FreeBSD Can Now Boot in 25 Milliseconds
The sorting algorithm replacement in the FreeBSD kernel has improve loading speed by a factor of 100 or more… and even though it’s aimed at micro-VMs, the gains should benefit everyone. From a report: MicroVMs have been a hot area of technology research and development for the past half decade or so. The basic idea is a reinvention of some concepts and technologies that IBM invented together with the hypervisor in the 1960s: designing operating systems specifically to run as guests under another operating system. This means building the operating system specifically to run in a virtual machine and to communicate with resources provided by a specific hypervisor instead of fake hardware.
This means that the guest operating system needs almost no support for real hardware, only VirtIO drivers that communicate directly with the facilities provided by the host hypervisor. In turn, the hypervisor should not provide an emulated PCI bus, emulated power management, emulated graphics card, emulated network interface cards, etc. The result is that the hypervisor itself can be much smaller and simpler. The result of ruthlessly shrinking both the hypervisor and the operating system that runs inside it is that both ends can be much smaller and simpler. This means that virtual machines can use much less resources and start much faster.