Trouble with Variations

[ColinP]

This is about some weird crashing in VM.

I've been trying to figure out how to do chord sequencing without a chord sequencer. The idea being to use VM's variations feature.

Here's what the patch looks like...

AS.png (695.16 KiB) Viewed 2707 times

Unfortunately I can't atttach the .voltagepreset file as it exceeds the 3 MB limit due to embedded samples and you'd need to have GS anyway.

All modules except the left-hand Chord Memory and the Chord modules in the lower cabinet have variations disabled and then I saved four different variations each with a different chord set up with the Chord Memory module (in monophonic mode - providing the root) and the Chord module. The LFO is then used to cycle through the variations and therefore the chords and also drives randomisation in the two Granular Synths. It's a bit fiddly but otherwise works a treat.

However while building and tweaking this patch it crashed VM multiple times. Making VM shutdown and disappear. Lookng at the log files there was nothing - they just stopped logging before the crash.

Now I've been building patches similar to this for ages and never seen a crash. The only novel feature is the use of variations. Although it could still be a bug in my modules of course!

What's weird is that it crashed lots of times (even after a reboot) but has now settled down for no apparent reason.

So my questions are:

Has anyone else seen similar behaviour with variations?

Has anyone had VM crashes like this that then seem to magically go away for no apparent reason?

Is there some special handling needed in the code to handle variations correctly?

How do you go about debugging something like this (as it's impossible to replicate the setup in VMD)?

Any advice welcome.

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Update:

After running OK for well over an hour it crashed again when my laptop went into screen saver mode.

[ColinP]

Anyone who is interested and has the Granular Synth bundle can download the patch here...

https://www.adroitsynthesis.com/andalus ... -appendix/

I'd be grateful for any feedback about whether it crashes on your machine or not.

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Edited to point to a new webpage.

[Steve W]

Just downloaded; been running 2 min. so far. I will leave it on while I do householdy tasks. I have experienced issues with Windows Audio even though I try to turn off as much "energy-saving" time-out parameters.

UPDATE 1: 25 min. no crash; will be listening/watching twitch steam live in about 10 min.; will try to leave VM running in the background.
UPDATE 2: 90 min. no crash; even had twitch on in two different browsers and switched VM from ASIO4ALL to Windows Audio [shared]; chatting, etc. Maybe its not crashing because I am actively using the computer. VM CPU at approx. 17-21%; Total CPU at approx. 5% over that.

[UrbanCyborg]

I've had problems with VM doing a crash-and-vanish under Windows. It seems more likely to occur if I leave both VM and VMD active, without using either for a while, or keep them in the background while using something else. Once such a crash occurs, it will recur with higher frequency, or VM will refuse to reload, until I reboot the system.

Reid

[Steve W]

I started to teach myself to use the designer (non-commercial) for about an hour or so a year or more ago. I probably haven't updated it but maybe when the there's a break in the stream I am watching I can try booting it to see if just running it triggers a crash with the patch.

UPDATE: I don't have any modules loaded, but after 2.8 hrs, the patch has not crashed (includes starting and running 2.3.4 and downloading / upgrading / booting 2.5.5 - Win 10 Pro 64 bit). FWIW, I hope this helps. And thanks for demo patch.

[Aarnville]

Colin, I think variations don't see a great deal of use amongst normal users and so changing variations using CV is likely to be an extremely minority activity. So I suspect you've hit on a bug of some sort. No idea how you debug it in VMD. You might need to ask the CA gnomes to look at it for you.

And as an aside, variations would be of much of more interest to me personally if they could change the wiring as well as the knob positions.

[ColinP]

Thanks guys, much appreciated.

The latest test I did was from a fresh boot with no involvement of VMD and it crashed after 56 minutes with nothing more than an occasional mouse wiggle.

[ColinP]

Hi Ian, our posts crossed.

Yeah, I think you're probaby right about variations being a relatively unexplored part of VM.

It all smells of some thread safety issue. I'm just reaching out to other devs and users for their experiences to see if there's anything I can fix at my end before I abandon the idea. I can't see CA doing anything.

Changing wiring is much more involved than the current implemetation which appears to be just based on calls to SetStateInformation() and Notify().

[Steve W]

I think "relatively unexplored" by new VM users is accurate. I have explored variations and even tested some personal ideas for live switching. I see much potential, this patch shows a wonderful use for them, and I hope you can figure out what's causing the crashes. To help, I will try to leave this patch running and just used my other (older) Win 10 PC to see if I can get this one to self-trigger power-saving mode.

UPDATE: I just spent 10 minutes aggressively playing the X-Y positions in both buffers including during chord [variation] changes. Wish I could trigger a crash for you, but purposeful, aggressive mouse movements haven't done it yet.

[ColinP]

Hi Steve,

Many thanks for the updates. Your machine seems to be doing a lot better than mine!

It's all a bit unexpected as VM is generally a pretty stable platform. So obviously I tend to think any problems must be my fault.

One reason that GS has a random trigger socket (apart from it being great for avant garde generative patches) is that it's enabled me to do rigorous stress testing. With GS Breakout connected then just about everything in GS can be randomized and I've run very long tests pulsing the random socket at high frequencies trying to find some weird configuration out of the zillions of modulation routings and settings that will cause a fault - but to no avail.

Then as soon as I start using variations things start crashing.