Author: Pawel LeszczynskiPawel Leszczynski Date: Jun 16, 2008 13:18
Hello everybody,
recently, as our production LPARs apetite for CPU has grown meaningful
(we are in process connecting succesive branches of bank to new application),
our sysprogs decided to simply put online subsequent processors to this LPARs.
We ended in 12 processors assigned to each of them.
I would like to know if 12 processors/LPAR is not too many, i.e.
measure how much capacity it 'wasted' that way.
I realise that RMF monitor III shows overhead on let's say LPAR dispatching
but I guess that's a different story.
Where is this CPU 'wasted'?
That's my naive thinking (please correct me):
Serialization beetween processors within LPAR is done via locks.
Requests for spin lock (from this point of view) are 'CPU-wasting' - processor
have to wait actively (if wait at all) for obtaining such a lock.
Where are other places???
Is there any tool which sums such 'CPU-wasted' cycles and shows how many
percent of CPU is 'wasted' in such way?
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