[c-nsp] interrupt cpu // processor routed packets

bill fumerola billf at mu.org
Wed Jun 4 16:26:55 EDT 2008


folks,

at $WORK we use 7301s as border routers at our sites. recently,
we've seen an uptick in cpu. it's too difficult to isolate the change
that was made, but it's our belief that some feature or option has caused
a majority of packets to be run through the processor as opposed to
through cef/caches. this is happening on several routers, but i'll limit
the output to one of them.

rtr1.ash#sh int stats 
GigabitEthernet0/0
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor 2784467772 2512553561 3619252418   92352609
             Route cache 1983176953 3753638533 1446323093 1223073183
                   Total  472677429 1971224798  770608215 1315425792
Tunnel1004
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor 3025559230 3288625164    3990521  311834632
             Route cache  238098300 2332344373 2454903224 3851240155
                   Total 3263657530 1326002241 2458893745 4163074787

there are more tunnels than tu1004. some of them are key'd, but most are
not. 

rtr1.ash# sh int | i key|checksum
  Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled
  Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled
  Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled
  Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled
  Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled
  Tunnel protocol/transport GRE/IP, key 0x138B, sequencing disabled
  Tunnel protocol/transport GRE/IP, key 0x138D, sequencing disabled
rtr1.ash#

gi0/0 has a few .1q subints.  one is the local machines, three more are
transit providers. the unicast/multicast filter tables are not full.

i'm most familiar with the cat6k series and i'm unable to find what
is causing the processor path to be tripped. we use GRE tunnels
fairly heavily in our setup and it's possible that is what is causing
such a surge.


the counters wrap from time to time.

rtr1.ash#sh proc cpu | e 0.0 
CPU utilization for five seconds: 52%/46%; one minute: 53%; five minutes: 57%
 PID Runtime(ms)   Invoked      uSecs   5Sec   1Min   5Min TTY Process 
   5    35199292  87282048        403  0.47%  0.32%  0.52%   0 Pool Manager     
  46   5504888562337240730        235  4.79%  2.40%  3.62%   0 IP Input         
rtr1.ash#

all the cpu seems to be in interrupt context.

what i'm looking for from the list is a plethora of commands to investigate
what forwarding path is causing this. i've reached the end of my knowledge
on this platform.

plenty more output after my .sig

-- bill fumerola 






interface Tunnel1004
 description ASH <-> PAO
 bandwidth 1048576
 ip address
 ip mtu 1500
 ip pim sparse-dense-mode
 keepalive 5 3
 ipv6 enable
 ipv6 ospf 36692 area 0
 tunnel source 
 tunnel destination 
 no clns route-cache
!

interface GigabitEthernet0/0
 description trunk to sw1.ash
 no ip address
 no ip proxy-arp
 duplex full
 speed 1000
 media-type rj45
 no negotiation auto
 no clns route-cache
!
interface GigabitEthernet0/0.1
 description ash management subnet
 encapsulation dot1Q 1 native
 ip address secondary
 ip address secondary
 ip address 
 ip access-group PRODUCTION out
 no ip proxy-arp
 ntp broadcast
 ntp multicast ttl 1
 ipv6 address XXX::/64 eui-64
 ipv6 enable
 ipv6 nd prefix XXX::/64
 ipv6 ospf network broadcast
 ipv6 ospf 36692 area yyy.yy.yy.y
!    


these two commands were fired one right after another:
rtr1.ash#sh ip cef switching  st

Path   Reason                          Drop       Punt  Punt2Host
RP RIB Packet destined for us             0 2740402100          0
RP RIB Total                              0 2740402100          0

RP LES Packet destined for us             0 2852377644          0
RP LES Encapsulation resource             0    7056820          0
RP LES Total                              0 2859434464          0

RP PAS Packet destined for us           130 2852377644          0
RP PAS No adjacency                47098437          0    7291703
RP PAS Incomplete adjacency            9582          0         57
RP PAS TTL expired                        0          0   28060459
RP PAS IP options set                     0          0        502
RP PAS Bad IP packet length              50          0          0
RP PAS Routed to Null0            505265584          0    2740520
RP PAS Features                      623282          0     519123
RP PAS IP redirects                       0          0     112010
RP PAS Total                      552997065 2852377644   38724374

