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

[Justin Shore]

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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