[c-nsp] RE: Unknown reason for High CPU 3620

Rodney Dunn rodunn at cisco.com
Wed Nov 3 12:14:42 EST 2004


btw, I missed the fact that you said it's all
bridging traffic.  Without testing it in the lab
I can't say if that's expected or not.  The bridging
code is not as good as the performance for normal packet
switching code.

Rodney

On Wed, Nov 03, 2004 at 11:08:14AM -0500, Rodney Dunn wrote:
> CPU load at interrupt level is almost always packet
> switching/features or alignment/spurious access corrections.
> 
> This CPU sounds high for that amount of traffic.
> 
> Can you list the full configuration /*taking out
> any confidential stuff*/ so we can see the features
> enabled?
> 
> 2nd, you really need to clean up that ethernet
> segement with all the collisions.  Can you convert
> it to full-duplex?  I don't recall if you can do it
> with the 3620 in later code.
> 
> Most likely it's not an issue with the ATM side.
> 
> Rodney
> 
> 
> On Wed, Nov 03, 2004 at 03:44:07PM -0000, Alex Foster wrote:
> > Thanks to the guys who responded - I have managed to narrow down the
> > cause to high interrupt utilization and not processor utilization - but
> > Im still a little unclear as to what is causing the high interrupt util.
> > - is the ATM interface causing this ?  Again the traffic load is little
> > over 1.5 meg (in/out) - but constant - so I am wondering if the
> > continual SARing is maybe having a negative effect on the CPU ?  If so -
> > is there a workaround or am I looking at a bigger platform to solve the
> > issue - if so any recommendations (I have a 3640 available but don't
> > know if this will provide much of an improvement).
> > 
> >  
> > 
> > Regards
> > 
> >  
> > 
> > Alex
> > 
> >  
> > 
> >  
> > 
> > -----Original Message-----
> > From: Alex Foster 
> > Sent: 03 November 2004 13:37
> > To: 'cisco-nsp at puck.nether.net'
> > Subject: Unknown reason for High CPU 3620
> > 
> >  
> > 
> > I have a 3620 that is currently maxing out its CPU for no apparent
> > reason - the traffic load on it at the moment is about 1 to 2 meg - and
> > sh proc cpu doesn't indicate any process that is causing the high CPU
> > util.  Most of the traffic is SIP but I wouldn't have thought this would
> > have any bearing.  There are only two interfaces on the box in use - an
> > ATM 155 and a 10bt.  The traffic from the 10bt is bridged to a PVC on
> > the ATM interface - nothing complicated.  
> > 
> >  
> > 
> > #sh proc cpu
> > 
> > CPU utilization for five seconds: 96%/93%; one minute: 90%; five
> > minutes: 91%
> > 
> >  PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process
> > 
> >    1      194708       9899756         19    0.00%  0.00%  0.00%   0
> > Load Meter
> > 
> >    2        2008          223                9004  1.41%  0.13%  0.03%
> > 66 Virtual Exec
> > 
> >  
> > 
> > #sh mem sum
> > 
> >                 Head    Total(b)     Used(b)     Free(b)   Lowest(b)
> > Largest(b)
> > 
> > Processor   61D70EA0    12120416     6616992     5503424     5303744
> > 5305428
> > 
> >       I/O    2900000     7340032     4387068     2952964     2920520
> > 2947260
> > 
> >  
> > 
> > #sh int e1/0
> > 
> > Ethernet1/0 is up, line protocol is up
> > 
> >   Hardware is AmdP2, address is 0005.3245.e070 (bia 0005.3245.e070)
> > 
> >   Description: 
> > 
> >   MTU 1500 bytes, BW 10000 Kbit, DLY 1000 usec,
> > 
> >      reliability 255/255, txload 34/255, rxload 37/255
> > 
> >   Encapsulation ARPA, loopback not set
> > 
> >   Keepalive set (10 sec)
> > 
> >   ARP type: ARPA, ARP Timeout 04:00:00
> > 
> >   Last input 00:00:00, output 00:00:00, output hang never
> > 
> >   Last clearing of "show interface" counters 1y4w
> > 
> >   Queueing strategy: fifo
> > 
> >   Output queue 0/40, 0 drops; input queue 0/75, 103522 drops
> > 
> >   5 minute input rate 1470000 bits/sec, 1984 packets/sec
> > 
> >   5 minute output rate 1355000 bits/sec, 2166 packets/sec
> > 
> >      2150894411 packets input, 1646909945 bytes, 0 no buffer
> > 
> >      Received 88151770 broadcasts, 0 runts, 0 giants, 0 throttles
> > 
> >      6397644 input errors, 42166 CRC, 32878 frame, 0 overrun, 6355422
> > ignored
> > 
> >      0 input packets with dribble condition detected
> > 
> >      2681876495 packets output, 1769855380 bytes, 0
> > underruns(556991/1663306/0)
> > 
> >      165 output errors, 2220297 collisions, 50 interface resets
> > 
> >      0 babbles, 47 late collision, 1067254 deferred
> > 
> >      118 lost carrier, 0 no carrier
> > 
> >      0 output buffer failures, 0 output buffers swapped out
> > 
> >  
> > 
> > #sh int atm 0/0.2
> > 
> > ATM0/0.2 is up, line protocol is up
> > 
> >   Hardware is RS8234 ATMOC3
> > 
> >   MTU 4470 bytes, BW 155000 Kbit, DLY 80 usec,
> > 
> >      reliability 255/255, txload 2/255, rxload 2/255
> > 
> >   Encapsulation ATM
> > 
> >   3075506957 packets input, 1094442885139 bytes
> > 
> >   2362546968 packets output,988686523562 bytes
> > 
> >   0 OAM cells input, 0 OAM cells output
> > 
> >   AAL5 CRC errors : 81
> > 
> >   AAL5 SAR Timeouts : 0
> > 
> >   AAL5 Oversized SDUs : 0
> > 
> >   AAL5 length violation : 26
> > 
> >   AAL5 CPI Error : 0
> > 
> >  
> > 
> > Thanks 
> > 
> >  
> > 
> > Alex
> > 
> > 
> > 
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