[jitter] [boring] optimizing with shark output

On Aug 23, 2007, at 5:13 PM, pnyboer wrote:

>
> I'm looking at the shark output from running a video patch, and it  
> looks like most of the cpu usage (37%, according to shark) is a  
> result of ml_set_interrupts_enabled from the mach_kernel library.

This is the operating system blocking on some thread waiting for  
something to happen. This could be resultant from any number of  
things and might not even be limiting performance. If on a dual core  
machine could be something like the audio thread or something just  
waiting to run, on another processor which has open cycles to keep  
letting the thread spin (harmless). It might be parallel processing  
threads waiting for the threads on the other processor to finish,  
spinning with the available extra CPU cycles to spare (harmless). It  
might be jit.window waiting for the monitor to sync (test with  
jit.window @sync 0). It might also be the result of using too much  
VRAM or RAM in general and waiting for the operating system to page  
Virtual VRAM or RAM (try quitting other apps and closing extra  
windows lying around in the background). Or any number of other  
possibilities.

If you don't get big differences from things like the last two  
suggestions, I'd actually focus your optimization on other areas,  
especially if you're on a multi-processor machine.

-Joshua