I have to run a C program on terminal as fast as possible. However, there seems to be a cpu usage limit for the terminal, the program supose to run around 15 seconds on a linux machine with similar configuration where cpu usage is at 85-95%. But, it runs one minute on my macbook pro with cpu usage less than 15%. Finally, my question is, how do I utilize all of the 85% idle cpu for this program or at least most of the idle cpu?
MacBook Pro, Mac OS X (10.7.3)
Per se, MacOS X does not impose any CPU usage limits other than those from the processor scheduling priorities. Standard Unix scheduling priorities go from -20 to +20, with the default being 0. If you have administrator privileges, you increase your process' priority (a more negative value) with the nice or renice commands. See their man pages. On a four-core 15" or 17" MBP, even setting max -20 priority should not impact the rest of the system too much.
You may also want to go over and discuss these things in the Unix forums:
https://discussions.apple.com/community/mac_os/mac_os_x_technologies
There are no cpu usage limits on any user app that I have ever heard of. I don't recall what the priority setting is for applications at the moment but that only affect the execution priority. I suppose you could renice it but at what cost to the other processes I cannot say.
How to remove the cpu usage limit?
