[f-nsp] High CPU MLX-4

Iain Robertson iain.robertson at gmail.com
Wed Apr 19 02:40:22 EDT 2017


Are all unused interfaces in the disabled state?

I've seen a circumstance where, with some optics, an enabled interface with
no remote device connected to it results in high LP CPU on the affected
line cards.  Workaround in that case was to ensure that all
disused/disconnected interfaces are disabled.



On 19 April 2017 at 14:40, Joe Lao <Joelao8392 at mail.com> wrote:

> Boot     : Version 5.6.0T165 Copyright
>
> (config)#sh conf | inc icmp
> no ip icmp redirects
>
> on both
>
>
>
> *Sent:* Wednesday, April 19, 2017 at 8:57 AM
> *From:* "Eldon Koyle" <ekoyle+puck.nether.net at gmail.com>
> *To:* "Joe Lao" <Joelao8392 at mail.com>
> *Cc:* foundry-nsp <foundry-nsp at puck.nether.net>
> *Subject:* Re: [f-nsp] High CPU MLX-4
> Have you disabled icmp redirects?  That is a common cause of unexplained
> high cpu utilization.  I think the command is: no ip redirect (either
> interface or global).
>
> Also, which code version are you running?
>
> --
> Eldon
>
> On Apr 18, 2017 7:14 PM, "Joe Lao" <Joelao8392 at mail.com> wrote:
>>
>> Hello List
>>
>> My colleague posted on this list last month about a LP CPU issue
>> experienced on MLX routers with GRE tunnels
>>
>> The issue did not resolve itself instead we asked our customers to not
>> send outbound traffic through us
>>
>> However a new issue has arised
>>
>>
>> Our topography is as follows
>>
>> CARRIER A -----> MLX-4-1 ---- MLX-4-2 ----> CARRIER B .. Carrier B
>> connection is specifically designed to tank attacks, carrier A backhauls
>> clean/protected traffic
>>
>> MLX-4-2 holds our GRE tunnels
>>
>>
>> Now we are seeing 95% LP CPU on MLX-4-1 and a packet capture shows only
>> GRE packets from MLX-4-2 destined for the customers GRE endpoint
>>
>>
>> SLOT  #:               LP CPU UTILIZATION in  %:
>>              in 1 second:  in 5 seconds:  in 60 seconds: in 300 seconds:
>>      1:        94            94             94              94
>>
>>
>> LP-1#show tasks
>>   Task Name       Pri  State  PC        Stack       Size  CPU Usage(%)
>> task vid
>>   --------------  ---  -----  --------  --------  ------  ------------
>> --------
>>   con              27  wait   0005c710  040c5dc8   32768             0  0
>>   mon              31  wait   0005c710  041b7f10    8192             0  0
>>   flash            20  wait   0005c710  041c6f40    8192             0  0
>>   dbg              30  wait   0005c710  041beec0   16384             0  0
>>   main              3  wait   0005c710  23cc6f40  262144             1
>> 101
>>   LP-I2C            3  wait   0005c710  27d70ee0    4096             0
>> 101
>>   LP-Assist         3  wait   0005c710  29bbef00   32768             0
>> 101
>>   LP-FCopy          3  wait   0005c710  29bc3f00   16384             0
>> 101
>>   LP-VPLS-Offld     3  wait   0005c710  29bc8f00   16384             0
>> 101
>>   LP-OF-Offld       3  wait   0005c710  29bcdf00   16384             0
>> 101
>>   LP-TM-Offld       3  wait   0005c710  29bd2f00   16384             0
>> 101
>>   LP-Stats          3  wait   0005c710  29bd7f60   16384             0
>> 101
>>   LP-IPC            3  wait   0005c710  29c18f00  262144             0
>> 101
>>   LP-TX-Pak         3  wait   0005c710  29c21f00   32768             0
>> 101
>>   LP-RX-Pak         3  wait   0005c710  29c42f38  131072 <13%2010%2072>
>> 97  101
>>   LP-SYS-Mon        3  wait   0005c710  29c47f28   16384             0
