[c-nsp] High CPU util on Cat4506

[Saku Ytti]

On (2006-11-20 15:56 +0000), Jee Kay wrote:

> I've got (very) high CPU util on one of my Cat4506s (SupIV running
> 12.2(20)EW1). I have a strong suspicion that it is being caused by the
> switch doing a bit of multicast forwarding (~20-30Mb/s).

How about SPAN for the control-plane traffic?

> I've gone through the Output Interpreter/Performance Tuning tips (ip
> mroute-cache was already enabled) but can't find anything that
> actually reduces the CPU usage.
> 
> The output of sh int switching/ sh int stats for the SVIs are:
> 
> #sh int vl410 stats
> Vlan410
>              Switch path    Pkts In   Chars In   Pkts Out  Chars Out
>                Processor          0          0          0          0
>              Route cache          0          0          0          0
>                 Hardware  106282027 22256087017   29334501 1394430880
>                    Total  106282027 22256087017   29334501 1394430880
> 
> #do sh int vl410 switching
> Vlan410
>           Throttle count          0
>         Drops         RP          0         SP          0
>   SPD Flushes       Fast          0        SSE          0
>   SPD Aggress       Fast          0
>  SPD Priority     Inputs          0      Drops          0
> 
>      Protocol       Path    Pkts In   Chars In   Pkts Out  Chars Out
>            IP    Process    1415199   88026932    1162606   72449768
>             Cache misses          0
>                     Fast          0          0          0          0
>                Auton/SSE          0          0          0          0
>           ARP    Process       2056     123360         27       1620
>             Cache misses          0
>                     Fast          0          0          0          0
>                Auton/SSE          0          0          0          0
> 
> 
> interface Vlan410
>  ip address 1.1.1.2 255.255.255.240
>  ip pim dr-priority 100
>  ip pim query-interval 5
>  ip pim sparse-mode
>  ip igmp query-max-response-time 3
>  ip igmp query-interval 10
>  standby 1 ip 1.1.1.1
>  standby 1 timers msec 300 1
> 
> 
> Does anyone have any ideas how to further diagnose this / what to
> enable to make the multicast packets go through a fast switching path?
> I've had considerably more than 20-30Mb/s of multicast through this
> class of switch before without running into any problem this extreme,
> but I can't seem to spot what is missing.
> 
> Thanks,
> Ras
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-- 
  ++ytti