[c-nsp] RE: Unknown reason for High CPU 3620
Temkin, David
temkin at sig.com
Fri Nov 5 08:42:39 EST 2004
3620 can do 2,000pps process switched and 20,000-40,000 in CEF depending
on the alignment of the stars.
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net
> [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of
> Jack.W.Parks at alltel.com
> Sent: Friday, November 05, 2004 8:32 AM
> To: afoster at gammatelecom.com; rodunn at cisco.com
> Cc: cisco-nsp at puck.nether.net
> Subject: RE: [c-nsp] RE: Unknown reason for High CPU 3620
>
> To be honest, I think the box is maxed out from a PPS
> perspective. You are sending 2,000 pps each direction and I
> bet that all the packets are process switched. The 20-40
> kpps numbers are for CEF switching only. Obviously, Cisco
> would not sell many routers if they used non-CEF forwarding
> statistics in their documentation.
>
> You should be able to look at the "show interface switching"
> output to see if your process switching the packets. ATM SAR
> function should be handled by the ATM interface itself and
> NOT by the processor. The SAR function is not contributing to
> the CPU utilization. Since you are bridging, you are process
> switching and you are getting 2 kpps which is the maximum
> process switched performance you can expect.
>
> Check out this link. Scoll down to "Platform performance comparison"
>
> http://www.cisco.com/en/US/partner/products/hw/routers/ps5199/
> prod_bulletin09186a008032d40e.html
>
> I'm sure their are more stats about each platform, it just
> takes some digging around CCO.
>
> Jack
>
>
> -----Original Message-----
> From: cisco-nsp-bounces at puck.nether.net on behalf of
> Alex Foster
> Sent: Fri 11/5/2004 5:26 AM
> To: Rodney Dunn
> Cc: cisco-nsp at puck.nether.net
> Subject: RE: [c-nsp] RE: Unknown reason for High CPU 3620
>
>
>
>
> The Reasons for bridging are explained in the diagram below.
>
> Bridging Bridging
> Firewall ---- eth |7206| atm --------- atm |3620| eth ----- ISP
>
> So essentially I am using the ATM network to extend the
> connection from
> the ISP to our Firewall. In this situation you can see
> why I cant route.
> I cant see how L2TP will be of any help here - comments
> or suggestions
> are very welcome - Also the ATM network does not
> support MPLS (fairly
> old OS on our ATM switches).
>
> Thanks Again
>
> Alex
>
>
> -----Original Message-----
> From: Rodney Dunn [mailto:rodunn at cisco.com]
> Sent: 04 November 2004 15:42
> To: Alex Foster
> Cc: cisco-nsp at puck.nether.net
> Subject: Re: [c-nsp] RE: Unknown reason for High CPU 3620
>
> On Wed, Nov 03, 2004 at 11:46:09PM -0000, Alex Foster wrote:
> > Hi
> >
> > The LANE configuration is used for management only -
> occassional snmp
> > queries etc; so the bulk of traffic is being bridged
> between e1/0 and
> atm
> > 0/0.2. Are you saying therefore that bridging is far
> more intensive
> than
> > routing/switching at interrupt level? Why is that
> (sorry for the
> question -
> > just curious).
>
> Yes that's correct. Old code and was never designed
> for high speed
> switching.
>
> >
> > The load on this connection will soon increase to a
> constant 40 - 60
> Mbps
> > (again bridging - cant route unfortunately).
> Obviously the 3620 wont
> handle
> > this - I have a 7206 (NPE-400) available, would this
> box suffice for
> the
> > traffic load I am estimating - I can upgrade the 7206 to a G1
> processor if
> > needs be.
>
> It would have to be tested in the lab to know for sure.
> It's all
> about processor speed and feature excecution on a per
> packet basis.
> The old transparent bridging code isn't a great performer even
> though it's still under interrupt level. It's a
> totally different
> code path than raw packet switching.
>
> Someone else mentioned other types of L2 bridging (ATOM/L2TPv3).
> Those are new technologies designed to carry L2 frames over
> a L3 transport.
>
> It's hard to say what your best solution would be
> without understanding
> the overall environement you have. ie: Why are you
> bridging in the
> first place?
>
>
> >
> > Thanks for your time
> >
> > Alex
> >
> > -----Original Message-----
> > From: Rodney Dunn [mailto:rodunn at cisco.com]
> > Sent: 03 November 2004 17:40
> > To: Alex Foster
> > Cc: Rodney Dunn; cisco-nsp at puck.nether.net
> > Subject: Re: [c-nsp] RE: Unknown reason for High CPU 3620
> >
> >
> > Bridging with LANE at that rate. My guess is
> > that would probably be normal on a 3620.
> >
> > Your option would be to get a faster processor
> > or stop bridging.
> >
> > To be 100% sure it would need to be set up in the
> > lab with a packet generator under a controlled
> > test.
> >
> > Your sh int stat confirms at least the most of the
> > traffic is being handled under interrupt level which
> > is good.
> >
> >
> > Rodney
> >
> > On Wed, Nov 03, 2004 at 05:19:54PM -0000, Alex Foster wrote:
> > > Thanks Rodney - find config attached - the collisions were
> historical -
> > > the interface is running full-duplex - here is the
> current interface
> > > stats - the input errors are being investigated -
> but shouldn't be
> > > responsible for the high CPU. Have also included sh
> vers and sh int
> > > stat.