>> 101
>>   LP-RTD-Mon        3  wait   0005c710  29c4cf08   16384             0
>> 101
>>   LP-Console        3  ready  20b636c0  29c6df78  131072 <13%2010%2072>
>> 0  101
>>   LP-CPU-Mon        3  wait   0005c710  29c96f40  163840             0
>> 101
>>
>>
>> MLX-4-2       Client GRE endpoint
>> xxxxxxxx -> xxxxx [Protocol:47]
>> **********************************************************************
>> [ppcr_rx_packet]: Packet received
>> Time stamp : 00 day(s) 00h 14m 33s:,
>> TM Header: [ 8026 2000 0000 ]
>> Type: Fabric Unicast(0x00000008) Size: 152 Parity: 2 Src IF: 0
>> Src Fap: 0 Dest Port: 0  Src Type: 0 Class: 0x00000000
>> **********************************************************************
>> Packet size: 146, XPP reason code: 0x00004747
>>
>> Traffic levels are very low , the connection to carrier A shows
>> approximately 40Mbps
>>
>> LP CPU on MLX-4-2 is
>>
>> SLOT  #:               LP CPU UTILIZATION in  %:
>>              in 1 second:  in 5 seconds:  in 60 seconds: in 300 seconds:
>>      1:        1             1              1               1
>>
>>
>> As a test I shut the port between MLX-4-1 and MLX-4-2  immediately CPU
>> usage dropped to 1% on MLX-4-1
>>
>>
>> No protocols over GRE tunnel we announce /24 and such and route throught
>> the tunnel using static route
>>
>>
>>
>> Show port on MLX-4-1 to MLX-4-2
>>
>>   Port is not enabled to receive all vlan packets for pbr
>>   MTU 1548 bytes, encapsulation ethernet
>>   Openflow: Disabled, Openflow Index 1
>>   Cluster L2 protocol forwarding enabled
>>   300 second input rate: 64599535 bits/sec, 61494 packets/sec, 0.74%
>> utilization
>>   300 second output rate: 2468 bits/sec, 4 packets/sec, 0.00% utilization
>>   82862765 packets input, 10844340289 bytes, 0 no buffer
>>   Received 25656 broadcasts, 27667 multicasts, 82809442 unicasts
>>   0 input errors, 0 CRC, 0 frame, 0 ignored
>>   0 runts, 0 giants
>>   NP received 82871502 packets, Sent to TM 82860777 packets
>>   NP Ingress dropped 10729 packets
>>   9484 packets output, 726421 bytes, 0 underruns
>>   Transmitted 127 broadcasts, 553 multicasts, 8804 unicasts
>>   0 output errors, 0 collisions
>>   NP transmitted 9485 packets, Received from TM 48717 packets
>>
>> Show port on MLX-4-2 to MLX-4-1
>>
>> Port is not enabled to receive all vlan packets for pbr
>>   MTU 1548 bytes, encapsulation ethernet
>>   Openflow: Disabled, Openflow Index 1
>>   Cluster L2 protocol forwarding enabled
>>   300 second input rate: 2416 bits/sec, 3 packets/sec, 0.00% utilization
>>   300 second output rate: 64189791 bits/sec, 61109 packets/sec, 0.74%
>> utilization
>>   5105571056 packets input, 760042160157 bytes, 0 no buffer
>>   Received 1874232 broadcasts, 5287030 multicasts, 5098409794 unicasts
>>   0 input errors, 0 CRC, 0 frame, 0 ignored
>>   0 runts, 0 giants
>>   NP received 5105571056 packets, Sent to TM 5105113719 packets
>>   NP Ingress dropped 457337 packets
>>   590086066756 packets output, 81697023432476 bytes, 0 underruns
>>   Transmitted 129784095 broadcasts, 208762136 multicasts, 589747520525
>> unicasts
>>   0 output errors, 0 collisions
>>   NP transmitted 590086072891 packets, Received from TM 590091974310
>> packets
>>
>>
>> Cheers
>>
>>
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>> foundry-nsp at puck.nether.net
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>
>
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