[157821] in North American Network Operators' Group

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Re: Whats so difficult about ISSU

daemon@ATHENA.MIT.EDU (Saku Ytti)
Fri Nov 9 17:08:04 2012

Date: Sat, 10 Nov 2012 00:07:45 +0200
From: Saku Ytti <saku@ytti.fi>
To: nanog@nanog.org
In-Reply-To: <CAB0xJrO28FjyV5PWE-iQEkmWbG4efZHp_KHAHcdj36Gppj2D5Q@mail.gmail.com>
Errors-To: nanog-bounces+nanog.discuss=bloom-picayune.mit.edu@nanog.org

On (2012-11-09 16:58 -0500), Pete Lumbis wrote:
 
> I do not believe that the linux scheduler is run to completion, but to
> be honest I'm not 100% certain. I know a big reason for IOS-XE was to

It certainly is not, I'm not proposing it is. I'm saying it is bit of a
stretch to believe that IOSd does not have own legacy scheduler and memory
management as pulling that switch would have been quite major rework.

> be able to operate in multicore environments. From a high level you
> have IOSd as a process with each traditional process (BGP, OSPF, IP
> Input) as a thread within IOSd. Overall IOS-XE is Linux managing a few
> processes: IOSd, FMan-RP, CMan-RP (and a few others) FMan deals with
> adjacencies and CMan deals with modules/cards and IOSd all the
> interesting stuff. Since Linux is the piece actually running the show
> IOS-XE gets all the memory management and scheduling benefits that
> linux has.

So each IOSd process 'show proc cpu' are separate threads to linux?

-- 
  ++ytti


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