[c-nsp] high cpu usage due to interrupts

[Rodney Dunn]

It's an RSP1 and the latest today is an RSP16.

What you need to look at is the pps being switched through
the box as well as the features you have enabled.

The CPU level there is probably normal for that processor.

If your VIPs have enough memory you could 'ip cef distributed'.


Rodney

On Tue, Feb 13, 2007 at 02:41:51PM +0100, ulisses wrote:
> 
> Hi all
> 
> I have followed the guidelines
> 
> http://www.cisco.com/en/US/products/hw/routers/ps359/products_tech_note09186a00801c2af0.shtml
> http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a00800a70f2.shtml#high_cpu
> 
> trying to find why I have a high cpu usage due to interrupts
> but I could not solve it, next I show diagnostics when only routing
> unicast traffic.
> 
> The basic configuration of the system (Cisco 7500) is:
> 
> IOS (tm) RSP Software (RSP-JSV-M), Version 12.1(14), RELEASE SOFTWARE (fc1)
> cisco RSP1 (R4600) processor with 65536K/2072K bytes of memory.
> R4600 CPU at 100Mhz, Implementation 32, Rev 2.0
> 2 AIP controllers (2 ATM).
> 2 VIP2 controllers (3 FastEthernet).
> 3 FastEthernet/IEEE 802.3 interface(s)
> 2 ATM network interface(s)
> 
> This is the load of the router:
> 
> EB-LasPalmas1#show interfaces | include is up|load
> ATM0/0 is up, line protocol is up
>      reliability 255/255, txload 55/255, rxload 152/255
> ATM0/0.1 is up, line protocol is up
>      reliability 255/255, txload 55/255, rxload 152/255
> FastEthernet1/0/0 is up, line protocol is up
>      reliability 255/255, txload 82/255, rxload 16/255
> FastEthernet2/0/0 is up, line protocol is up
>      reliability 255/255, txload 119/255, rxload 68/255
> FastEthernet3/0/0 is up, line protocol is up
>      reliability 255/255, txload 1/255, rxload 1/255
> FastEthernet3/1/0 is up, line protocol is up
>      reliability 255/255, txload 35/255, rxload 1/255
> 
> This is the load near the peak load of the router. I also haven't 
> seen any throttle in the interfaces. 
> 
> I think it is not too much, isn't it?
> 
> I have enabled all possible swithing options possible, see [1] at the end
> 
> I also have verified that there are no cache misses in the switching path
> and traffic uses the supossed switched path with show interfaces stats.
> 
> The cpu load is 100% (47 of 48%) caused by interrupts:
> 
> EB-LasPalmas1#show process cpu | include CPU|PID|Input
> CPU utilization for five seconds: 48%/47%; one minute: 45%; five minutes: 44%
>  PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process
>   13         176      1809         97  0.00%  0.00%  0.00%   0 ARP Input
>   40        7036    105293         66  0.00%  0.00%  0.00%   0 ATM OAM Input
>   44     6572080   1952147       3366  0.08%  0.09%  0.11%   0 IP Input
>   50           0         2          0  0.00%  0.00%  0.00%   0 SSCOP Input
>   56           0         2          0  0.00%  0.00%  0.00%   0 ILMI Input
>   64           0         2          0  0.00%  0.00%  0.00%   0 ATMSIG Input
>   69           0         1          0  0.00%  0.00%  0.00%   0 Probe Input
>   70           0         1          0  0.00%  0.00%  0.00%   0 RARP Input
>   78           0         2          0  0.00%  0.00%  0.00%   0 SPX Input
>   83         964       926       1041  0.00%  0.00%  0.00%   0 Tag Input
>   87           0         1          0  0.00%  0.00%  0.00%   0 Net Input
>  100        7536     39990        188  0.00%  0.00%  0.00%   0 CLNS Input
>  102       28504    109557        260  0.00%  0.02%  0.00%   0 IGMP Input
> 
> 
> Following the guideline on high cpu usage cause interrupts I found that:
> 
> Possible Causes of High CPU Utilization Due to Interrupts
>       Inappropriate Switching Path ---------- Not likely IMHO
>       CPU Performing Alignment Corrections -- No (verified)
>       Router Overloaded with Traffic -------- No (verified)
>       Software Bug -------------------------- I don't know (no access to Cisco TACS)
>       Voice Ports Configured on the Router -- No
>       Active Asynchronous Transfer Mode (ATM) Interfaces on the Router 
>       --------------------------------------- No (only the required ones)
>       Many Parallel Express Forwarding (PXF) Punts to the RP 
>       --------------------------------------  No
> 
> so I don't know what to check next... Any comment or suggestion?
> 
> Thanks so much in advance
> 
> 	Ulisses
> 
> 
> [1] 
> 
> EB-LasPalmas1#show ip interface | include is up|switch
> ATM0/0 is up, line protocol is up
> ATM0/0.1 is up, line protocol is up
>   IP fast switching is enabled
>   IP fast switching on the same interface is disabled
>   IP Flow switching is enabled
>   IP CEF switching is enabled
>   IP Flow switching turbo vector
>   IP Flow CEF switching turbo vector
>   IP multicast fast switching is enabled
>   IP multicast distributed fast switching is disabled
> FastEthernet1/0/0 is up, line protocol is up
>   IP fast switching is enabled
>   IP fast switching on the same interface is disabled
>   IP Flow switching is enabled
>   IP CEF switching is enabled
>   IP Distributed switching is enabled
>   IP Flow switching turbo vector
>   IP Flow CEF switching turbo vector
>   IP multicast fast switching is enabled
>   IP multicast distributed fast switching is enabled
> FastEthernet2/0/0 is up, line protocol is up
>   IP fast switching is enabled
>   IP fast switching on the same interface is disabled
>   IP Flow switching is enabled
>   IP CEF switching is enabled
>   IP Distributed switching is enabled
>   IP Flow switching turbo vector
>   IP Flow CEF switching turbo vector
>   IP multicast fast switching is enabled
>   IP multicast distributed fast switching is enabled
> FastEthernet3/0/0 is up, line protocol is up
>   IP fast switching is enabled
>   IP fast switching on the same interface is disabled
>   IP Flow switching is enabled
>   IP CEF switching is enabled
>   IP Distributed switching is enabled
>   IP Flow switching turbo vector
>   IP Flow CEF switching turbo vector
>   IP multicast fast switching is enabled
>   IP multicast distributed fast switching is enabled
> FastEthernet3/1/0 is up, line protocol is up
>   IP fast switching is enabled
>   IP fast switching on the same interface is disabled
>   IP Flow switching is enabled
>   IP CEF switching is enabled
>   IP Distributed switching is enabled
>   IP Flow switching turbo vector
>   IP Flow CEF switching turbo vector
>   IP multicast fast switching is enabled
>   IP multicast distributed fast switching is enabled
> 
> -- 
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