Linux Kernel Fastboot on the Way

Explore Linux kernel fastboot optimization techniques in this 48-minute conference talk from the Linux Plumbers Conference. Discover how to reduce kernel boot time from 3000ms to 300ms through various optimizations, including enabling asynchronous device driver probing, implementing deferred memory initialization, optimizing rootfs mounting, and more. Learn about potential future optimization points, such as maximizing multi-core usage, reducing SMP initialization costs, and parallelizing device enumeration. Gain insights into profiling and analysis tools, and understand the importance of balancing universality and performance in kernel modules and configurations.

Intro
Kernel Fastboot
Agenda
Why we worked on boot optimization
Platform Brief Intro
Methodology - 3 Steps
How To Get Accurate Kernel Boot Time
Profile Tools
Analyze
How the Boot Time Is Consumed
Hotspots Overview
Boottime Hotspots
Too Few Drivers Use Asynchronous Probe
Original Boot
Boot With Asynchronous Probe
RootFS Mounting is a Critical Path
Highest CPU Frequency Booting
Kernel Modules and Config
Universality vs Performance
In-kernel Deferred Memory Init
Asynchronous Probe May Mess the Device Index
Efficient Firmware Init
Parallize SMP Initialization
systemd (user space)