Unable to utilize all CPU cores on Apple Silicon Macs

I am rendering some simple fractals, but it seems to take more time than it should. I find that the 4 Efficiency cores are running 100%, while the other 4 Performance cores are all idle. Interestingly, this doesn't happen when I am previewing the fractal. The rendering speed would be greatly increased if this can be fixed.
By the way, I am using a MacBook Air with an M1 chip.

Hi Mr. N. I’m getting something different on my M2 MacBook Pro.

All cores are in use while rendering:

Efficiency cores are not in use while previewing:

What's your time on the UF benchmark fractal?

I think this is due to the Rosetta 2 emulation layer. There is no software control over which cores are used, this is up to macOS to decide.

In the mean time, I'm making quite a lot of progress on the native Apple Silicon version of UF and that will certainly fix this.

To Mr B: Here is my benchmark and this is slow even compared to Intel Core i5-760 (a 2C4T CPU with a 10-year history). I consider this unacceptable.

To Mr. S: Thanks for explaining and I appreciate your effort. Wish you good luck in development.

For my M2 it was 2h20min. Thanks for testing. A lot of problem reports here turn out to be user error so it helps to get a confirmation.