On Tuesday, 02/10/2004 at 09:17 CST, "Little, Chris"
<[EMAIL PROTECTED]> wrote:
> at one time, was IBM recommending differently?  i went to an
introduction to
> z/VM several years ago and the instructor was recommending 4 virtual
CPU's
> no matter how many real CPU's existed.  He said that VM's
multiprocessing
> capability was superior to linux so it was better to queue processes to
VM.

The number of virtual CPUs should not exceed the number of real CPUs. Each
extra virtual CPU creates overhead that is exchanged for the advantages of
parallelism.  If you exceed the number of real CPUs, then the overhead is
incurred, but without any advantage.

Linux's n-way capabilities continue to improve.  Anything you heard about
Linux scalability "several years ago" is ancient history, only to be
quoted at symposia discussing "Linux - The Early Years".  ;-)

Alan Altmark
Sr. Software Engineer
IBM z/VM Development

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