[c-nsp] high cpu usage because of process switching on mlppp interface
Rodney Dunn
rodunn at cisco.com
Wed Aug 29 15:42:51 EDT 2007
Do you have a TAC SR open on this?
I just saw someone ask this a few days ago and I told them it's
a bug.
We support CEF switching of data over a MLPPP bundle with
MPLS.
Are you running MPLSoMLPPP or are you just running the MLPPP
interface in a VRF?
> MTP-C72-02#sh inter mul 1 switching
> Multilink1 Maltepe - Adana MLPPP
> Throttle count 0
> Drops RP 752707 SP 0
> SPD Flushes Fast 0 SSE 0
> SPD Aggress Fast 0
> SPD Priority Inputs 259 Drops 0
>
> Protocol IP
> Switching path Pkts In Chars In Pkts Out Chars Out
> Process 50148189 395174672 261949 26235771
> Cache misses 0 - - -
> Fast 1325 105874 12194 724886
> Auton/SSE 0 0 0 0
>
> Protocol Tag
> Switching path Pkts In Chars In Pkts Out Chars Out
> Process 79390997 3601460527 5116 538398
> Cache misses 0 - - -
> Fast 0 0 87354606 4071850482
> Auton/SSE 0 0 0 0
shows you are process switching a ton of your IP traffic and all
of the inbound MPLS traffic.
Outbound your mpls traffic is fine so we need to look at the inbound
switching vectors coming in the MLPPP interface.
As Bruce said can you get 'sh cef in mu 1'?
Also, post the configs of the mlppp interface as well as the other
interfaces this traffic will go out of once it comes in the MLPPP
interface?
Rodney
On Wed, Aug 29, 2007 at 03:15:19PM +0300, Arda Balkanay wrote:
> Hi
> i have a problem about high cpu usage on a 7206 VXR NPE-G1 because of
> process switching on a multilink ppp interface.
>
> I have two E1 interfaces between 7206 and 3845 (below MTP-C72-02 indicates
> 7206 and ADN-C38-01 indicates 3845).
> I've bundled these two E1 interfaces. And when the amount of traffic rised
> CPU usage also increased about 15 percent more.
> "show proc cpu" output points increase at the processes of ip input and tag
> input.
> MTP-C72-02#sh proc cpu sorted
> CPU utilization for five seconds: 78%/64%; one minute: 79%; five minutes:
> 81%
> PID Runtime(ms) Invoked uSecs 5Sec 1Min 5Min TTY Process
> 68 39242000 258183793 151 8.92% 8.20% 8.40% 0 IP
> Input
> 109 25093708 119681214 209 6.88% 7.37% 7.79% 0 Tag Input
>
>
> When i looked at the switching status of the interface i saw that 7206 is
> using process switching while 3845 uses fast switchig (especially for mpls)
> MTP-C72-02#sh inter mul 1 switching
> Multilink1 Maltepe - Adana MLPPP
> Throttle count 0
> Drops RP 752707 SP 0
> SPD Flushes Fast 0 SSE 0
> SPD Aggress Fast 0
> SPD Priority Inputs 259 Drops 0
>
> Protocol IP
> Switching path Pkts In Chars In Pkts Out Chars Out
> Process 50148189 395174672 261949 26235771
> Cache misses 0 - - -
> Fast 1325 105874 12194 724886
> Auton/SSE 0 0 0 0
>
> Protocol Tag
> Switching path Pkts In Chars In Pkts Out Chars Out
> Process 79390997 3601460527 5116 538398
> Cache misses 0 - - -
> Fast 0 0 87354606 4071850482
> Auton/SSE 0 0 0 0
>
>
> ADN-C38-01#sh inter mu 1 switching
> Multilink1 Adana - Maltepe MLPPP
> Throttle count 0
> Drops RP 0 SP 0
> SPD Flushes Fast 0 SSE 0
> SPD Aggress Fast 0
> SPD Priority Inputs 242 Drops 0
>
> Protocol IP
> Switching path Pkts In Chars In Pkts Out Chars Out
> Process 32394 2110804 17595 1260300
> Cache misses 0 - - -
> Fast 559376 60411948 154 8439
> Auton/SSE 0 0 0 0
>
> Protocol Tag
> Switching path Pkts In Chars In Pkts Out Chars Out
> Process 7106 398899 10784 539203
> Cache misses 0 - - -
> Fast 87130476 3140243335 80454345 488241675
> Auton/SSE 0 0 0 0
>
>
> When i checked "show ip interface" output i can see that fast swithing is
> enabled but i didn't understand why 7206 uses process switching while 3845
> uses fast
> swithcing with the same multilink interface configuration. ip interface
> output is as follows:
>
> MTP-C72-02#sh ip int mu 1
> Multilink1 is up, line protocol is up
> ...
> IP fast switching is enabled
> IP fast switching on the same interface is enabled
> IP Flow switching is disabled
> IP CEF switching is enabled
> IP CEF Fast switching turbo vector
> IP Null turbo vector
> IP multicast fast switching is enabled
> IP multicast distributed fast switching is disabled
> IP route-cache flags are Fast, CEF
> ...
> MTP-C72-02#
>
> ADN-C38-01#sh ip int mu 1
> Multilink1 is up, line protocol is up
> ...
> IP fast switching is enabled
> IP fast switching on the same interface is enabled
> IP Flow switching is disabled
> IP CEF switching is enabled
> IP CEF Fast switching turbo vector
> IP multicast fast switching is enabled
> IP multicast distributed fast switching is disabled
> IP route-cache flags are Fast, CEF
> ...
> ADN-C38-01#
> 7206 uses ios c7200-jk9s-mz.123-14.T3.bin and 3845 uses
> c3845-spservicesk9-mz.124-8b.bin
>
>
> Do you have any idea about this situation ?
>
>
> Kind Regards
> Arda
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