CF doesn't *always* take 100% of CPU power. It depends. 100% is taken
when only dedicated processors are assigned to CF LPAR. There is a
feature called Dynamic CF Dispatching (DCFD), which changes CF behavior
on shared engines. In some cases you can switch DCFD off using DYNDISP
command.
Regarding to the topic: IMH it is better just to define dummy OS LPAR,
it is not required to IPL any OS on it. Activated LPAR is enough. Then
you can hard-cap (*) your prod LPAR at the weight you set.
(*) or soft-cap - in this case you *must* have spare cycles on CPC.
--
Radoslaw Skorupka
Lodz, Poland
Gil Peleg wrote:
There was a similar thread about this issue a couple of months ago. Since
then I have been using a CF LPAR to guard 40% of the machine's MSUs by
defining it to share all our CPs, and hard-cap the CF LPAR at weight 40 out
of a 100 total.
Lately I am seeing a very large difference between the LPAR BUSY TIME PERC
and the MVS BUSY TIME PERC fields in the RMF CPU Activity report. The
difference is over 20% at peak hours. This was not the case before I started
using "CF capping".
The CF LPAR used to guard MSUs has the highest weight on the machine. Taking
under consideration the polling nature of CF LPARs, keeping the CPs busy all
the time, I am starting to think this has performance implications I have
overlooked before. Does this make sense?
Thanks,
Gil.
On 12/30/05, Gil Peleg <[EMAIL PROTECTED]> wrote:
Hi Bruno,
Lately I am starting to wonder how perfectly this method realy works.
On 12/29/05, Bruno Sugliani <[EMAIL PROTECTED]> wrote:
The easiest way is to create a CF with the amount of MIPS you do not
want
and leave the 200 mips to your lpar .( it works perfectly )
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