A single fullscreen window where the content view is either a Metal or GL layer, and nothing else in the layer hierarchy should be sufficient.
Using Instruments’s Metal and Display instruments you can see the drawables and the vsync they present on. Bring up the app switcher with cmd-tab to trigger the compositor and you can see the difference in Instruments.
One weird thing is, you can configure a 2 or 3 drawables swapchain on the Metal layer. Using 2 doesn’t work for me when the compositor bypass enables - it always locks to 30Hz, even when doing nothing but drawing a solid color. When the compositor is enabled, the 2 buffer swapchain runs at full speed, presumably because it’s effectively triple buffered. But, in the 3 buffer case, in fullscreen, you can see that you will just use 2 buffers provided you can render fast enough, so it seems like there’s no latency cost to the 3 drawable config in the ideal case.
Yah it was over a year ago so my memory is hazy but as far as I know I tried to do exactly that. I watched the WWDC talk and made sure I met all the conditions they say, and tried to use Instruments and Is It Snappy to verify it and I didn't seem to be triggering compositor bypass and had no way of figuring out why not. What I really want is a single open source demo app on Github where someone has said "I tested and this triggers Metal compositor bypass and I confirmed with Instruments and/or Is It Snappy"
Using Instruments’s Metal and Display instruments you can see the drawables and the vsync they present on. Bring up the app switcher with cmd-tab to trigger the compositor and you can see the difference in Instruments.
One weird thing is, you can configure a 2 or 3 drawables swapchain on the Metal layer. Using 2 doesn’t work for me when the compositor bypass enables - it always locks to 30Hz, even when doing nothing but drawing a solid color. When the compositor is enabled, the 2 buffer swapchain runs at full speed, presumably because it’s effectively triple buffered. But, in the 3 buffer case, in fullscreen, you can see that you will just use 2 buffers provided you can render fast enough, so it seems like there’s no latency cost to the 3 drawable config in the ideal case.