High CPU but no CPU processes running high??

Unanswered Question
Jul 29th, 2009

Hello,

I have a 7204 router running high CPU but not showing any high processes. I am not sure what is causing this and wondering if this is just a natural case of a hardware upgrade required:

BASR702#sh proc cpu | ex 0.00

CPU utilization for five seconds: 60%/59%; one minute: 50%; five minutes: 50%

PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process

37 189483500 576133389 328 0.16% 0.23% 0.24% 0 IP Input

87 75744528 174654752 433 0.08% 0.12% 0.14% 0 CEF process

BASR702#sh proc cpu | ex 0.00

CPU utilization for five seconds: 61%/60%; one minute: 50%; five minutes: 50%

PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process

14 121435408 306358976 396 0.16% 0.05% 0.06% 0 ARP Input

21 18609860 33444984 556 0.16% 0.06% 0.04% 0 Net Background

37 189483520 576133415 328 0.16% 0.22% 0.23% 0 IP Input

52 116230308 57019310 2038 0.16% 0.20% 0.22% 0 DHCPD Receive

105 4760 78888 60 0.08% 0.08% 0.15% 2 Virtual Exec

116 49556392 35707585 1387 0.08% 0.04% 0.01% 0 SNMP ENGINE

100

90 **

80 ** ***** *** ***

70 ** ********* *********

60 ** ********* *********

50 #* *##**###* *##**###*

40 ##* * **#########* * #########

30 ##* * ***#########* * ***#########*

20 ##* *** ** ***#########* * ***#########***** * ** *

10 ###***********#############************############*******************

0....5....1....1....2....2....3....3....4....4....5....5....6....6....7.

0 5 0 5 0 5 0 5 0 5 0 5 0

CPU% per hour (last 72 hours)

* = maximum CPU% # = average CPU%

System image file is "slot0:c7200-js-mz.122-5.bin"

cisco 7204 (NPE200) processor (revision B) with 114688K/16384K bytes of memory

Processor board ID 11061307

R5000 CPU at 200Mhz, Implementation 35, Rev 2.1, 512KB L2 Cache

4 slot midplane, Version 1.0

I don't believe this is causing any performance degradation to users but management of the device drops in and out frequently.

Can anyone advise whether it is wise to upgrade RAM, or if there is an uderlying problem causing high CPU?

rgds

Phil

I have this problem too.
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Joseph W. Doherty Wed, 07/29/2009 - 02:33

Assuming the cause of the CPU interrupt load is traffic load, your "management" issue might be either transient link congestion and/or transient CPU spikes. If your management traffic is using non-TCP, it could be sensitive to packet drops. If there are packet drops, QoS to guarantee sufficient bandwidth for your non-TCP management traffic might help.

If the CPU is spiking at 100%, I think changing the scheduler allocation might help insure software processes obtain sufficient CPU. (See "scheduler allocate" in http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a00800a70f2.shtml#initial_trblshooting)

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