This is copy-pasted from Timo's comment in the "Todays Performance Data for 2.0.x" thread, but I didn't want to hijack that thread. In it, Timo says:
<snip> service imap { service_count = 0 }
(i.e. reuse imap processes) reduced the system CPU usage to almost nothing. But if you use different UIDs for different users you can't do that. </snip>
Is that safe to do in imap and/or pop3? Or at least no more insecure than using service_count=0 for imap-login and pop3-login? Since I saw that comment I've been googling around and grepping the wiki but I can only find instances of using it with "service imap-login", not "service imap" or "service pop3".
The mention in Timo's comment that it reduces the CPU usage by a lot got my attention, esp for pop3. We're already using service_count=0 for pop3-login and imap-login.