Is it possible to run Parallel Computing inside a GUI with more than two cores?

Hi,

i've spent some time building a nice little GUI for measurement evaluation of INCA files.

Before building that GUI, I wrote a script for my computations using the Parallel Computing Toolbox. I started my workers using

N = 4; 
myCluster=parcluster('local'); 
myCluster.NumWorkers=N; 
parpool(myCluster,N);

to make sure that all 4 CPUs were being used. So far so good everything worked fine.

Now when I try to run that script by calling it via a pushbutton, it suddenly uses 2 workers only. It doesn't change anything if I start the parallel pool manually before using the GUI or if i embed the code above inside the script or the GUI callback function. The job manager tells me that 4 workers are online and working but the symbol on the bottom left only shows 2 of 4 green bars and CPU usage is only at about 50%. When starting everything without the GUI, there is roughly 95% CPU usage and all 4 bars are green.

Do you guys know any solution?

Another issue is that the workers slow down their computations after a couple of days. It looks like single cores even stop working (according to CPU usage). Iteration time of the parfor loop increases from 2 hours to 3 and more.

Thanks in advance :)