I'm trying to shave memory usage on a client's server.

top -S display:

11378 mysql      9   0  4968 4928  1980 S     0.0  0.4   0:00 mysqld
11380 mysql      9   0  4968 4928  1980 S     0.0  0.4   0:00 mysqld
11381 mysql      9   0  4968 4928  1980 S     0.0  0.4   0:00 mysqld
11382 mysql      9   0  4968 4928  1980 S     0.0  0.4   0:00 mysqld
11383 mysql      9   0  4968 4928  1980 S     0.0  0.4   0:00 mysqld
11419 mysql      9   0  4968 4928  1980 S     0.0  0.4   0:00 mysqld
11425 mysql      9   0  4968 4928  1980 S     0.0  0.4   0:00 mysqld
11526 mysql      9   0  4968 4928  1980 S     0.0  0.4   0:00 mysqld
11580 mysql      9   0  4968 4928  1980 S     0.0  0.4   0:00 mysqld
12279 mysql      9   0  4968 4928  1980 S     0.0  0.4   0:00 mysqld


mysql  Ver 11.18 Distrib 3.23.58, for pc-linux (i686)

If I let this run for days, then a couple of these processes will show 
:30 of activity, and the rest will show a perfect zero of cpu time.  So 
I thought it would be nice to reduce the number of threads running to 4. 

set-variable    = table_cache=4
set-variable    = thread_concurrency=2
set-variable    = max_delayed_threads=4
set-variable    = interactive_timeout=600
set-variable    = wait_timeout=600
set-variable    = flush_time=15
set-variable    = innodb_thread_concurrency=2
set-variable    = max_user_connections=2

The documentation specifically says thread_concurrency (on a Solaris) 
controls this.  I've tried other 'thread' variables, still no dice.

Suggestions?

--Alexander