High CPU util on UBR 7246vxr

Unanswered Question
Apr 16th, 2009

hi gurus,

im having high cpu util and causes high latency on my link.

#sh proc cpu | exclude 0.00% 0.00% 0.00%

CPU utilization for five seconds: 99%/93%; one minute: 99%; five minutes: 99%

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

5 6800908 333078 20418 0.48% 0.12% 0.11% 0 Check heaps

21 17951028 9407701 1908 0.40% 0.54% 0.54% 0 ARP Input

29 1451964 112474 12909 0.00% 0.03% 0.03% 0 Net Background

37 3521732 74073 47544 0.24% 0.09% 0.09% 0 CMTS CM MONITOR

55 3747700 1323536 2831 0.16% 0.12% 0.12% 0 CMTS MAC Protoco

56 23798432 4516995 5268 0.48% 0.45% 0.52% 0 CMTS MAC Timer P

57 3689896 48825391 75 0.24% 0.20% 0.23% 0 CMTS ds traffic

60 644168 731198 880 0.08% 0.01% 0.00% 0 CMTS Flap-list T

62 2929576 233565 12542 0.00% 0.04% 0.06% 0 CMTS MAC Parser

63 648572 297446 2180 0.08% 0.49% 0.48% 0 CMTS process

64 2756816 14329993 192 0.00% 0.06% 0.07% 0 CMTS IP glean

84 113956952 47511125 2398 3.24% 3.13% 2.70% 0 IP Input

105 970716 12771 76009 0.00% 0.01% 0.00% 0 Adj Manager

106 4512652 1033889 4364 0.24% 0.11% 0.11% 0 CEF process

110 8350836 1407897 5931 0.40% 0.25% 0.23% 0 DHCPD Receive

124 3392 292 11616 0.16% 0.01% 0.00% 3 Virtual Exec

156 652740 13080 49903 0.00% 0.01% 0.00% 0 Per-minute Jobs

159 366968 575050 638 0.00% 0.01% 0.00% 0 IP SNMP

161 7198440 293082 24561 0.00% 0.18% 0.19% 0 SNMP ENGINE

tia.

jeff

I have this problem too.
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mchin345 Wed, 04/22/2009 - 10:02

This list describes common symptoms of high CPU utilization.

1. High percentages in the show processes cpu command output

- If you have the output of a show processes cpu command from your Cisco device, you can use Output Interpreter to display potential issues and fixes.

2. Slow performance

3. Services on the router fail to respond.

For troubleshooting the High CPU utilization on Router click this link.

http://www.cisco.com/en/US/products/hw/routers/ps133/products_tech_note09186a00800a70f2.shtml

Joseph W. Doherty Wed, 04/22/2009 - 15:41

Your CPU utilization shows high interrupt which could just indicate too much traffic for your installed processor engine.

Take note of the information in Mary's reference for "High CPU Utilization due to Interrupts".

jeffersoncbriones Wed, 04/22/2009 - 17:13

Hi Mary/Joseph,

I already checked the switching part and the ip cef is already enabled. Does this mean that my UBR cannot accomodate more requests? Also i cannot see any number showing the 90% on my sh proc cpu, only numbers of 1.2%. Can i see the what PID really eating up the CPU.

Thanks.

Joseph W. Doherty Thu, 04/23/2009 - 03:05

You won't see interrupt CPU in the process list, since such CPU usage basically indicates packet processing/forwarding.

What "engine" is installed in your 7200 and what's the sum of all the interface traffic rates when the CPU is so busy?

PS:

You've insured CEF is active, have you also insured there no "no ip route-cache" configured anywhere, including on CMTS?

jeffersoncbriones Thu, 04/23/2009 - 17:33

Hi Joseph,

Cef is enabled globally, also i dont see any "no ip route-cache" on my config. Is this something to do with many clients connecting? I believe there are no NPE-G2 for ubr's.

cisco uBR7246VXR (UBR7200-NPE-G1) processor (revision A) with 983040K/65536K bytes of memory.

Thanks.

jeff

Joseph W. Doherty Thu, 04/23/2009 - 18:23

My guess would be there's too much traffic load, which many clients could cause. Would also, I suspect, depend on bandwidth caps per client.

There is a G2 uBR, see: http://www.cisco.com/en/US/prod/collateral/modules/ps4917/data_sheet_cisco_ubr7200_npe_g2_network_processing_engine.html

A G1 process is good for about 500 Mbps at 64 bytes sized packets. Keeping in mind you don't want to run the router flat out and need to allow for duplex traffic, you might only be looking at 100 to 300 Mbps practical bandwidth.

So, if you can sum up the bandwidth passing through the router, it could confirm whether the traffic load itself is the cause of the CPU load.

jeffersoncbriones Thu, 04/23/2009 - 18:32

Hi Joseph,

Basically im getting 3000 clients online on this machine with 400kbps bw. and my traffic is at max 170Mbps/50Mbps in/out. Thats why i want to test the G2 if it will lessen the load.

THanks.

jeff

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