[Qemu-devel] branches are expensive

[Steffen Liebergeld]

Hi,

while measuring the execution of an ARM guest, I encountered that branches are
extremely expensive in terms of executed host instructions. A single ARM
branch takes 148 to 152 host instructions. In my setup host and guest use the
ARM instruction set architecture.

My question is what makes branches so expensive? What code is run when
executing a branch? Other instructions are translated to 14 to 40
instructions.

Any help is appreciated.

Greetings, Steffen