gpib decrease performance

[Thez]

Hi,

I encounter a significant loss of Gpib performance, for one year now !

I have written a Gpib application (in C++) which works fine since we use

Visual C++ 2005 Express Edition and its compiler.

Now, each client that uses my Gpib application consumes a lot of CPU

something in the range 5% up to 15% (if polled).

I took a look here :

http://digital.ni.com/public.nsf/allkb/DD67839852DCF8FA8625768D007A8474 

and tried to update the ni4882 driver found here :

http://joule.ni.com/nidu/cds/view/p/id/1529/lang/en 

But, I have no success. I do not know where is the problem and why

that consume a lot of CPU.

My configuration :

- Windows 2000 SP4 on a CompactPCICrate

- Ni-488.2 v2.2.73

- Gpib board for CompactPCICrate

- Visual C++ 2005 Express Edition

Any help should be appreciate.

Best Regards

Xavier 

PS : I also tried a simple main which call first ibdev and

then enter an infinite loop which call ibwrt (sending "*IDN?") and ibrd.

This consumes 10% of the CPU !! 

PS 2: My application compiled with Visual C++ 6 under Windows2000

works fine.

[Snowman 6008]

Thez,

I have some questions about the differences between these two computers, and programs. Please give me some more information so that I can better help you find what may b e causing this error:

1. What is different between the computer that works and the computer that doesn't ? You mentioned you compiled a program in different versions of visual studio, but are the two computers using a different service pack of windows, Processor, versions of 488.2 installed, etc.
2. How much processor does the computer that "works" consume when running the "*IDN?" in a loop? We need to know your comparison for what works and what doesn't . 
3. Is your Visual C++ managed code, or unmanaged code? Managed code can be more intensive to processing, though typically it shouldn't drop your performance this much. 

[Thez]

Richard,

Thank you for your response.  

1) The main differences between the two computers :

- One is running Windows2000 Pro SP4 and the other a WindowsXP Pro Version 2002, both use the same version of 488.2 the v2.42.

I do not know the Processor type, version but if it is important, let me know. I will try to find them asap.

2) The computer that works, consumme between 0 and 2% of CPU and it is the application compiled with Visual C++ 6.0 under Windows2000, and using

the ni488.2 v2.42

Now we migrate our CompactPCICrate's OSs to WindowsXP and we use Visual Express 2005. The problem appears with this compiler. Using ni488.2 version 2.42 or the last one version 2.73 does not change the CPU charge. The application use between 10 to 30%.

3) I do not know the Visual C++ is managed or not. How can I know this ?

I have to do some tests of performance and I will post the results as soon as possible.

Let me know if you need more informations.

Regards,

Thez