requesting advice for using Garbage Collection for a Cocoa MIDI app (so that I may use MacRuby)
Hi, I'd like to use MacRuby alongside Objective-C in a MIDI app I'm writing. I have already had success with evaluating MacRuby files from the AppDelegate and they work great in tandem with the rest of the code in Objective-C. I'm just concerned about getting further along with application, and all of a sudden finding out that there are MIDI timing issues that are being adversely affected by the garbage collection. Right now the MIDI output that the app is generating sounds tight, although the app is simple at this point, and I'm worried that as more objects get allocated, etc.. there may be some timing issues. If that does happen, will there be a way to fix that using NSThreads? Or would I need to use pthreads and register them with "objc_registerThreadWithCollector()" ? The reason I'm asking, is that I've tried to use an open-source MIDI framework that uses pthreads, and it will only work if GC is turned off. I've tried to call "objc_registerThreadWithCollector()" from that code, but it's still not working. At this point, I don't need to use the open source MIDI framework since I have MIDI working anyways.. but I'm concerned about timing issues creeping in later.. any advice is welcome... If someone says "Your crazy for trying to write a MIDI application using Garbage Collection", or "Don't worry, Garbage Collection won't be a problem"... that will help immensely.. or something in between if that's the case.. any more knowledge on this subject will be greatly appreciated.. Thanks ! Cheers, Tom Jordan
I have no expert weigh-in but only a quick google search revealed: From: http://www.cocoadev.com/index.pl?GarbageCollection
The big cost is to latency - the ability of a program to respond near-instantaneously to real-time situations. For many programs, this is not an issue - nanosecond latency is simply not needed. Other problem domains cannot use mark-and-sweep for this reason, for example music (eg MIDI) programs. Low latency is impossible because during the mark-and-sweep process, the program cannot respond to external stimulus, so latency cannot be lower than the length of a mark-and-sweep.
Maybe someone is kind enough to correct me. Regards, - Rob On 2011-07-27, at 7:54 PM, Tom Jordan wrote:
Hi,
I'd like to use MacRuby alongside Objective-C in a MIDI app I'm writing. I have already had success with evaluating MacRuby files from the AppDelegate and they work great in tandem with the rest of the code in Objective-C. I'm just concerned about getting further along with application, and all of a sudden finding out that there are MIDI timing issues that are being adversely affected by the garbage collection. Right now the MIDI output that the app is generating sounds tight, although the app is simple at this point, and I'm worried that as more objects get allocated, etc.. there may be some timing issues. If that does happen, will there be a way to fix that using NSThreads? Or would I need to use pthreads and register them with "objc_registerThreadWithCollector()" ? The reason I'm asking, is that I've tried to use an open-source MIDI framework that uses pthreads, and it will only work if GC is turned off. I've tried to call "objc_registerThreadWithCollector()" from that code, but it's still not working. At this point, I don't need to use the open source MIDI framework since I have MIDI working anyways.. but I'm concerned about timing issues creeping in later..
any advice is welcome... If someone says "Your crazy for trying to write a MIDI application using Garbage Collection", or "Don't worry, Garbage Collection won't be a problem"... that will help immensely.. or something in between if that's the case.. any more knowledge on this subject will be greatly appreciated.. Thanks !
Cheers,
Tom Jordan _______________________________________________ MacRuby-devel mailing list MacRuby-devel@lists.macosforge.org http://lists.macosforge.org/mailman/listinfo.cgi/macruby-devel
participants (2)
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Robert Lowe
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Tom Jordan