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

[Rodney Dunn]

In the interim if there are not new features or hardware you need
in 12.4(11)T it's better to remain on a pre-12.4(11)T image if
possible.

It seems, and we are getting more clarification on it, the impact
is worse when you have NBAR configured.

Rodney

On Fri, Mar 23, 2007 at 10:54:47AM -0400, 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.
> > > >>
> > 
> > _______________________________________________
> > 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/
> _______________________________________________
> 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/