nDisplay induced stutter


I use nDisplay for driving simulator (CAVE-like setups), and our simulation has huge stutter (>300ms ticks) that I can’t explain. The only thing I know is that it’s related to nDisplay, because running the exe as standalone doesn’t show this behavior, neither does running it as master-only on nDisplay. But if any slave is connected, I get huge stuttering. Here’s a profiling done on the master, showing multiple 300ms ticks

Each spike is more or less the same, i.e. every thread is stalling or waiting for something, but I don’t know what. I have no idea what the GameThread “self” is, if it’s just another stall or if something is actually going on in there, and that would be my root issue. I run nDisplay with no swap sync policy.

Due to current Covid restriction, I can’t really get my hands on the hardware to run more tests, so any help would be very welcome.