[dovecot] Benchmarks

[Timo Sirainen]

Just tried Dovecot with 85k mails from Linux kernel mailing list, total
of 357MB. I mostly wanted to see if the new binary tree file works well.
And it does :) Nothing gets slowed down after deleting messages all
around the mailbox.

I tried several things with Dovecot, UW-IMAPd and Courier. You'll see
that Dovecot is faster in everything else except raw I/O which is a bit
strange, have to look why.

I think the most important thing anyway is the time spent opening
mailbox. Clients are doing "STATUS mailbox (UNSEEN)" very often and that
has to be fast. With Dovecot it's so small that I didn't even bother
adding it to the benchmarks, with UW-IMAPd it's 16 seconds, with courier
2 seconds.

Full results can be found at
http://dovecot.procontrol.fi/dovecot-benchmark.txt