[mythtv] Choppy performance on Mac Intel builds / scaling issue?

[James Mitchell]

On Sun, Mar 26, 2006 at 09:41:03PM +0200, usleepless at gmail.com wrote:
> Hello James,
> 
> pardon my curiosity: do you know where the "ml_set_interrupts_enabled"
> are coming from?

Since the ml_set_interrupts_enabled are, by percentage, a much smaller
number of the total cycles for scenarios where the system seems unable
to keep up (1080i, 480i scaled), versus the 480i non-scaled, where they
are the largest contributor, I'm assuming that they are related to some
sort of normal blocking activity in other threads (usleeps, for example,
heh). 

Here's the Shark breakdown of the ml_set_interrupts_enabled call tree
for a 1080i trial run:

3.8%	3.8%	mach_kernel	ml_set_interrupts_enabled	
0.0%	2.8%	mach_kernel	  thread_block_reason	
0.0%	2.8%	mach_kernel	    thread_block	
0.0%	1.6%	mach_kernel           mach_wait_until_trap	
0.0%	0.9%	mach_kernel           uiomove	
0.0%	0.3%    mach_kernel           semaphore_wait_internal	
0.0%	0.5%    mach_kernel       thread_invoke	
0.0%    0.1%    mach_kernel       clock_get_calendar_microtime	

James