high system cpu usage, no culprit in top

[Justin Guerin <jguerin@cso.atmel.com>]

I am wondering if anyone has seen anything like this.  Here's a copy of top:

top - 09:28:43 up 1 day, 36 min,  1 user,  load average: 1.00, 1.06, 1.31
Tasks: 108 total,   1 running, 106 sleeping,   0 stopped,   1 zombie
Cpu(s): 32.1% us, 67.9% sy,  0.0% ni,  0.0% id,  0.0% wa,  0.0% hi,  0.0% si
Mem:    256760k total,   221872k used,    34888k free,    44084k buffers
Swap:   769568k total,    94744k used,   674824k free,    46452k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
  870 jguerin   15   0 33560  14m  29m S  0.7  5.6   3:34.61 kdeinit
  886 jguerin   15   0 27644  11m  23m S  0.3  4.5   4:01.37 kdeinit
  897 jguerin   15   0 32852  10m  21m S  0.3  4.3   0:12.54 kget
 2195 jguerin   17   0  2092 1024 1872 R  0.3  0.4   5:42.85 top
    1 root      16   0    72   52   52 S  0.0  0.0   0:01.55 init
    2 root      34  19     0    0    0 S  0.0  0.0   0:00.00 ksoftirqd/0
    3 root       5 -10     0    0    0 S  0.0  0.0   0:00.31 events/0
    4 root       5 -10     0    0    0 S  0.0  0.0   0:00.16 kblockd/0
    5 root       5 -10     0    0    0 S  0.0  0.0   0:00.00 pdflush
    6 root       5 -10     0    0    0 S  0.0  0.0   0:06.79 pdflush
    8 root      11 -10     0    0    0 S  0.0  0.0   0:00.00 aio/0
    7 root      15   0     0    0    0 S  0.0  0.0   0:02.04 kswapd0
   10 root      25   0     0    0    0 S  0.0  0.0   0:00.00 kseriod
  113 root       5 -10     0    0    0 S  0.0  0.0   0:00.00 reiserfs/0
  175 root      15   0     0    0    0 S  0.0  0.0   0:00.03 kapmd
  373 root      16   0  1744  624 1512 S  0.0  0.2   0:00.00 pump
  377 daemon    16   0  1748  608 1572 S  0.0  0.2   0:04.79 portmap

My CPU is 100% utilized, but no processes seem to be using the CPU.  I can't 
seem to figure out what's causing the load.  I know that something is, 
though, because xscreensaver is running very slow.

I've noticed that when I log out of my KDE desktop, the load goes away.  
When I log back in, it comes back, though not right away.  I can't figure 
out what process is causing the problem, though.

Note that, though X doesn't appear in this top output, it has be reniced to 
0 (from -10).  I'm running kernel 2.6.4 on Sid.  My last upgrade was only a 
couple of weeks ago, so I'm pretty up to date.

Google has, thus far, been unfruitful.

Any pointers greatly appreciated.

Thanks,
Justin Guerin