/boot/loader.conf
加入
kern.hz=100
hint.apic.0.disabled=1
The default “tick” on FreeBSD is 1000 Hz, which is far greater than what a virtual machine can keep up with accurately, 100Hz is more reasonable value. APIC has been known to cause issues with FreeBSD, but is required if you are using SMP in your guest (2 or more processors).