Mark Zelden wrote:
On Fri, 5 Jan 2007 18:08:32 +0100, R.S. <[EMAIL PROTECTED]>
wrote:
IMHO the difference between 10GB and 60GB won't be perceptible, while
difference between 8 and 10 GB will be small but perceptible.
What makes you say that? It depends on the release, if you are
running 64-bit and even your maintenance level as to what happens
and how often with RSM UIC updating and page replacement algorithms.
Minor changes are often made and sometimes not so minor. Examples
are the UIC update changes that were made for ARCHLVL2 and all of the
changes that were were made in z/OS 1.8. Also, even if you aren't
"paging" that doesn't mean there isn't contention for 24-bit or 31-bit
storage areas that drive page stealing routines.
Mark,
I respect your opinion (all of them), but I don't understand how the
last sentence is related to overhead caused by too much memory.
BTW: I remember an issue with Windows95 and performance impact, when
memory was upgraded from 64MB to 80MB. The impact was small, but
perceptable. It was caused by VX chipset on the motherboard, the chipset
was able to L2-cache only first 64MB of memory. Windows used high
addresses for the OS residence - so it was placed in non-cacheable
memory. Obviously other motherboards were not affected, but VX was very
popular and common opinion was "Windows slows down when too much memory
is present".
Regards
--
Radoslaw Skorupka
Lodz, Poland
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