[nsp] High latency

[Kevin]

Yes I'm running BGP on the router with full routes, here's the output
from "sh proc cpu hist"
I am running CEF on the router also.

border1#show processes cpu history

     3344444888882222233333333332222222222333333333322222222222
     0011111777775555500000111119999977777000007777766666666664
100
 90         *****
 80         *****
 70         *****
 60         *****
 50         *****
 40    **********                              *****
 30  *********************************************************
 20  **********************************************************
 10  **********************************************************
    0....5....1....1....2....2....3....3....4....4....5....5....
              0    5    0    5    0    5    0    5    0    5

               CPU% per second (last 60 seconds)


     9999999998888777785999877899987789998899999887899889999878
     2232488961410343713091098769147741862036888736488233800094
100       ****           *     **      **   ****    **   *
 90  *********          ***   ****    ***  ******   **  ****
 80  *************   ** ***************************************
 70  ****************** ***************************************
 60  ****************** ***************************************
 50  **************#*****###****#*****#*####*****#*######******
 40  ****#******###############################################
 30  ##########################################################
 20  ##########################################################
 10  ##########################################################
    0....5....1....1....2....2....3....3....4....4....5....5....
              0    5    0    5    0    5    0    5    0    5

               CPU% per minute (last 60 minutes)
              * = maximum CPU%   # = average CPU%

It does look like bgp scanner is running at the inteveral,
How do I reduce the IP Input load?

Kevin,

-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Streiner, Justin
Sent: Wednesday, November 12, 2003 12:54 PM
To: cisco-nsp at puck.nether.net
Subject: Re: [nsp] High latency


On Wed, 12 Nov 2003, Kevin wrote:

> I'm having a really strange Issue with my 7513,
> It seems like the 7513 will make the latency on any link
> Jump up to a peak of 100ms to 400ms for a few packets then settle down

> to below 1ms Then after a little while (30sec to 1min) it'll do the 
> same thing, The cpu load when this happens is around 30%-40% (this 
> load is constant during the day),
> None of the interfaces are overloaded, it happens on all the
interfaces.
> Is there anything else I can do to diagnose the problem?
> It's a 7513 with an RSP4 and 12.2(14)s3.

Are you running BGP on this router?  If so, during these times of high
latency, does the "BGP Scanner" process tear up lots of CPU when you
look at a "sho proc cpu"?

If you do a "sho proc cpu hist", do you see lots of regular spikes up to
around 100%?

If so, I'll bet what you're seeing is the BGP Scanner process walking
the RIB.  If your router is heavily loaded and/or you're taking multiple
full feeds this process can eat up lots of CPU and produce the latency
you're seeing.

Running CEF won't specifically cure this problem, but it can help reduce
the amount of CPU your router spends on other tasks, particularly IP
Input.

jms
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