All    Total                      552997065 4157246912   38724374
rtr1.ash#sh ip cef switching  st

Path   Reason                          Drop       Punt  Punt2Host
RP RIB Packet destined for us             0 2740402151          0
RP RIB Total                              0 2740402151          0

RP LES Packet destined for us             0 2852377695          0
RP LES Encapsulation resource             0    7056820          0
RP LES Total                              0 2859434515          0

RP PAS Packet destined for us           130 2852377695          0
RP PAS No adjacency                47098437          0    7291703
RP PAS Incomplete adjacency            9582          0         57
RP PAS TTL expired                        0          0   28060460
RP PAS IP options set                     0          0        502
RP PAS Bad IP packet length              50          0          0
RP PAS Routed to Null0            505265584          0    2740520
RP PAS Features                      623282          0     519123
RP PAS IP redirects                       0          0     112010
RP PAS Total                      552997065 2852377695   38724375

All    Total                      552997065 4157247065   38724375


rtr1.ash#sh int gi0/0 | i flush
  Input queue: 0/75/110893/113688459 (size/max/drops/flushes); Total output drops: 7
rtr1.ash#sh int gi0/0 | i flush
  Input queue: 24/75/110893/113688459 (size/max/drops/flushes); Total output drops: 7
rtr1.ash#sh int gi0/0 | i flush
  Input queue: 0/75/110893/113688459 (size/max/drops/flushes); Total output drops: 7
rtr1.ash#sh int gi0/0 | i flush
  Input queue: 0/75/110893/113688464 (size/max/drops/flushes); Total output drops: 7
rtr1.ash#


rtr1.ash#sh int tun1004
Tunnel1004 is up, line protocol is up 
  Hardware is Tunnel
  Description: ASH <-> PAO
  Internet address is 
  MTU 1514 bytes, BW 1048576 Kbit, DLY 500000 usec, 
     reliability 255/255, txload 1/255, rxload 1/255
  Encapsulation TUNNEL, loopback not set
  Keepalive set (5 sec), retries 3
  Tunnel source  destination  fastswitch TTL 255
  Tunnel protocol/transport GRE/IP, key disabled, sequencing disabled
  Tunnel TTL 255
  Checksumming of packets disabled, fast tunneling enabled
  Last input 00:00:00, output 00:00:00, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 6
  Queueing strategy: fifo
  Output queue: 0/0 (size/max)
  5 minute input rate 5898000 bits/sec, 562 packets/sec
  5 minute output rate 371000 bits/sec, 429 packets/sec
     3263777089 packets input, 1485561186 bytes, 0 no buffer
     Received 0 broadcasts (216 IP multicast)
     0 runts, 0 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored, 0 abort
     2458985720 packets output, 4172988844 bytes, 0 underruns
     0 output errors, 0 collisions, 0 interface resets
     0 output buffer failures, 0 output buffers swapped out
rtr1.ash#

rtr1.ash#sh int gi0/0
GigabitEthernet0/0 is up, line protocol is up 
  Hardware is BCM1250 Internal MAC, address is 0019.0723.7c1b (bia 0019.0723.7c1b)
  Description: trunk to sw1.ash
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec, 
     reliability 255/255, txload 36/255, rxload 36/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is RJ45
  output flow-control is unsupported, input flow-control is off
  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 never
  Input queue: 0/75/110893/113689811 (size/max/drops/flushes); Total output drops: 7
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 144971000 bits/sec, 105268 packets/sec
  5 minute output rate 144617000 bits/sec, 104815 packets/sec
     506548581 packets input, 3492190905 bytes, 0 no buffer
     Received 0 broadcasts (60 IP multicast)
     0 runts, 0 giants, 10485 throttles
     0 input errors, 0 CRC, 0 frame, 2851 overrun, 0 ignored
     0 watchdog, 62466151 multicast, 0 pause input
     804535373 packets output, 2855171008 bytes, 0 underruns
     5 output errors, 0 collisions, 4 interface resets
     0 babbles, 0 late collision, 0 deferred
     5 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out

