Why vi runs in subpanel slower than stand alone or as a subvi

[lshi]

I have an image acquisition vi which can run stand alone. It usually takes  ~60 ms to capture each image (pretty constant by time counter). The problem is that when I put it in to a simple subpanel (using reference -> run vi) with only one stop event, it slowed down by 10~40 ms. However when I used this acquisition vi as a subvi, the counter gave me almost the same time as running stand alone. I do like the subpanel way but couldn't afford the slow down. Is there any way to improve it?

[Christian Mergl]

How do you determine the timing?

I was running a little test now with a USB Cam and just a Snap as standalon VI as well as calling it via SubPanel. In my case the results where almost the same.

Christian

[lshi]

I finally found out the problem was the display. I accidently ran the main vi in its block digram with front panel minimized. In that case, I got the same timing. So I froze the display in my subvi when the acquisition began and the problem solved. I guess the subpanel could not catch up with the speed of updating the subvi display.