[Dovecot] Dovecot Top?

Hello,

We occasional see high load peaks on our mail servers - these generally don't only last a few minutes. 'Top' show imap taking the lots of CPU resources, is there a dovecot 'top' like program to show dovecot which users are taking system resources?

Or how else can this kind of thing be tracked down?

(v1.1.7)

Thanks.

Andrew.