QEMU android aarch64 作为主机。 来宾 32 位 x86 或 x86_64 哪个会更快？

Question

Can i achieve more CPU performance by running x86_64 instead x86 on host which is aarch64?

Answer 1

Since the architecture of the host and guest mismatch, qemu will run the guest in emulation mode (tcg). This mode is very slow compared to native speed. If even there will a speed difference between 32 and 64-bit x86 guests, it should be very small.

Given that there are more cases for the 64-bit guests in disas_insn function in qemu source code (this function disassembles the original guest code and generates target architecture code), I would say that 32-bit guest should be a little bit faster. But this is not the only aspect that will influence performance and you have to compare both variants on your use cases to find the fastest.