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Re: Timer in drawing loop performance problems
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Re: Timer in drawing loop performance problems


  • Subject: Re: Timer in drawing loop performance problems
  • From: Jean-Daniel Dupas <email@hidden>
  • Date: Sat, 15 Aug 2009 10:14:31 +0200

And if you enabled vsync (which is by default), your code will never draw faster than the refresh rate (usually 60 Hz). That's probably why you never use more than 15 % of the CPU.

Le 15 août 2009 à 06:05, Roland King a écrit :

1) again I think you'll get better answers on the OpenGL list than the cocoa dev list - the guys on that list eat and breathe openGL and I've had some fantastic help there.

2) Are you targetting OSX 10.3 for your code? That tech tip says use an NSTimer only for 10.3 compatibility and CVDisplayLink for anything from 10.4 onwards. If you do have to use a timer have you read the caveat about enabling vertical synchronization (however one does that) or "the application will burn a lot of CPU time just firing off the timer, even though the drawing loop hasn't even completed its last run."?


On Aug 15, 2009, at 11:21 AM, Shayne Wissler wrote:

Hello,

Following the advice at
http://developer.apple.com/qa/qa2004/qa1385.html, I attempted using a
timer running at 1000Hz. However, on my iMac, this causes about a ~15%
CPU hit. When I run Shark, it says it's spending a good deal of time
in objc_msgSend, presumably in the call "[self setNeedsDisplay:YES]".


Is all this normal/expected?


Shayne Wissler _______________________________________________

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  • Follow-Ups:
    • Re: Timer in drawing loop performance problems
      • From: Shayne Wissler <email@hidden>
References: 
 >Timer in drawing loop performance problems (From: Shayne Wissler <email@hidden>)
 >Re: Timer in drawing loop performance problems (From: Roland King <email@hidden>)

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