dovecot - Nov 2010 - Todays Performance Data for 2.0.x

Dividing the imap processes's system CPU usage by number of imap
processes:

imap : 0.478872 of 975
imap : 0.460797 of 1242
imap : 0.409641 of 2482
imap : 0.424035 of 4711
imap : 0.488494 of 6148
imap : 0.56809 of 7031
imap : 0.734864 of 6965

So it's about 0.5 seconds of system CPU per imap login. I also get
something like 0.3 seconds of system CPU per imap login on my system.

Also setting:

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.

So, yeah, looks like the process initialization is wasting time
somewhere. I'll look further into it.

* Timo Sirainen <tss at iki.fi>:
> Dividing the imap processes's system CPU usage by number of imap
> processes:
> 
> imap : 0.478872 of 975
> imap : 0.460797 of 1242
> imap : 0.409641 of 2482
> imap : 0.424035 of 4711
> imap : 0.488494 of 6148
> imap : 0.56809 of 7031
> imap : 0.734864 of 6965
> 
> So it's about 0.5 seconds of system CPU per imap login. I also get
> something like 0.3 seconds of system CPU per imap login on my system.
OK
> Also setting:
> 
> 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.
Yes, unfortunately :(
> So, yeah, looks like the process initialization is wasting time
> somewhere. I'll look further into it.
Thanks a lot!

-- 
Ralf Hildebrandt
  Gesch?ftsbereich IT | Abteilung Netzwerk
  Charit? - Universit?tsmedizin Berlin
  Campus Benjamin Franklin
  Hindenburgdamm 30 | D-12203 Berlin
  Tel. +49 30 450 570 155 | Fax: +49 30 450 570 962
  ralf.hildebrandt at charite.de | http://www.charite.de