> > >
> > > #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 39/255, rxload 39/255
> > > 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 03:03:41
> > > Queueing strategy: fifo
> > > Output queue 0/40, 0 drops; input queue 1/75, 790 drops
> > > 5 minute input rate 1531000 bits/sec, 1935 packets/sec
> > > 5 minute output rate 1532000 bits/sec, 2170 packets/sec
> > > 21533985 packets input, 2108844947 bytes, 0 no buffer
> > > Received 62660 broadcasts, 0 runts, 0 giants,
> 0 throttles
> > > 130659 input errors, 1608 CRC, 1272 frame, 0
> overrun, 129051
> > > ignored
> > > 0 input packets with dribble condition detected
> > > 23817320 packets output, 2045363543 bytes, 0
> underruns(0/0/0)
> > > 0 output errors, 0 collisions, 0 interface resets
> > > 0 babbles, 0 late collision, 0 deferred
> > > 0 lost carrier, 0 no carrier
> > > 0 output buffer failures, 0 output buffers swapped out
> > >
> > > #sh vers
> > > Cisco Internetwork Operating System Software
> > > IOS (tm) 3600 Software (C3620-IS-M), Version
> 12.2(3), RELEASE
> SOFTWARE
> > > (fc1)
> > > Copyright (c) 1986-2001 by cisco Systems, Inc.
> > > Compiled Wed 18-Jul-01 13:45 by pwade
> > > Image text-base: 0x600089A8, data-base: 0x6116A000
> > >
> > > ROM: System Bootstrap, Version 11.1(20)AA2, EARLY
> DEPLOYMENT RELEASE
> > > SOFTWARE (fc1)
> > >
> > > xxxxxxxx uptime is 1 year, 29 weeks, 5 days, 1
> hour, 48 minutes
> > > System returned to ROM by power-on
> > > System image file is "flash:c3620-is-mz.122-3.bin"
> > >
> > > cisco 3620 (R4700) processor (revision 0x81) with
> 41984K/7168K bytes
> of
> > > memory.
> > > Processor board ID 25121827
> > > R4700 CPU at 80Mhz, Implementation 33, Rev 1.0
> > > Bridging software.
> > > X.25 software, Version 3.0.0.
> > > SuperLAT software (copyright 1990 by Meridian
> Technology Corp).
> > > 4 Ethernet/IEEE 802.3 interface(s)
> > > 1 ATM network interface(s)
> > > DRAM configuration is 32 bits wide with parity disabled.
> > > 29K bytes of non-volatile configuration memory.
> > > 16384K bytes of processor board System flash (Read/Write)
> > >
> > > Configuration register is 0x2102
> > >
> > >
> > > #sh int stat
> > > ATM0/0
> > > Switching path Pkts In Chars In
> Pkts Out Chars Out
> > > Processor 60671 5098714
> 161118 15856770
> > > Route cache 25347153 2543070267
> 22778769 2540265463
> > > Total 25407824 2548168981
> 22939887 2556122233
> > > Ethernet1/0
> > > Switching path Pkts In Chars In
> Pkts Out Chars Out
> > > Processor 43533 2674126
> 7176 430560
> > > Route cache 22903843 2234233191
> 25355781 2188907917
> > > Total 22947376 2236907317
> 25362957 2189338477
> > > Interface Ethernet1/1 is disabled
> > >
> > > Interface Ethernet1/2 is disabled
> > >
> > > Interface Ethernet1/3 is disabled
> > >
> > > Building configuration...
> > >
> > > Current configuration : 1868 bytes
> > > !
> > > version 12.2
> > > service timestamps debug uptime
> > > service timestamps log uptime
> > > service password-encryption
> > > !
> > > hostname xxxxxxxxxx
> > > !
> > > logging buffered 4096 debugging
> > > enable secret
> > > !
> > > ip subnet-zero
> > > !
> > > !
> > > no ip domain-lookup
> > > !
> > > call rsvp-sync
> > > !
> > > bridge crb
> > > !
> > > interface ATM0/0
> > > no ip address
> > > atm uni-version 3.1
> > > no atm ilmi-keepalive
> > > pvc 0/5 qsaal
> > > !
> > > pvc 0/16 ilmi
> > > !
> > > !
> > > interface ATM0/0.1 multipoint
> > > ip address xxxxxxx
> > > lane server-atm-address
> C5.777777777777777777777777.777777777777.77
> > > lane client ethernet xxxxxxx
> > > no cdp enable
> > > !
> > > interface ATM0/0.2 multipoint
> > > pvc 0/103
> > > encapsulation aal5snap
> > > !
> > > bridge-group 1
> > > !
> > > interface Ethernet1/0
> > > description
> > > no ip address
> > > no ip mroute-cache
> > > full-duplex
> > > no cdp enable
> > > bridge-group 1
> > > !
> > > no ip http server
> > > !
> > > no cdp run
> > > !
> > > bridge 1 protocol ieee
> > > !
> > > dial-peer cor custom
> > > !
> > > !
> > >
> > > -----Original Message-----
> > > From: Rodney Dunn [mailto:rodunn at cisco.com]
> > > Sent: 03 November 2004 16:08
> > > To: Alex Foster
> > > Cc: cisco-nsp at puck.nether.net
> > > Subject: Re: [c-nsp] RE: Unknown reason for High CPU 3620
> > >
> > > 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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