Hi, I am currently doing some computation for climateprediction.net project, using spare cycles on my MacBook Air, which is running pretty much all day every day.

Trying to keep heat and power consumption at a minimum, I have configured 20% CPU usage, which is working quite well.

The only thing I don't like, is each task requires approx 160 hours of computation, of which I'm currently doing approx 4 hours per day. At this rate it will take 40 days per task.

For whatever reason, the client decides that a single 40 day task is not enough, and instead downloads and processes 4 of them in parallel.

I would prefer to keep it to a single task, or maybe two max, since the Mac Air only has 2 physical cores.

Any thoughts on how I can do this?

I have already configured it to use at most, 2 cores, and 20% CPU time.

Thanks.

Hi daedalus,

where did you specify the 2 core limit? Is it working? You should only see 2 tasks as running and the other 2 as waiting to run. If so than everything is working. If there are still 4 tasks running than maybe the core limit didn't kick in and you need to set it again on the host through BOINC Manager. With a recent version this should be enforced instantly.

You can also check the BOINC startup messages for the effective CPU restrictions.

Hi, for whatever reason setting the core limit to 2 didn't work.
I had to in addition set use at most 50% of cores, at which point it suspended two tasks and kept two running, which is what I want.

Perhaps it doesn't work as expected with mutlithreading, and restricting to two (physical?) cores will still spawn four logical threads. I don't know how the app is coded.

Anyway with the combination of settings (2 cores + use at most 50% avail cores) it seems to be working now. Thanks.