Poor CPU utilization Android

[[Unknown]]

Quote:I still have 1 gigahertz to spare but PPSSPP doesn't use it.

This surprises many people, but there are two reasons:

1. Your phone OS decides whether PPSSPP uses slow or fast cores. It is trying to balance heat production and battery drain with performance. Any app that uses significant CPU for an extended period of time may be relegated to slow cores.

The reality is that some apps manage their CPU usage poorly, but still run fine on slower devices. At the end of the day, people buy phones more when they get better battery life. What other choice did your phone manufacturer have? If they didn't prevent apps from sucking your battery dry, no one would buy their phones.

2. As much as everyone is convinced (from emulation of other systems) that CPU is where performance stops and ends for PSP emulation, typically most people are limited more by GPU performance than CPU performance.

This is why PPSSPP is not using all your CPU power. It doesn't need it, and using that extra power wouldn't help. It needs the GPU.

We do have code to use the CPU only and not use your GPU at all. It's incredibly slow. On phones, contributors to PPSSPP have often joked that you need to measure its speed in "seconds per frame" because frames per second would be so low.

So instead, we use your GPU pretty heavily. But honestly, a lot of phones have terrible GPUs (way better than using the CPU even so.) Worse, a lot of phones with decent GPUs have terrible OS drivers that make poor use of the GPU. This means sometimes the GPU isn't even maxed out either, even though we're sending it work constantly.

That's also why frameskip and graphical settings often have the most impact on emulation speed. They directly control the amount of work your GPU is doing. Those settings barely affect the CPU at all.

-[Unknown]