Windows 7 - Boot Performance

Yesterday Engineering Windows 7, the official blog of Windows 7 was updated with a new post by Michael Fortin who is one of Microsoft’s Distinguished Engineers. In this post he told about the tasks needed to be performed efficiently and with a high degree of parallelism by a PC to boot fast, and how they will implement it in Windows 7.

"For Windows 7, we have a dedicated team focused on startup performance, but in reality the effort extends across the entire Windows division and beyond. Our many hardware and software partners are working closely with us and can rightly be considered an extension to the team.

Startup can be one of three experiences; boot, resume from sleep, or resume from hibernate. Although resume from sleep is the default, and often 2 to 5 seconds based on common hardware and standard software loads, this post is primarily about boot as that experience has been commented on frequently. For Windows 7, a top goal is to significantly increase the number of systems that experience very good boot times. In the lab, a very good system is one that boots in under 15 seconds.

For a PC to boot fast a number of tasks need to be performed efficiently and with a high degree of parallelism.

Files must be read into memory.
System services need to be initialized.
Devices need to be identified and started.
The user’s credentials need to be authenticated for login.
The desktop needs to be constructed and displayed.
Startup applications need to be launched.

Because systems and configurations differ, boot times can vary significantly. This is verified by many lab results, but can also be seen in independent analysis, such as that conducted by Ed Bott. Sample data from Ed’s population of systems found that only 35% of boots took less than 30 seconds to give control to the user. Though Ed’s data is from a small population, his data is nicely in line with what we’re observing. Windows Vista SP1 data (below) also indicates that roughly 35% of systems boot in 30 seconds or less, 75% of systems boot in 50 seconds or less. The Vista SP1 data is real world telemetry data. It comes to us from the very large number of systems (millions) where users have chosen to send anonymous data to Microsoft via the Customer Experience Improvement Program."

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