Dragonfly Hall high CPU usage

[Mattias Westlund]

I have been using Dragonfly Hall for a project the past week, and it has worked great. Up until today that is, when my CPU usage in REAPER suddenly skyrocketed. Looking at the performance meter, I noticed each instance of Dragonfly Hall had gone from using 1% CPU to around 11-12%. Bringing the effects offline and back online helped for a bit, but after a few minutes the issue returned.

Michael, or anyone else who might know, is there any potential cause for this behavior?

Windows 10 Pro x64, REAPER 4.78 x64, and the beta version of the Dragonfly verbs you posted a while back.

[Mattias Westlund]

Just installed v3 (didn't know it was out) and so far so good.

[Michael Willis]

(04-04-2020, 01:30 PM)Mattias Westlund Wrote: Just installed v3 (didn't know it was out) and so far so good.

Let me know if it happens again. I'm assuming that you are using multiple reverb busses? I still get the occasional bug report; from what I can tell they always seem to be related to running more than one instance of the plugin, but they happen so infrequently that it's really hard to reproduce and diagnose the problem.

[Mattias Westlund]

(04-04-2020, 02:02 PM)Michael Willis Wrote: Let me know if it happens again. I'm assuming that you are using multiple reverb busses?

Yep, three of them to be specific.

(04-04-2020, 02:02 PM)Michael Willis Wrote: I still get the occasional bug report; from what I can tell they always seem to be related to running more than one instance of the plugin, but they happen so infrequently that it's really hard to reproduce and diagnose the problem.

First time it happened here, it coincided with me loading up a trombone patch in TX16Wx. First I thought there was something wrong with the patch, but on closer inspection I noticed that the reverbs had gone haywire. After that, it started happening seemingly at random, so I can understand that it's hard to diagnose the problem. I'll post here if it happens again though!

[Mattias Westlund]

Still happens in v3 with no discernible pattern. Works fine for a long while, then it suddenly craps out.

[Michael Willis]

(04-06-2020, 11:13 PM)Mattias Westlund Wrote: Still happens in v3 with no discernible pattern. Works fine for a long while, then it suddenly craps out.

Aww, that's disappointing. It's tough being an open source developer. This project is at the point that it serves my own needs, but I also want it to be a robust tool for the community as well. It's just hard to diagnose problems that happen on a different operating system.

Incidentally, I had somebody recently approach me about integrating this into a commercial plugin host that he is developing. It would remain free of course; the reason I bring it up is that he's considering contributing some work that could possibly make it more stable on Windows. I don't know if or when a new release would happen, but it is a possibility.

I'm curious what your motivation is for using Dragonfly Reverb. Does it do something that you can't do with Valhalla, or are you challenging yourself to do a project entirely with free stuff?

[Mattias Westlund]

(04-07-2020, 02:17 AM)Michael Willis Wrote: I'm curious what your motivation is for using Dragonfly Reverb. Does it do something that you can't do with Valhalla, or are you challenging yourself to do a project entirely with free stuff?

Well, in this particular case (the Cheapskate Orchestra thing over in User Music) I'm trying to use as much freeware as possible. But I've also always loved the sound of Hibiki, though I rarely use it due to the ugly and convoluted interface. Dragonfly is much easier to use, not to mention easier on the eyes! I've never gotten around to actually using it for something before this, since I most often use my custom presets for the Valhalla verbs.

[Mattias Westlund]

Michael, I think I have a clue for you. In my case at least, the CPU spiking starts happening when an instance of Dragonfly Hall has been sitting idle with no audio passing through it for a while. It just happened here, and when I looked at the Performance Meter, the reverb instance that had audio (I was playing a strings patch) displayed normal CPU levels while the other two had shot up to ~13% each. Switching to instruments that use the other two buses, the CPU usage went back down to normal levels, but only temporarily. Usually I have to close and reopen the project for the reverbs to behave again.

Could this be some kind of denormals issue?

[Mattias Westlund]

Check out this capture, and watch the Front, Mid and Back buses in the Performance Meter (Reverb is just a folder track, containing the other three). A little while after playback stops, they shoot up.



To be clear, this is not a CPU throttling issue, as I have the High Performance power plan active here.

[Michael Willis]

(04-11-2020, 12:28 PM)Mattias Westlund Wrote: Michael, I think I have a clue for you. In my case at least, the CPU spiking starts happening when an instance of Dragonfly Hall has been sitting idle with no audio passing through it for a while.

Ooh, that's a good hint. I think I might know a way to fix that, let me see if I can carve out some time over the weekend to work on it.