Announcement: Kernel with automatic boot tracing and prefetching available for testing (GSoC 2007)

Krzysztof Lichota krzysiek at
Sun Aug 12 18:28:40 UTC 2007

Hello everyone.
I am working this summer on "Automatic boot and application start file
prefetching" project as part of Google Summer of Code for Ubuntu.

I am glad to announce that first version of kernel with automatic boot
tracing and prefetching is available for widespread testing :)

How it works?
- During boot file accesses are recorded.
- During subsequent boots this trace is used to prefetch files before
they are used in order to speed up boot.

Everything is done automatically, without user intervention, and tracing
is possible to do at the same time as prefetching - as opposed to
currently used "readahead" package, which requires manual run of tracing
(and prefetching is not done during tracing).

Results from my latest tests, standard boot, average of 9 runs:
Prefetch kernel + prefetch  : 54.91s
Prefetch kernel + readahead : 58.76s
Ubuntu kernel + readahead   : 61.21s

Results of tests with OpenOffice run at boot, simulating disk-intensive
applications run at boot, average of 9 runs:
Prefetch kernel + prefetch  : 65.53s
Prefetch kernel + readahead : 74.43s
Ubuntu kernel + readahead   : 81.01s

Debs with kernel and supporting userspace utilities are available on
project page. Please see this webpage for instructions how to install them:

If you would like to do some automatic tests to accurately measure boot
time and effect of prefetching, please see this page:

Please report successes and possible problems to:
prefetch-users at (no registration necessary).

	Krzysztof Lichota

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