Some remarks:
- Such loop can put lot of stress on the CPU. You can do lot of loops in 200ms. That's one case where delay() can help.
- With your code, you read the bytes even if nothing is available...
- The vims_control.available() printed out can be different from the one in the while loop... That's two distinct calls of the function at different times...

Hi,
thanks for your comments, I knew there were a few defects in that part. It's just I never figured out all of them AT ONCE :). And since it's at the heart of my program, it should be more well written.

Here's some modifications I made, effectively reducing java load from 99-100% to 70% and yielding more robust code.

1.     public int read_control_head() {
2.         byte answer[] = new byte[8];
3.         if(read_control_timeout(answer, 200) == 0) {
4.             return 0;
5.         }
6.         else {
7.             return Integer.parseInt(new String(answer));
8.         }
9.     }
10.     // network read with timeout
11.     public int read_control_timeout(byte answer[], int delay) {
12.         int timeout = parent.millis() + delay;
13.         while( parent.millis() <= timeout) {
14.             if(read_control_nb(answer) != 0) {
15.                 return answer.length;
16.             }
17.             try {
18.                 Thread.sleep(5);
19.             } catch (InterruptedException e) { }
20.         }
21.         return 0;
22.     }
23.     // blocking network read: returns when the bytes are found
24.     public int read_control_blocking(byte answer[]) {
25.         while(vims_control.available() < answer.length) {
26.             try {
27.                 Thread.sleep(5);
28.             } catch (InterruptedException e) { }
29.         }
30.         vims_control.readBytes(answer);
31.         return answer.length;
32.     }
33.     // non blocking network read: returns null if
34.     // data is not there yet.
35.     public int read_control_nb(byte answer[]) {
36.         int available;
37.         if((available = vims_control.available()) < answer.length) {
38.                      return 0;
39.         }
40.         else {
41.             vims_control.readBytes(answer);
42.             return answer.length;
43.         }
44.     }

I'll put this code on the bigger computers tomorrow and see if they behave better.

Notice I didn't use delay() because I call these methods while in setup(), and because it will be removed from p5 2.0.

Thanks a bunch guy !
Charlot

Hi,
I found another place in my program where I was looping like crazy wainting for network data. Now the load is about 40%. Talk about bad coding habits from the single process world :).