[c-nsp] high cpu usage because of process switching on mlppp interface
Arda Balkanay
ardabalkanay at gmail.com
Mon Sep 3 01:47:04 EDT 2007
Hi
I haven't had a TAC SR yet about this issue, and i couldn't find the related
topic previously covered
in this group so sory for double opening of this kind of subject.
In my scenario i am running mpls over mlppp. this line is my pop uplink.
I could'nt get useful information about my problem from the command "show
cef interface" output.
According to your previous mail can you please send me the Bug ID, on the
other hand i can open a TAC case
for this issue, but before i should study cisco switching architecture (like
process switching fast switching and so on)
MTP-C72-02#sh cef interface mu 1
Multilink1 is up (if_number 55)
Corresponding hwidb fast_if_number 55
Corresponding hwidb firstsw->if_number 55
Internet address is 85.29.8.101/30
ICMP redirects are always sent
Per packet load-sharing is disabled
IP unicast RPF check is disabled
Inbound access list is not set
Outbound access list is not set
Interface is marked as point to point interface
Hardware idb is Multilink1
Fast switching type 7, interface type 94
IP CEF switching enabled
IP CEF Fast switching turbo vector
IP Null turbo vector
Input fast flags 0x0, Input fast flags2 0x0, Output fast flags 0x0, Output
fast flags2 0x0
ifindex 31(31)
Slot -1 Slot unit 1 Unit 1 VC -1
Transmit limit accumulator 0x0 (0x0)
IP MTU 1500
ADN-C38-01#sh cef interface Mu1
Multilink1 is up (if_number 21)
Corresponding hwidb fast_if_number 21
Corresponding hwidb firstsw->if_number 21
Internet address is 85.29.8.102/30
ICMP redirects are always sent
Per packet load-sharing is disabled
IP unicast RPF check is disabled
Inbound access list is not set
Outbound access list is not set
Interface is marked as point to point interface
Hardware idb is Multilink1
Fast switching type 7, interface type 94
IP CEF switching enabled
IP CEF Fast switching turbo vector
Input fast flags 0x0, Input fast flags2 0x0, Output fast flags 0x0, Output
fast flags2 0x0
ifindex 17(17)
Slot -1 Slot unit 1 Unit 1 VC -1
Transmit limit accumulator 0x0 (0x0)
IP MTU 1500
ADN-C38-01#
My interface configs are as follow:
MTP-C72-02#sh run int mu 1
Building configuration...
Current configuration : 262 bytes
!
interface Multilink1
description Maltepe - Adana MLPPP
mtu 1600
ip address 85.29.8.101 255.255.255.252
ip mtu 1500
mpls label protocol ldp
tag-switching mtu 1524
tag-switching ip
ppp multilink
ppp multilink group 1
ppp multilink mrru local 1604
end
MTP-C72-02#sh ppp mu
Multilink1, bundle name is ADN-C38-01
Endpoint discriminator is ADN-C38-01
Bundle up for 2d01h, 174/255 load
Receive buffer limit 25664 bytes, frag timeout 1000 ms
0/0 fragments/bytes in reassembly list
16890 lost fragments, 357474026 reordered
7820/896328 discarded fragments/bytes, 0 lost received
0xD2B4CA received sequence, 0x8EC33D sent sequence
Member links: 2 active, 0 inactive (max not set, min not set)
Se4/0:0, since 2d01h
Se2/3:0, since 2d01h
No inactive multilink interfaces
MTP-C72-02#sh run int ser 4/0:0
Building configuration...
Current configuration : 258 bytes
!
interface Serial4/0:0
description Tellcom 2Maltepe-Adana 2Mbps LL DATA NO:0107110068
mtu 1600
no ip address
ip mtu 1500
encapsulation ppp
load-interval 30
mpls label protocol ldp
tag-switching mtu 1524
tag-switching ip
ppp multilink group 1
end
MTP-C72-02#sh run int ser 2/3:0
Building configuration...
Current configuration : 264 bytes
!
interface Serial2/3:0
description Tellcom Maltepe-Adana 2Mbps LL DATA NO:0107110060
mtu 1600
no ip address
encapsulation ppp
load-interval 30
mpls label protocol ldp
tag-switching mtu 1524
tag-switching ip
fair-queue 64 16 0
ppp multilink group 1
end
MTP-C72-02#sh run int ser 4/0:0
Building configuration...
Current configuration : 258 bytes
!
interface Serial4/0:0
description Tellcom 2Maltepe-Adana 2Mbps LL DATA NO:0107110068
mtu 1600
no ip address
ip mtu 1500
encapsulation ppp
load-interval 30
mpls label protocol ldp
tag-switching mtu 1524
tag-switching ip
ppp multilink group 1
end
MTP-C72-02#sh run int ser 2/3:0
Building configuration...
Current configuration : 264 bytes
!
interface Serial2/3:0
description Tellcom Maltepe-Adana 2Mbps LL DATA NO:0107110060
mtu 1600
no ip address
encapsulation ppp
load-interval 30
mpls label protocol ldp
tag-switching mtu 1524
tag-switching ip
fair-queue 64 16 0
ppp multilink group 1
end
ADN-C38-01#sh run int mu 1
Building configuration...
Current configuration : 244 bytes
!
interface Multilink1
description Adana - Maltepe MLPPP
mtu 1600
ip address 85.29.8.102 255.255.255.252
ip mtu 1500
mpls label protocol ldp
mpls ip
mpls mtu 1524
ppp multilink
ppp multilink group 1
ppp multilink mrru local 1604
end
ADN-C38-01#sh ppp mu
Multilink1, bundle name is MTP-C72-02
Endpoint discriminator is MTP-C72-02
Bundle up for 2d01h, total bandwidth 4096, load 186/255
Receive buffer limit 25664 bytes, frag timeout 1000 ms
0/0 fragments/bytes in reassembly list
42246 lost fragments, 185970460 reordered
35687/1919036 discarded fragments/bytes, 0 lost received
0x9256EA received sequence, 0xD6C17F sent sequence
Member links: 2 active, 0 inactive (max not set, min not set)
Se0/0/1:0, since 2d01h
Se0/0/0:0, since 2d01h
No inactive multilink interfaces
ADN-C38-01#sh run int ser 0/0/0:0
Building configuration...
Current configuration : 241 bytes
!
interface Serial0/0/0:0
description Tellcom Adana-Maltepe 2Mbps LL DATA NO:0107110060
mtu 1600
no ip address
ip mtu 1500
encapsulation ppp
load-interval 30
mpls label protocol ldp
mpls ip
mpls mtu 1524
ppp multilink group 1
end
ADN-C38-01#sh run int ser 0/0/1:0
Building configuration...
Current configuration : 265 bytes
!
interface Serial0/0/1:0
description Tellcom 2Adana-Maltepe 2Mbps LL DATA NO:0107110068
mtu 1600
no ip address
ip mtu 1500
encapsulation ppp
no ip route-cache cef
load-interval 30
mpls label protocol ldp
mpls ip
mpls mtu 1524
ppp multilink group 1
end
Thanks for your help
Kind Regards
Arda
On 8/29/07, Rodney Dunn <rodunn at cisco.com> wrote:
>
> 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
> > _______________________________________________
> > cisco-nsp mailing list cisco-nsp at puck.nether.net
> > https://puck.nether.net/mailman/listinfo/cisco-nsp
> > archive at http://puck.nether.net/pipermail/cisco-nsp/
>
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