[squid-users] High CPU load with diskd ?

I've upgraded from squid-2.5.STABLE4 to squid-2.5.STABLE5 on a
Tru64Unix 5.1 alpha XP1000.

First I've started 2.5.ST5 Monday at noon using ufs.
Then I've restarted 2.5.ST5 Tuesday at noon using diskd.

Just see at:
http://www.univ-st-etienne.fr/criter/stats/mrtg/cpu.janon.html

CPU load is, say, twice the load of squid before using diskd.
Also, nightly CPU load is really higher than squid-2.5.ST4

It seems squid is using CPU, not diskd:
janon/root> ps aux
USER PID %CPU %MEM VSZ RSS TTY S STARTED TIME COMMAND
squid 3931 77.2 34.5 181M 176M ?? R Mar 09 10:20:10 (squid)
root 0 17.3 5.3 643M 27M ?? R < Mar 08 08:55:50 [kernel
idle]
squid 3953 1.5 0.1 2.63M 480K ?? U Mar 09 18:45.20 diskd 40
25344 4025345 4025346

From cachemgr.cgi:
        CPU Usage, 5 minute avg: 77.92%
        CPU Usage, 60 minute avg: 76.15%

I thought diskd would help our squid cache under heavy load
(2,000+ clients, more than 60 requests/second, very long answers)

Any idea ?
Thanks in advance.

-- 
_________________________________________________________________
Magali BERNARD - CRITeR - Université Jean Monnet de Saint-Etienne
23 rue du Dr Paul Michelon - 42023 St-Etienne Cedex 2 - FRANCE
Tel: 04.77.48.50.62