[c-nsp] 3550 high cpu & process switched traffic

[Tassos Chatzithomaoglou]

I have a 3550 (12.1(22)EA8) which is constantly showing high cpu usage :

3550#sh proc cpu
CPU utilization for five seconds: 99%/96%; one minute: 97%; five minutes: 97%

If i'm not wrong, most of it is due to interrupts and i'm trying to find out what exactly is causing 
this. The 3550 has 3 SVIs (1 for management), 6 routed interfaces (5 of them have mls qos 
configured) and 2 L2 interfaces (one is trunk).

Also I would like to ask if the following output (only processor used for eggress traffic on ALL 
interfaces) is considered normal for 3550 switches:

3550#sh int stats
Vlan1
           Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                Processor        179      12172        179      10740
              Route cache          0          0          0          0
                    Total        179      12172        179      10740
Vlan4
           Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                Processor       2806     179584       2806     168360
              Route cache       8295     581139          0          0
                    Total      11101     760723       2806     168360
Vlan10
           Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                Processor   21993427 2785897656   20910415 2025707486
              Route cache 2289603255 1233480520          0          0
                    Total 2311596682 4019378176   20910415 2025707486
Interface FastEthernet0/1 is disabled

FastEthernet0/2
           Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                Processor          0          0     718962  112668280
              Route cache          0          0          0          0
                    Total          0          0     718962  112668280
FastEthernet0/3
           Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                Processor      98405    6710609     535543   50002650
              Route cache 2288708113 1141208459          0          0
                    Total 2288806518 1147919068     535543   50002650
FastEthernet0/4
           Switching path    Pkts In   Chars In   Pkts Out  Chars Out
                Processor      89343   11874108  396765671 2089412449
              Route cache  543340008 1149008067          0          0
                    Total  543429351 1160882175  396765671 2089412449

....


"sh int switching" shows the same problem for all interfaces : The Fast path has 0 entries for all 
protocols including IP.

Regards,
Tassos