Getting a periodic pause

[Rick N.]

My applilcation reads and processes sensor data (stereo vision cameras and flash ladar units) at 10Hz. The program reads the data, tracks a series of targets, and displays the results. Periodically (generally 2-3 minutes, but can be as long as 17 minutes and as short as 30 seconds) the loop pauses for 2.25±0.1 seconds.

I set up a test using random number generator to create a 100mS loop. It shows an occasional pause of 0.4sec. The period between pauses varies between 2 and 43 minutes.

Does anyone now what might be causing the periodic pause, and how to stop it?

Thank you.

[Ben]

"Does anyone now what might be causing the periodic pause, and how to stop it?"

Well not with the info you provided, but I can get you started.

First!

It is not unusual for Windows to go off into "lala-land" ocationally. LV-Real-time is designed to prevent this.

BUt back your you issue.

Watch the Task manager while your test is running.

Choose the Processes tab and click on the "CPU" collumn to see what is going on durring teh pause.

Upadte us when you learn more.

Ben

Message Edited by Ben on 07-25-2006 10:45 AM

[Rick N.]

We looked at the task manager before. Generally the LabView process and the idle process split the cpu time 86%/13% (1% to others). During the pause, the idle process takes 95+%.

[Ben]

Pauses and the CPU goes to 0, hmm.

This could be an I/O wait.

This could be due to memory requirements growing and LV is going into a Page fail wait state. Do you see the LV process page faulting when this happens?

Similarly writting to files coudl do this.

Could post an image of the simple tester so we can be of greater assistance?

Trying to help,

Ben

[Rick N.]

I want to thank y'all for your help. We traced the problem to hardware. Our firewire board can access only one port at a time. Simultaneous requests caused the 2.25s pause. Thanks again.