readahead slows down boot

[Alexander Heinlein]

Hi.

I tried to improve my boot time by using readahead. After booting with
"profile" readahead generated /etc/readahead/boot. But now my boot time
increased from 30s to 41s. readahead takes really long during "Reading files
needed to boot...".

bootchart output:
- without readahead:
  http://choerbaert.org/scy/pics/bootchart/2.6.24.4_normal.png
- with readahead:
  http://choerbaert.org/scy/pics/bootchart/2.6.24.4_readahead.png

Hardware:
1.86GHz CPU, 1024MB RAM, harddisk reaches about 42 MB/sec

What's the reason for this strange result?


Regards,
Alex