PeakDetector very slow on labview 8 ...

[nicoco]

I have done a program that use labview PeakDetector module and i have compared the execution speed between labview 7.1 and labview 8.
The vi is 3 times faster on labview 7.1 !

Test it (you must have labview 8 and labview 7.1, and use Windows taskmanager to mesure the rate of CPU activity), and give-me your results ... (or if you have a solution to have better speed exection on labview 😎

PS : My computer is a PC with a Pentium D 920.

Thank,
Nicolas ROUSSEL

[Kenny_K]

I see what ou are saying about the CPU usage, but I think that you also have to look at the memory usage.  LabVIEW 7.1.1 uses 43,524k of memory and LV 8.0.1 uses 24,568k, on my computer.  I am on a computer with 3.4 GHz P$ with 2 gb of ram.

Although LV 8 uses more cpu time, it uses hlaf the memory so there is a trade off there.

I am not sure how you can make the CPU time decrease or the memory increase for LV 8.  The programming is the same in both your vis.  I will do some more tsting when I get a chance and reply back

Kenny

[Kenny_K]

Ok, I ran some tests on the time it took to execute the vi for 200 iterations.  The time is the start time minus the final time using the tick count.vi  The time is in ms.

LV 7.1         LV8.0

10406         10579
10310         10880
10332         10992
10356         10875

So it is obvious that 7.1.1 is slightly quicker than LV 8.0, but I dont think that it would make too much of a difference unless you need a really time critical program. 

Kenny

[kamalb]

Hi

I have tested and i have the same results:

                              LV 7.1                  LV 8.0
100                  
300
500
700
1000

[kamalb]

Hi
Sorry...
the result of my test (time in ms). It is the same....

itération:     100     300       500      700      1000
LV7             5236  15554   25814   36194  51612

LV8             5342  15934   25638  36469  52165

Kamal
NIF

[nicoco]

I'm surprised, because i have contacted ni support, and they have confirmed to me that it's a bug in labview 8.
My programm works on labview 8, but i can have only two inputs (6 inputs on labview 7.1 !!). The problem is peakdetector, i'm sure :
I have find one solution : i have imported the lvanlys.dll v7.1.0.17 from labview 7.1 (peakdetect use this library) in labview8, and my program work correctly !

[kamalb]

Hi
I confirm you the result i have given...
I use LV 7.1 and LV 8.0 (without any patch). I use French versions.
Maybe there is a bug with the english versions?? Or the bug occurs sometimes??
But my computer doesn't reproduce the problem...

Kamal
NIF

[nicoco]

I have one question for you test :
What is the in input in peakdetct ?
Peakdetect must do a fit with real sample, else you're test is not good.

Could-you give to me your version of labview 8 lvanlys.dll

I use the french version too,

Thank

[kamalb]

Hi
X= an array the array by default
seuil=0,9....
I am not authorized ti give dll sorry...

Kamal
NIF

[nicoco]

I have done the test with a PIV 3 Ghz, and i find always the same prblem.

But if you use the two programs in my forum question, it's logical that you find the same number of iteration.

The problem is the free time cpu during the program execution. The programm take 3 times more in labview 8 (press alt-ctrl-sup in windows to see the cpu time) than in labview 7.1.