Performance-Mode: Low-Memory Warnings and Crashes in Multi-Bank Layout

Question

This template I’m working on for the nord drum 2 keeps crashing and flashing low memory warning (with no other apps open.)  the app in general is eating through battery on the verge of making it an unusable app, more than any other app I’ve used. I’m on an iPad Pro 9.7 screen with 128 gb, should be sufffeciient. It happens as I flip back and forth between banks using the switch to bank buttons labeled Drum Pads, X/Y, and Controls depending on the page.  I hope you can see something weird with this template though it’s no more complicated than any other template I’ve made. Thanks for the help!

Downloads: 468
2018-11-10-nord drum 2 master.mididesigner
Downloads: 468

Comments

Thanks Austin, while there are virtually no memory leaks in Performance Mode, we've got some issues we'll be working through soon for Design Mode. The main thing isn't anything about your layout itself, but rather how MD works in Design Mode. Relief is coming soon. The only workaround for right now is to crash the app yourself after getting out of design mode. Your changes will be saved and startup time should be quite minimal. It's a terrible solution but should get you moving as an emergency measure.

Thanks!

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That was wrong. See answer below, thanks.

Answer 1

Thanks, we've just replicated this performance-mode problem using your layout. We're taking a deep dive into this memory leak and we'll have a fix in either 2.98 or 2.99. On the one hand, it's a shocker to see. On the other, now that we can replicate, we can fix. Hang tight, thanks for your patience.

Comments

Well done Dan... I have chased down my share of Mem leaks in the past, its a bitch of a job.
Cheers
Thedood

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Thank you for looking into it. It was very strange as I’ve been using MD for years, made at least a dozen templates, usually more complicated than this one, and I’ve never had these kinds of issues.  I was just about to share the Drum 2 template with community, just putting on finishing touches, when it started acting up.
I’m just about to start a template for a strange looper/slicer/sampler pedal so I’m glad you found the issue. Let me know when you get a fix. Thank you!

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It’s not impossible that it’s a recent regression, that is to say a new bug. However, this might be an existing budget, and you just never triggered it because you never switched banks in this way. In any case, I can get the behavior to have been and I can see the memory moving up pretty quickly on our instruments, so it won’t be that easy to fix, but it won’t be impossible either. Thanks!
Dan

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@thedood anytime you want to talk battle stories from the dev corner, I’m in. Shoot me a mail. Glad to hear you’re doing Mono

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No worries Dan ;)
Just out of interest, there were a couple of times I noticed it slow down after maybe 10-20 minutes in design mode when doing that insanely large TR rack layout, but certainly not repeatedly.
Personally I was blown away by how well it did, considering that panel is 15meg (with only one added texture for the Korg logo), and I never once got an error re memory, I think it crashed once when deleting a page full of controls, but otherwise near perfect. I was on a 2017 iPad Pro, so an A10x? I believe with 12 inch screen/64gig. When it did go a little slow, I simply saved, exited the app, came back in and all was fine again.
I was using the stable 2.96? most of the time and I did open it a few times in Testflight to see how it was going but I didn't design a lot in that sorry, Ive started a new panel and now only design in Testflight.

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thedood, regarding design mode stuff: I still need to investigate further into that. I've started tracking down some retain cycles and found some good stuff. @austingreen: the plot thickens a bit. With your layout, if I force a memory warn (which I can do on the simulator), memory is quite stable around 100MB, which is okay. You would only know about the first memory warn, as a user, but they should be happening whenever there's a memory issue. I'm still digging in, but I'm not seeing the smoking gun I thought was there.

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Hi just checking in to see if there’s been any progress. I became spoiled using this template for my now neglected Nord Drum 2. I believe it will be useful to others as well. Thanks!

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Hey there, I need to look into this again. The last time I checked, the earlier enthusiasm was unwrarranted. While MIDI Designer will grow memory generously, on a memory warn it will jettison nicely. You’re getting a memory warn way before this slowdown (and memory growth) happens, right?

Also, and you might have answered this before, how do you know it’s “eating through memory?” (I’m not negating that)

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Thanks for getting back to me. I said or was trying to say it seems to run the battery down fairly quickly.  This is completely anecdotal, but with only mididesigner running on my iPad, it seems to use the battery faster than other apps. Thank you for looking into it when you get a chance.

What are the chances if I rebuilt this template from scratch that it would have the same problems? Keeping in mind I have no idea how these things work, could it be just this individual template/file is somehow corrupt, maybe something happened while editing as I was trying to figure out what I wanted vs some control/combination of controls or aspect of the template that will crash the app anytime it’s setup exactly like this?? ...I’m not saying this very well. Basically it’s not that hard to reproduce now that I know what I want but I’d rather not waste my time if chances are it will still crash. Thanks again!

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Hey there, thanks for the response. Yes, MIDI Designer is a responsible citizen when it comes to backgrounding. However, when it’s in the foreground, it’s not been particularly optimized for long battery life. This isn’t an impossible thing to optimize for, but we’re much more interested in memory use and speed.

It’s very unlikely that a rebuild from scratch will have different results, assuming you build the same thing. In fact, if you had a replicable problem — and that’s the first question, can you replicate it, or is it mostly intermittent, or can we probabilitically do a few steps and often get a crash — the goal would be to go the other way. By “the other way” I mean paring down: you delete huge parts of your layout to see if the problem goes away at some point.

I’ll have another play with this layout in the next couple of weeks and see what I can discover. Send us a reminder to support [at] mididesigner.com including a link to this QA issue if we drop the ball. We have much much better issue tracking for email tickets.

Thanks!
Dan

Answer 2

Thanks, we've just replicated this performance-mode problem using your layout. We're taking a deep dive into this memory leak and we'll have a fix in either 2.98 or 2.99. On the one hand, it's a shocker to see. On the other, now that we can replicate, we can fix. Hang tight, thanks for your patience.