On Thursday, 07/08/2010 at 11:02 EDT, Martin Zimelis 
<[email protected]> wrote:
> Unless you're max'ing out these virtual machines by consuming 100%
> of a real processor, it should be as simple as increasing their SHARE
> values.

To finish the thought, adding virtual CPUs to a guest does not add CPU 
capacity to a guest; SET SHARE does.  Adding another virtual CPU may allow 
the guest to better use the CPU capacity it has been given, increasing 
throughput or decreasing response time, or it may actually slow the guest 
down.  It all depends on the application.

A good performance monitor will tell you if a guest is constrained, and 
why.  Of course, one must measure, change, and measure again to ensure 
that the changes had the desired effect.  Sometimes after you release the 
hounds, you discover that the yard is a mess.

Alan Altmark
z/VM Development
IBM Endicott

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