Re: Optimizing View Drawing Code
Re: Optimizing View Drawing Code
- Subject: Re: Optimizing View Drawing Code
- From: Stephen Blinkhorn <email@hidden>
- Date: Fri, 8 Jan 2010 10:18:55 -0600
On 7 Jan 2010, at 18:16, Nick Zitzmann wrote:
On Jan 7, 2010, at 4:58 PM, Stephen Blinkhorn wrote:
The real cause seems to be all the view setup messaging that needs
to happen after I mark the view with setNeedsDisplay:YES. My top
hit in shark is: objc_msgSend (seems wrong for an app doing mostly
DSP :).
I should have mentioned earlier - regardless of top up or bottom down
Shark results - I'm pretty sure the cause of my high CPU is the behind
the scenes view setup prior to drawing that Cocoa does.
I can verify this by removing all drawing code from my drawRect:
method but gaining almost no extra performance (CGLayers are fast :).
Even with an empty drawRect: method if I comment out the
setNeedsDisplay:YES line in the meter then the CPU drops to almost
zero. I'm looking at 15-20% CPU on a dual core 2.3GHz machine - quite
a lot really.
Of course, GUI updates have a lower priority than all the audio stuff
but it would help to get the usage down.
Thanks,
Stephen
That's because you're probably looking at the bottom-up view, which
I think is still the default view in Shark, and it's not always
helpful in ObjC programs. Did you try looking at the top-down view?
Nick Zitzmann
<http://www.chronosnet.com/>
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