GigabitEthernet0/1 is up, line protocol is up (connected)
  Hardware is Gigabit Ethernet, address is 0017.0ec5.fa81 (bia 0017.0ec5.fa81)
  Description: trunk to rtr1.ash
  MTU 1500 bytes, BW 1000000 Kbit, DLY 10 usec, 
     reliability 255/255, txload 36/255, rxload 36/255
  Encapsulation ARPA, loopback not set
  Keepalive set (10 sec)
  Full-duplex, 1000Mb/s, media type is 10/100/1000BaseTX
  input flow-control is off, output flow-control is unsupported 
  ARP type: ARPA, ARP Timeout 04:00:00
  Last input never, output 00:00:01, output hang never
  Last clearing of "show interface" counters never
  Input queue: 0/75/0/0 (size/max/drops/flushes); Total output drops: 0
  Queueing strategy: fifo
  Output queue: 0/40 (size/max)
  5 minute input rate 143627000 bits/sec, 99179 packets/sec
  5 minute output rate 143913000 bits/sec, 101524 packets/sec
     1941640569 packets input, 1959608239 bytes, 0 no buffer
     Received 14836035 broadcasts (0 multicast)
     0 runts, 34 giants, 0 throttles
     0 input errors, 0 CRC, 0 frame, 0 overrun, 0 ignored
     0 watchdog, 176806 multicast, 0 pause input
     0 input packets with dribble condition detected
     3253282407 packets output, 3316970055 bytes, 0 underruns
     0 output errors, 0 collisions, 1 interface resets
     0 babbles, 0 late collision, 0 deferred
     0 lost carrier, 0 no carrier, 0 PAUSE output
     0 output buffer failures, 0 output buffers swapped out


rtr1.ash#sh proc cpu his
                                                               
     4444455555999993333344444555554444444444555557777777777666
     1111144444999997777711111000005555500000222222222233333000
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)

     1    11       1        1     1     1   11      11      1  
     0988900998888909997888909989909978809880088889900889889098
     0019400967468707207337308681709178806850030523300526262065
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%

     1111111             1 111  1111               1111111 1         11    
     0000000999999999999909000980000999999999999999000000090999999999009999
     0000000856798789999909000690000699273458869978000000070936721939004555
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%



------------------ show memory statistics ------------------


                Head    Total(b)     Used(b)     Free(b)   Lowest(b)  Largest(b)
Processor   62AE8E20   961638740   316495312   645143428   418466788   407990612
      I/O    C000000    67108864     3819536    63289328    62389760    59792568

------------------ show process memory ------------------


Total: 1028747604, Used: 320310832, Free: 708436772


rtr1.ash#sh int stats                    
GigabitEthernet0/0
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor 2785237678 3111284079 3619643339  664678802
             Route cache 2067631367  666969097 1530781222 2423385488
                   Total  557901749 3778253176  855457265 3088063680
GigabitEthernet0/1
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
GigabitEthernet0/2
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0          0          0
             Route cache          0          0          0          0
                   Total          0          0          0          0
Loopback0
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor          0          0     142535    8368344
             Route cache          0          0          0          0
                   Total          0          0     142535    8368344
Tunnel4
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor  373469861 3046343742    3690003  272784327
             Route cache   23275816 3725601538  283927218 2806689241
                   Total  396745677 2476977984  287617221 3079473568
Tunnel504
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor   17385911 1678075426    3563859  259189688
             Route cache   27712845 3025461654    8661024 1259982335
                   Total   45098756  408569784   12224883 1519172023
Tunnel1004
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor 3025892770 3796521547    3991045  311877040
             Route cache  238161330 2343707136 2455214989 3885274948
                   Total 3264054100 1845261387 2459206034 4197151988
Tunnel3800
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor    8211288 2542852750    1525188  114050100
             Route cache   62716883 1069521078   74749790 2675399475
                   Total   70928171 3612373828   76274978 2789449575
Tunnel3801
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor     714577   74801208    1026386   79775264
             Route cache   20998778 1692442218   21744435 2287929534
                   Total   21713355 1767243426   22770821 2367704798
Tunnel5003
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor     247537   32510851     226170   21713449
             Route cache      15310   10756016       9053    1380467
                   Total     262847   43266867     235223   23093916
Tunnel5005
             Switch path    Pkts In   Chars In   Pkts Out  Chars Out
               Processor     243659   25989478     235628   22812424
             Route cache        156    7800422      16057    2281736
                   Total     243815   33789900     251685   25094160
rtr1.ash#


