It depends. With Linux it depends even more. Remember that scaling involves both a software and a hardware MP factor. On zSeries, we have some advantages from the hardware implementation. There are some workloads that scale very well on Linux for zSeries. Klaus Bergmann did a presentation at the last SHARE that gave some examples of excellent scaling on a 16-way. Of course I'm sure that's not the case for all workloads. :-)
As for scaling with virtual MP support. There is a small bump/cost in VM overhead in going from a virtual 1-way to a virtual n-way. However, after that the overhead is basically linear up to the maximum of 64 for a given virtual machine (though defining more virtual processors than real processors will not be of any benefit and may just add overhead). Bill Bitner - VM Performance Evaluation - IBM Endicott 607-752-6022 Internet: [EMAIL PROTECTED] Home Page: http://www.vm.ibm.com/devpages/bitner/
