On Wed, Dec 30, 2015, at 10:33 AM, Michael McNeela wrote:
> The audio just glitched & dropped to silence a couple of days after the
> app
> was launched 'by hand' rather than via launchd, so I guess that rules out
> the thread priorities… *sigh* ;p

Well, you could still be in a priority inversion situation, where the
high-priority audio rendering thread is being starved by a
lower-priority thread that is failing to fill up a ring buffer with
samples. (For example, a decoder running on a background thread.)

How are you actually playing data? Are you generating sample data
yourself (even if it's something as simple as mixing)? What does your
threading model look like?

--Kyle Sluder

> 
> (The app runs the music in a bar/nightclub, hence why the Mac was running
> for a couple of days)
> 
> *Michael*
> 07595247282
> 
> On 26 Dec 2015, at 23:10, Michael McNeela <[email protected]> wrote:
> 
> OK, what about the audio realtime thread (during playback). It should be
> running at pri 97 -- is this true while the glitches are happening?
> 
> 
> It’s indeed at 97 for both type of launch, but …the glitches tend to take
> a
> few hours/days of running to present themselves (!), so I’ll just try
> ditching launchd for a few days & see if the random glitching disappears
> (that’s how that attached ’things I’ve tried' matrix came to be :p)
> 
> (Thanks for the push in the potentially-right direction by the way!)
> 
> *Michael*
> +447595247282
> 
> On 26 Dec 2015, at 22:52, Doug Wyatt <[email protected]> wrote:
> 
> OK, what about the audio realtime thread (during playback). It should be
> running at pri 97 -- is this true while the glitches are happening?
> 
> Doug
> 
> # sent from my iPhone
> 
> On Dec 26, 2015, at 14:40, Michael McNeela <[email protected]> wrote:
> 
> Hey Doug
> 
> Your matrix makes me wonder: are you trying to play from a launchd
> daemon?
> 
> 
> Yep; a launchd LaunchAgents daemon (i.e. not running as root)
> 
> Try taking an Instruments trace that captures thread scheduling activity.
> It sounds like the daemon is in a throttled state, which would show in a
> kernel or Instruments trace as having its threads running at a very low
> priority.
> 
> 
> A short ~5 second trace seems to show the *main thread* via launchd
> consistently at priority 31, vs the main thread via ‘double-click to
> open’
> at priority 46-47. (All other threads seem to have the same priorities
> regardless of how the app’s launched though)
> 
> *Michael*
> +447595247282
> 
> On 26 Dec 2015, at 18:34, Doug Wyatt <[email protected]> wrote:
> 
> Hi Michael,
> 
> Your matrix makes me wonder: are you trying to play from a launchd
> daemon?
> 
> Try taking an Instruments trace that captures thread scheduling activity.
> It sounds like the daemon is in a throttled state, which would show in a
> kernel or Instruments trace as having its threads running at a very low
> priority.
> 
> Doug
> 
> 
> 
> On Dec 26, 2015, at 10:11 , Michael McNeela <[email protected]> wrote:
> 
> Should you be curious, here’s what I’ve tried narrowing down so far;
> 
> <Screen Shot 2015-12-26 at 18.06.39 copy.jpeg>
> 
> *Michael*
> 07595247282
> 
> On 26 Dec 2015, at 16:55, Michael McNeela <[email protected]> wrote:
> 
> On 26 Dec 2015, at 16:48, Cyril Blanc <[email protected]>
> wrote:
> 
> Where are your video files ?
> 
> 
> On the internal SSD
> 
> What Mac do you use ?
> 
> 
> A late 2014 Mac mini (Macmini7,1), factory-configured to 2.6 GHz i5, 8GB
> RAM, 256GB SSD. The issue presents itself on three Macs of the same
> hardware configuration (bought & configured at roughly the same time),
> across 10.10.3, 10.10.5 and 10.11. I’m puzzled.
> 
> *Michael*
> 07595247282
> 
> On 26 Dec 2015, at 16:50, Michael McNeela <[email protected]> wrote:
> 
> Thanks for the input everybody. I should clarify that I’m simply playing
> regular ol’ video files using Cocoa’s AVPlayer; nothing spectacular, and
> the video playback continues unaffected as the audio stutters and drops.
> It’s incredibly odd.
> 
> Oh, and audio is being outputted through the Mac’s headphone port; not
> external audio interface via USB/FireWire, etc.
> 
> I’ve stopped SSH attempts bumping the CPU, just in case they were
> related,
> but the issue persists, so now I’m at a loss.
> 
> *Michael*
> 07595247282
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