5.6 linux Performance

I’m seeing a performance drop after upgrading to Unreal Engine 5.6. I’m running two instances in the same VM. To isolate the issue, I created an empty project with the basic map and tested it on Linux using Pixel Streaming.

When I run one instance, the frame time is about 15 ms. But when I run two instances, the frame time jumps to around 50 ms.

Even with a completely empty level, I get about 7 ms for a single instance, and 30 ms when running two.

In Unreal Engine 5.5, the frame time scaled linearly, but in 5.6 it does not.

Also, taskset -c doesn’t help in this case.

Is this a bug in Unreal Engine 5.6?