Could you please diagnose my bottleneck?

[whgang99]

Hello, I enjoy psp games on my phone with ppsspp. My phone is fast enough to play many games at playable level, but not fast enough to be frame-drops-free, so I play games with some degree of frame skipping. And recently, I got a question, exactly which part of my phone is being a bottleneck?
For example, on one scene, the game runs at 17fps out of 30 with frame skip disabled on my phone, regardless of internal resolution. And if I enable frame skips on that scene, game can run at full speed with frame rate dropping to a single digit, again, regardless of internal resolution. Does this mean the bottleneck is my CPU or GPU? Or you can't determine what's a bottle just by this? Also, my phone's processors are Qualcomm Snapdragon msm8974 2.3GHz quad-core and Adreno 330. (Which are known to be powerful, but unsuited for PPSSPP) (I have little experience in PC gaming, so I can't diagnose what these symptoms mean. I heard if game performance doesn't get better by lowering options, it's a CPU bottleneck but I don't know if it can be applied to emulators...)
I'd appreciate if you explain me what are the symptoms when CPU/GPU is bottlenecking an emulator. Thanks in advance.