[c-nsp] high cpu usage due to interrupts
ulisses
ulisses.alonso at rediris.es
Tue Feb 13 08:41:51 EST 2007
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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