To say it with other words: CP is not really dispatching userids, but it
dispatches virtual CPUs, and only virtual CPU's that want to work (CP knows
when a virtual CPU places itself in wait, so it won't dispatch "sleeping"
CPUs).
An example: suppose you have 3 Linuxes, each with 2 virtual CPUs (that want
to work), and 2 CMS users (eg PERFSVM and OPERATOR) that also want to work
==> CP has 3x2 and 2x1 = 8 virtual CPU's to dispatch on 3 IFLs

2010/1/5 Alan Altmark <[email protected]>

> On Tuesday, 01/05/2010 at 12:25 EST, "Harris, Nick J."
> <[email protected]> wrote:
>
> > According to our performance product we do NOT need an additional IFL at
> this
> > time but it was included as part of the z10 upgrade so I wanted to
> utilize it.
>
> It will be utilized even though you do not define three *virtual* CPUs. CP
> will be able to run three virtual CPUs at once instead of only two.  With
> virtual 2-ways, you ensure that no single guest is using all three CPUs at
> the same time.
>
> Alan Altmark
> z/VM Development
> IBM Endicott
>



-- 
Kris Buelens,
IBM Belgium, VM customer support

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