[RP-PPPoE] High load + kernel mode

[Extra Fu]

Hello,

I'm using rp-pppoe v3.5 together with pppd v2.4.4 on  CentOS 5.3 on
relatively powerful machine (Dual Xeon 3GHz with 8 GB of RAM).

I have about 250 connected clients at any time, all of of them are WiMAX users.

The load average on the machine usually is between 50 and 80.
Virtually no I/O is being consumed as you can see from the following
mpstat ouput:

08:43:29 PM  CPU   %user   %nice    %sys %iowait    %irq   %soft
%steal   %idle    intr/s
08:43:30 PM  all    8.59    0.00   35.35    0.00    0.00    9.60
0.00   46.46   3010.00
08:43:31 PM  all    9.50    0.00   39.50    0.00    0.50   13.00
0.00   37.50   3641.00
08:43:32 PM  all   10.10    0.00   41.41    0.00    0.51   13.64
0.00   34.34   3790.82
08:43:33 PM  all    8.54    0.00   40.70    0.00    0.50   12.06
0.00   38.19   3370.30
08:43:34 PM  all    9.09    0.00   36.87    0.00    0.00   10.10
0.00   43.94   3302.02
08:43:35 PM  all    8.12    0.00   33.50    0.00    0.51   10.15
0.00   47.72   3171.43
08:43:36 PM  all    9.00    0.00   36.50    0.00    0.00   11.00
0.00   43.50   3172.00
08:43:37 PM  all   11.62    0.00   44.44    0.00    0.51   13.13
0.00   30.30   3934.34
08:43:38 PM  all   11.06    0.00   43.22    0.00    1.01   12.56
0.00   32.16   3775.00
08:43:39 PM  all    9.55    0.00   47.74    0.00    0.50   14.57
0.00   27.64   4117.82

What can I do to 'improve' the situation? Will moving to kernel-mode
pppoe 'reduce' the load on the server? Note that each pppoe process
consumes from 1.9 to 2.8% CPU right now - no other process consumes
that much.

Many thanks in advance for any insights,