site_archiver@lists.apple.com Delivered-To: darwin-kernel@lists.apple.com Hi There, On Sep 17, 2010, at 16:46 , dgatwood@apple.com wrote:

On Fri, September 17, 2010, David Wu wrote:

...

I'm a developer working on a multi-media application on Mac OS X. Our application is designed to run on all Mac PC/laptop including Mac Mini, iMac, MacBook, MacBook Pro, MacBook Air. Now we have a problem on testing our application on MacBook Air. When the application runs about 20-30 minutes, the idle CPU usage decreases to 0%. When I open the Active Monitor, I find the kernel_task consumes very high CPU usage, even higher than 100%. This causes the CPU resources for our application not enough to handle the multi-media tasks.

My observations (I have not looked for the source code) of this behavior on my 2nd generation MacBook Air 1.8 GHz, is that is how the Darwin kernel accounts for the thermal throttling of the CPU. It is directly related to how much activity is occurring and what the room temperature is. I have even seen it occur when the machine is almost idle and the ambient room temperature is like 36 deg C but mostly it occurs for me if the ambient room temperature is greater than about 22 deg C or I am using the MacBook Air directly on my lap or on a soft surface such as my bed. It is very annoying when in countries such as South Korea where air conditioning is set at 26 deg C... The joys of Intel CPU's, CraigN --- Craig Newell <craign@ieee.org> _______________________________________________ Do not post admin requests to the list. They will be ignored. Darwin-kernel mailing list (Darwin-kernel@lists.apple.com) Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/darwin-kernel/site_archiver%40lists.a... This email sent to site_archiver@lists.apple.com