nanog mailing list archives
Re: Whats so difficult about ISSU
From: Saku Ytti <saku () ytti fi>
Date: Fri, 9 Nov 2012 23:00:59 +0200
On (2012-11-09 13:33 -0500), Pete Lumbis wrote:
I apologize, I realized I forgot a critical word in my reply. The new Cisco OSes are /NOT/ run to completion.
I did not notice that :). I assumed not was there, and was arguing that I thought IOS XE still is. I know XR and NX-OS aren't.
For IOS-XE we have Linux in charge of the scheduler with a multi-threaded IOSd process responsible for the control plane. I'm
I'm sceptical if this means there isn't normal IOS run-to-completion scheduler, certainly not all ios processes are separate threads to linux kernel? But I guess this is moving target. Would be interesting to hear how many threads, what are threads relative priorities, what runs in each thread etc. But anyhow just to hear it is threaded, is good news. Does this mean, IOSd can capitalize on multiple cores? (Something JunOS cannot do today)
critical IOSd process for example). The down side of this model is that control plane scaling, due to message passing, starts to have a lot of overhead. You can see this in the fact that the NX-OS routing scale is not where IOS-XE is.
Yup, luckily you guys stopped freescale pq3 and switch to xeon in ng nexus sup (unfortunately you also killed CMP, which I think every vendor should have). I think the overhead is worth it, built correctly you can scale horizontally and just keep throwing faster RP CPU at it. -- ++ytti
Current thread:
- Re: Whats so difficult about ISSU, (continued)
- Re: Whats so difficult about ISSU Oliver Garraux (Nov 08)
- Re: Whats so difficult about ISSU Phil (Nov 08)
- Re: Whats so difficult about ISSU Mikael Abrahamsson (Nov 08)
- Re: Whats so difficult about ISSU Jonathan Lassoff (Nov 08)
- Re: Whats so difficult about ISSU Jimmy Hess (Nov 11)
- Re: Whats so difficult about ISSU Juuso Lehtinen (Nov 08)
- Re: Whats so difficult about ISSU Saku Ytti (Nov 08)
- Re: Whats so difficult about ISSU Pete Lumbis (Nov 09)
- Re: Whats so difficult about ISSU Saku Ytti (Nov 09)
- Re: Whats so difficult about ISSU Pete Lumbis (Nov 09)
- Re: Whats so difficult about ISSU Saku Ytti (Nov 09)
- Re: Whats so difficult about ISSU Pete Lumbis (Nov 09)
- Re: Whats so difficult about ISSU Saku Ytti (Nov 09)
- Re: Whats so difficult about ISSU Pete Lumbis (Nov 09)
- Re: Whats so difficult about ISSU Saku Ytti (Nov 10)
- Re: Whats so difficult about ISSU Saku Ytti (Nov 10)
- Re: Whats so difficult about ISSU Randy Bush (Nov 10)
- Re: Whats so difficult about ISSU Saku Ytti (Nov 10)
- Re: Whats so difficult about ISSU Nick Hilliard (Nov 10)
- Re: Whats so difficult about ISSU sthaug (Nov 10)
- Re: Whats so difficult about ISSU Randy Bush (Nov 10)
- Re: Whats so difficult about ISSU Pete Lumbis (Nov 09)