I started aqua back up after they temporarily boosted the credit rate. This generated "Running (4.00 CPUs)" and then caused both of my collatz GPU tasks to slow down even though they were "Running (0.05 CPUs + 1.00 NVIDIA GPUs)" Time to completed went from minutes to hours. I then went and set the percent cpu from 100.0 down to 75.00 to make sure that the GPU's got a full CPU to feed them. This was a dual opteron 285 with two GTS-250.

This CPU pct change caused the existing aqua mt task to crash which is understandable. However, the next aqua task in the queue also started up "Running (4.00 CPUs)" . I expected to see 3 CPUs, not 4. Something is amiss.




The above seems to be a linux problem because my Vista-64 system (also dual opteron but 275 and one 9800GTX+) does not seem to have the same problem. It is running one gpu task and that multithreaded aqua task just fine and there was no need to change the CPU from 100pct to 75pct.



Note that the time for collatz to finish is still in the minutes, unlike the ubuntu 9.1 system where two collatz tasks are now taking hours.

The number of CPUs used by AQUA is set by the number of CPUs available at the time the task is allocated by the scheduler (there's a command line parameter in the workunit specification) - you'll probably find that the next AQUA task you download is set to 3 CPUs, and will remain that way even if you reset CPU usage to 100%

The number of CPUs used by AQUA is set by the number of CPUs available at the time the task is allocated by the scheduler (there's a command line parameter in the workunit specification) - you'll probably find that the next AQUA task you download is set to 3 CPUs, and will remain that way even if you reset CPU usage to 100%

You are correct. I just checked and the number of CPU's is down to 3 (after the 4.0 one finished). Also, the time to complete of the collatz is back to the normal minutes. Even when the CPU's were set to 4 the time for the collatz to complete was not as bad as I thought. The two tasks were counting down by minutes instead of seconds. They did end up tasking 1-2 hours to complete (instead of the normal 30 minutes) but they did not take the 4-5 hours that I was originally concerned about.