched camps) 1.8GHz and it kicks the butt off both my PC's!!!!

I am looking at newer / faster technologies, including the dual core, but I don't believe in the forecasted increase in performance.  Windoze doesn't support dual core.  Most applications do not either..  However, I would be interested in learning if there are improvements when using LV...

---- curious  ----

(PS:  then there are games... but who has time for that???)