threads problem with 9.3.2

[Aleksandr Ivanov]

I have server with 2xXeon CPU's.

$ uname -a
Linux dns1-2 2.6.15-1-686-smp #2 SMP Thu Feb 23 05:47:57 CET 2006 i686 GNU/Linux

"cat /proc/cpuinfo" show me 4 processors

BIND 9.3.2 compiled with --enable-threads --prefix=/usr --enable-ipv6 --sysconfdir=/etc/bind

When I run BIND, I see in log:
Feb 27 10:54:37 dns1-2 named[20041]: starting BIND 9.3.2 -u bind -c /named/etc/named.conf
Feb 27 10:54:37 dns1-2 named[20041]: found 4 CPUs, using 4 worker threads
Feb 27 10:54:37 dns1-2 named[20041]: loading configuration from '/named/etc/named.conf'
Feb 27 10:54:37 dns1-2 named[20041]: listening on IPv6 interfaces, port 53
Feb 27 10:54:37 dns1-2 named[20041]: listening on IPv4 interface lo, 127.0.0.1#53
Feb 27 10:54:37 dns1-2 named[20041]: listening on IPv4 interface eth0, xxx.xxx.xxx.xxx#53
Feb 27 10:54:37 dns1-2 named[20041]: listening on IPv4 interface eth1, xxx.xxx.xxx.xxx#53

BUT with "ps -aux" I see ONLY 1 thread:
bind     20041 23.5  4.7 102184 49600 ?      Ssl  10:54   2:48 /usr/sbin/named -u bind -c /named/etc/named.conf

How can I use multithreaded BIND?

-- 
Aleksandr