I don't get the reasons behind Big + Little core designed, other than to appear to have a high thread count on paper.
This is 8 big cores + HT + 8 small cores, which is better, that or 16 big cores?
For mobile they might make a little bit of sense, those smaller cores would no doubt use less power than the big ones, and if you can turn the big ones off at idle you could probably cut the idle power consumption drastically, maybe from 5 Watts to 1 Watt and with that improve battery life, but you're losing a chunk of performance vs if they were all big cores.
That not really true. It's become very apparently from the Alder-lake threads that people don't quite understand how CPUs are designed or how they deployed in the design of the chip.
Part of the problem is terminology. They aren't 'little' cores, they are efficiency cores. That's particularly important because it more accurately describes what is actually going on in the design. Efficiency cores aren't just power efficient, the efficient in the entire PPA design process. So an efficiency core that is half the size and half the power of a performance core might still deliver 65% of it's performance for example.
So when you say is 16 big or 8+8 better that's not really fair. The 16 big core would be a much larger and costly piece of silicon to produce. How about we level the playing field to 3 hypothetical CPUs with similar die sizes and therefore could be sold for the same price. Do you still want 16 'big' cores?
CPU 1: 16 big cores = 100% single-thread performance, 100% Multi-thread performance @ 100% power
CPU 2: 8 big cores + 16 Efficiency cores = 100% single-thread performance, 120% multi-thread performance @ 90% power
CPU 3: 8 super big core + 8 Efficiency cores = 120% single-thread performance, 100% multi-thread performance @ 100% total power
The CPU designers have an area budget to work to. They just aren't going to give you twice as many big cores for the same product. The use of efficiency cores allows them to deliver higher total performance within the area budget, and can allow even more area to be spent on the remaining performance cores (and therefore the use of 'small' cores can lead to increased single thread performance). My only real concern is the software stack. Mobile phones have spent nearly a decade trying to perfect the CPU schedulers to overcome the complexities of this kind of setup. These days they do a pretty good job, but how good Windows will handle it is another question. I have no concerns about the hardware though, the design idea has been proven long ago and makes complete sense for what we know of CPU design today.