LinuxConf.Au: Why does my machine take so long to boot?
Every new machine seems to take longer to boot than the one it replaced. This is annoying for kernel developers who have to reboot frequently and are thus less productive. It also annoys users who like to turn their machines off while they're not using them. In environments with 99.999% guaranteed uptimes, going from a 100 second boot time to a 160 second boot time makes the difference between three crashes permitted a year and two crashes a year.
Some of the time-consuming things are dictated by hardware specifications. For example, each SCSI device can take up to 15 seconds to probe (but more typically around 20-30 seconds per bus). However, there is no reason that we have to wait for scanning one thing to finish before scanning the next one.
This presentation will discuss various techniques being used to improve boot time. I will cover the advantages and disadvantage of parallel pci driver initialisation. I will also cover the asynchronous scsi scanning code. Other possibilities for improving bootup time will also be presented, including memory management initialisation and ACPI.