processus time double after fews seconde

hi,

my application use android java JNI to process camera vidéo in real time. The C part use openCL and multicore threading with médiatek 9200+ and mali G715.

Something strange append with the application. After fews seconde of processing, 70-80 frames, i go from 60-70ms per frame to 140-160 per frame.

What i am doing :

1) i do some kernel to conver YUV and extract data

2) Then i procees the extracted data with CPU multicore threading(4 thread at the time) 7 time.

3) Then i use kernel again to extract data and send it back to Java.

If i remove all the CPU work, the GPU time remain stable between 20ms at the begining(70-80 frames)  to 40-45. But with the CPU work time increase dramaticly after 70-80 frame using the same amount of input data. The same problem appened with my old mali g72 after 20 frames.

I tried to use streamline, but as i run windows7 i cannot have the analizer, how just run from windows10. But i can get the graph and i remarked a strange activity on the GPU.

1) the Mali Memory Read Latency after to get red after the 70-80 frames. (it show 25 mega beats ?)

2) the Mali geométry culling rate start to ocsillate. (it show 100%)

3) the Mali geométry efficiency start to ocsillate. (it show 3 trheads)

4) Mali Early ZS rate is red

and many other thing start to ocillate. But Device Thermal State is 100% green.

in fact after 70-80 frames a lot of thing start to ocsillate.

And streamline is to complicated for me. there is too much things to know and anderstant. I do not have the time.

So i am wondering if it could be possible for an expert to analyse it.

As i said i had the same problem on old maliG78 so at some point there is something that goes wrong using in alternance GPU-CPU-GPU. In one of my post about SVM someone told me that using GPU and CPU was not a good odea. But i cannot do with GPU what i am doing with GPU. Or i do not know how to do with GPU what i am doing with CPU. At some time i need to procces data with CPU.

thanks for the help.