[c-nsp] 7206VXR Big CPU Increase After 12.4 Upgrade

Mon Mar 26 00:31:44 EST 2007

On Mon, 26 Mar 2007, Justin Shore wrote:

Does that router do QoS stuff or NBAR?  That seems to be the direction of 
routers with performance problems.

-Hank

> I thought I'd throw my experiences into the mix.  I have a 7206VXR w/ a 
> NPE-G1 terminating about 800 PVCs of DSL customers from 4 OC3s.  I had to do 
> an upgrade recently due to DHCP problems after an unexpected reboot.  I 
> upgraded to 12.4(11)T1 Adv IP w/ LI.  The router is now consuming less CPU 
> and less RAM.  The graphs seem to indicate that the internal temps may have 
> dropped by a degree or 2.  My experiences don't seem to be following what 
> others have reported.  I am curious to find out if my experience is simply a 
> fluke since I have another identical router performing a different function 
> that I need to upgrade in the very near future.
>
> Justin
>
>
> Rodney Dunn wrote:
>> Hank,
>> 
>> I researched this for you and talked with the TAC SR owner.
>> 
>> This performance hit is due to new packet classification mechanism
>> that went in to 12.4(11)T.
>> 
>> They are working to bring the performance back inline with the previous
>> classification code. The only problem apparently is that it will be
>> the next release of T as the changes are too large and complex to put
>> in the throttle.
>> 
>> I've asked them for some more clarification on what they are doing.
>> 
>> I'll pass it on when I get it.
>> 
>> Rodney
>> 
>> 
>> 
>> On Wed, Mar 21, 2007 at 08:59:58AM +0200, Hank Nussbacher wrote:
>>> Oldish thread:
>>> 
>>>> Re: 7206VXR Big CPU Increase After 12.4 Upgrade
>>>> 
>>>> For the benefit of the list and archives, we went back to 12.3.22 
>>>> yesterday
>>>> and our CPU levels dropped back to more like the previous levels.
>>>> 
>>>> The "%IF-4-BACKWARD_COUNTERS" have also disappeared since we went back to
>>>> 12.3.
>>>> 
>>>> Would recommend staying with 12.3 if you don't need a specific feature of
>>>> 12.4 as it is slightly more resource hungry (around 15 percent higher at
>>>> just over 200Mbps in our experience).
>>>> 
>>>> Thanks to everyone for their assistance,
>>>> Mark.
>>> Mark,
>>> 
>>> We hit the same problem (CPU doubled - see graph from mid-Feb at - 
>>> http://noc.ilan.net.il/stats/ILAN-CPU/tau-7206-cpu.html) going from 
>>> 12.4(4)T1 to 12.4(11)T1 so if you want try 12.4(4)T1  and your CPU should 
>>> not rise.   We have an open TAC case on this issue for 3 weeks now.
>>> 
>>> -Hank Nussbacher
>>> http://www.interall.co.il
>>> 
>>> 
>>>> ----- Original Message -----
>>>> From: "Rodney Dunn" <rodunn[at]cisco.com>
>>>> To: "Mark Taylor" <maillist[at]smashie.ision.co.uk>
>>>> Cc: <cisco-nsp[at]puck.nether.net>
>>>> Sent: Tuesday, January 30, 2007 4:02 PM
>>>> Subject: Re: [c-nsp] 7206VXR Big CPU Increase After 12.4 Upgrade
>>>> 
>>>> 
>>>>> There are a lot of new features in the switching vectors between
>>>>> 12.3 and 12.4 so you will see an increase in CPU.
>>>>> 
>>>>> In an upcoming 12.4(last)T release that will then be 12.5 mainline
>>>>> that is being changed so the net result will not be the same
>>>>> CPU impact as features are enabled that has traditionally been the
>>>>> case.
>>>>> 
>>>>> Can you post your configuration minus any senstive information in it?
>>>>> 
>>>>> Or unicast it to me...
>>>>> 
>>>>> Rodney
>>>>> 
>>>>> On Tue, Jan 30, 2007 at 02:01:39PM -0000, Mark Taylor wrote:
>>>>>> Hi,
>>>>>> 
>>>>>> We upgraded one of our 7206VXR NPE-G1's from 12.3(12a) to 12.4(12) this
>>>>>> morning to cover the recent security releases. We decided to make the
>>>>>> major
>>>>>> revision jump as we were reloading.
>>>>>> 
>>>>>> After the reload the box jumped from 20 percent cpu to 35 percent on 
>>>>>> the
>>>>>> new
>>>>>> 12.4(12) image and at the time there was around 75Mbps in each 
>>>>>> direction
>>>>>> of
>>>>>> traffic running through the box - so an immediate increase of 15 
>>>>>> percent.
>>>>>> 
>>>>>> Now there is about 185Mbps each way and cpu is at 65 percent. This 
>>>>>> would
>>>>>> have been about 45 percent before the change of image, so an increase 
>>>>>> of
>>>>>> 20
>>>>>> percent.
>>>>>> 
>>>>>> This is looking very much like cpu could potentially increase more
>>>>>> quickly
>>>>>> than traffic. The jump in cpu between images is beginning to concern me 
>>>>>> a
>>>>>> little. Has anybody else experienced this? Is it normal?
>>>>>> 
>>>>>> The box is a peering router running IPv4 and OSPF, a full BGP table 
>>>>>> from
>>>>>> one
>>>>>> upstream and about 20 other direct peers at a small IX and a few ACLs.
>>>>>> CEF
>>>>>> is still running.
>>>>>> 
>>>>>> I was hoping to get around 350Mbps through the box before running out 
>>>>>> of
>>>>>> cpu
>>>>>> and it was looking that way based on 12.3(12a). I guess I could go back
>>>>>> to
>>>>>> 12.3(22) which is fixed, assuming that the increase in cpu comes with
>>>>>> 12.4.
>>>>>> I just wanted to find out if this big jump in cpu between releases was
>>>>>> normal/expected.
>>>>>> 
>>>>>> Any help/experience appreciated.
>>>>>> Thanks,
>>>>>> Mark.
>>>>>> 
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