rtr1.ash#sh int counter protocol status 
Protocols allocated:
 GigabitEthernet0/0: Other, IP, Spanning Tree, ARP, IPv6
 GigabitEthernet0/1: Other, IP
 GigabitEthernet0/2: Other, IP
 Loopback0: Other, IP, IPv6
 Tunnel4: Other, IP, IPv6
 Tunnel504: Other, IP, IPv6
 Tunnel1004: Other, IP, IPv6
 Tunnel3800: Other, IP, IPv6
 Tunnel3801: Other, IP, IPv6
 Tunnel5003: Other, IP, IPv6
 Tunnel5005: Other, IP, IPv6

Allocation failures: 0

rtr1.ash#sh int ac
GigabitEthernet0/0 trunk to sw1.ash
                Protocol    Pkts In   Chars In   Pkts Out  Chars Out
                   Other     264692   15117496   17050137 1055304738
                      IP  556483091 2335985659  836666136 2558588475
           Spanning Tree         75       4620          0          0
                     ARP    7026907  421614516    7421368  474967552
                    IPv6       8121     697465      99936   13515042
GigabitEthernet0/1 ibx-ash 
                Protocol    Pkts In   Chars In   Pkts Out  Chars Out
                   Other          0          0     901882   54112920
GigabitEthernet0/2 
                Protocol    Pkts In   Chars In   Pkts Out  Chars Out
                   Other          0          0     901882   54112920
Loopback0 
                Protocol    Pkts In   Chars In   Pkts Out  Chars Out
                      IP     113422    4688938     113422    4688938
                    IPv6      29117    3679692      29117    3679692
Tunnel4 Palo Alto <-> Ashburn 
                Protocol    Pkts In   Chars In   Pkts Out  Chars Out
                      IP  396425141 2068923018  286064777 2937637278
                    IPv6     274798   23175878     264441   22365270
Tunnel504 Seattle <-> Ashburn
                Protocol    Pkts In   Chars In   Pkts Out  Chars Out
                      IP   44806526 4261836688   10672780 1380352723
                    IPv6     274648   23042300     264085   22375392
Tunnel1004 ASH <-> PAO 
                Protocol    Pkts In   Chars In   Pkts Out  Chars Out
                      IP 3263784881 2246072058 2457710040 4052359156
                    IPv6     256929   21734754     247604   21041124
Tunnel3800 NYC/ASH
                Protocol    Pkts In   Chars In   Pkts Out  Chars Out
                      IP   70628512 3388325615   75423944 2715519036
                    IPv6     292602   24427300     282672   23686330
Tunnel3801 LON/ASH
                Protocol    Pkts In   Chars In   Pkts Out  Chars Out
                      IP   21423029 1717785221   22174960 2313419422
                    IPv6     262199   22088760     252611   21415144
Tunnel5003 NYC/ASH 
                Protocol    Pkts In   Chars In   Pkts Out  Chars Out
                      IP     165838   26258520     157278   10153234
                    IPv6      90007    7530632      77966    6609290
Tunnel5005 NYC/ASH
                Protocol    Pkts In   Chars In   Pkts Out  Chars Out
                      IP     146196   16743133     164296   11055686
                    IPv6      90627    7681266      87411    7442894
rtr1.ash# 

rtr1.ash#sh ip bgp sum
BGP router identifier 208.69.32.1, local AS number 36692
BGP table version is 12344783, main routing table version 12344783
254794 network entries using 28791722 bytes of memory
1261161 path entries using 65580372 bytes of memory
17 multipath network entries and 56 multipath paths
261519/45635 BGP path/bestpath attribute entries using 28244052 bytes of memory
154267 BGP AS-PATH entries using 4121068 bytes of memory
66 BGP community entries using 1632 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 126738846 total bytes of memory
Dampening enabled. 320 history paths, 596 dampened paths
503501 received paths for inbound soft reconfiguration
BGP activity 502024/247223 prefixes, 10834511/9573341 paths, scan interval 60 secs



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