Booting Faster

Explore strategies for accelerating system boot times in this 47-minute conference talk from linux.conf.au. Dive deep into the full stack of a computer's boot process, from firmware to operating system, to identify bottlenecks and optimize performance. Learn about efforts to reduce boot times on OpenPOWER systems, comparing single-socket desktops to multi-socket enterprise servers. Discover techniques for measuring and improving cold boot, warm boot, and reboot times. Examine the impact of various components like PCI, RAM, and display output on overall boot speed. Gain insights into the challenges of balancing boot time optimization with system functionality and user expectations. Analyze the effectiveness of different approaches, including distro tricks, hardware upgrades, and firmware optimizations. Understand the complexities of booting large-scale systems and the unique challenges they present. Consider the role of BMCs, graphics cards, and other hardware in the boot process. Leave with a comprehensive understanding of the factors influencing boot times and practical strategies for achieving significant improvements across various system configurations.

Intro
Premature optimization is the root of all evil
Booting is a feature
login
Before the OS: Petitboot
Step 1: Use tricks of the distros
Step 2: "Faster" hardware?
quiet kernel = many seconds of boot saved
[ 4.899386] Run /init as init process
2.5 seconds for unxz initramfs!
3 = 17
MB / 1.75MB/sec = 9.14 seconds
PCI?
What about BIG systems?
Hostboot does on-demand paging...
Thrashing before there's RAM!
We read firmware from Flash via a daemon on the BMC
SBE = "20 second black hole"
How long do other computers take?
VGA
Boot progress on discreet graphics card
Fast Reboot