On which thread are you allocating your graph?

Sent from my iPhone

> On Feb 19, 2015, at 1:26 PM, Dave O'Neill <[email protected]> wrote:
> 
> The actual refresh rate is unaffected at a verified 60FPS with a 
> CADisplayLink.  The little demo I made is drawing just two triangles with 
> 10-15% CPU. It is only the touch that is not being updated, when I animate 
> programmatically there is no lag at all even with unrelated touch tracking 
> happening simultaneously.  I think that somehow the MusicPlayer framework 
> causes the thread that tracks touch (which I had assumed was the main thread) 
> to wait on the audio render cycle.  What's interesting is that the main 
> thread doesn't get blocked, only the updating of touch events.  I know that 
> AUGraph (which is utilized by a MusicSequence by default) can block, but I 
> don't know if that's what's happening.  
> 
> Dave
> 
>> On Thu, Feb 19, 2015 at 1:04 PM, Steven Clark <[email protected]> 
>> wrote:
>> If you have limitless CPU cycles then it would be a weird interaction.  It 
>> sounds very very much like the sort of behavior you get if there aren’t 
>> enough CPU cycles for everything, and the system is optimized for something 
>> other than what you’re trying to do.
>> 
>>  
>> 
>> I had serious trouble with an iOS app that needed to track finger movement 
>> and display video at the same time.  It appears that iOS prioritizes 
>> tracking movement over anything else (at least, anything else that the app 
>> was doing).  The video got really choppy etc. whenever you’d move your 
>> finger, and clear up immediately when you move your finger away.  I found 
>> that the tracking loop was running as fast as it could, at the expense of 
>> all other computation.  (The system is optimized for visual user interaction 
>> responsiveness.)  I solved the problem by having my tracking routine do 
>> nothing and return immediately something like 4 times out of 5.  Response to 
>> finger movement was slightly affected negatively, but video was 
>> substantially improved.  I might have solved it by increasing the priority 
>> of the video processing thread, but that would have involved screwing around 
>> with Mach thread prioritization and hoping the app would still be approved 
>> by Apple for iTunes.
>> 
>>  
>> 
>> Steven J. Clark
>> 
>> VGo Communications
>> 
>>  
>> 
>> From: [email protected] 
>> [mailto:[email protected]] On 
>> Behalf Of Dave O'Neill
>> Sent: Thursday, February 19, 2015 3:21 PM
>> To: Ian Kemmish
>> Cc: [email protected]
>> Subject: Re: MusicPlayer with OpenGL interfere with UIGestureRecognizer
>> 
>>  
>> 
>> Really what I'm trying get to the bottom of, bug or no bug,  is how can 
>> these three seemingly unrelated api conflict? 
>> 
>> On Thursday, February 19, 2015, Ian Kemmish <[email protected]> wrote:
>> 
>> 
>> On 18 Feb 2015, at 17:00, "Dave O'Neill" <[email protected]> wrote:
>> 
>> > Once you see it being choppy press the play/stop button and see how
>> > the choppiness stops.  Weirdest bug ever.
>> 
>> Unless the gesture recognition software you're using is documented as making 
>> guarantees about latency, then it's not a bug.  It's life.
>> 
>> 
>> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>> Ian Kemmish                     18 Durham Close, Biggleswade, Beds SG18 8HZ
>> [email protected]        Tel: +44 1767 601361     Mob: +44 7952 854387
>> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
>> 
>> 
>> 
>> 
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