Qemu Start Perf   

Before main()

shared library loading: ldd /usr/local/bin/qemu-system-x86_64 init() routines: QEMU is heavily object-oriented

Main()

VCPU create : Cache CPUID result , initialize in parallel Memory mapping : ACPI tables, Data for Virtual BIOS Virtual Machine/devices initalization: Introduce pc-lite(主板) and remove unused devices.

Virtual BIOS(delete–直接进到 kernel protected mode) https://github.com/bonzini/qboot

USE fw_cfg_dma instead of fw_cfg_io

Bootloader

Kernel realmode code

**Kernel protected mode code **

Userspace

Qemu start up 300ms –> 56ms