[Info-vax] Raxco VMS Tuning Seminar Notes

[Neil Rieck]

>
> Right, the only reason to do more aggressive memory management /
> reclamation is when you're in a memory starved environment.  However,
> just out of curiosity, do you use AWSA on the DS20e?  According to the
> RAXCO bible, it was encouraged for use in ALL (or nearly all)
> circumstances.
>

First off, everyone uses AWSA-expansion so I think you are asking
whether I use AWSA-reduction on my DS20e and the answer is no. Why?
I've got 3 GB of RAM so it makes no sense not to use it. Also,
swapping on a VAX was much more expensive than on Alpha and Itanium.

BTW, the "Raxco Bible" you are referring to describes rule-of-thumb
rules for an older technology (VAX) from an older time.
1) Swapping was more expensive on VAX than it is on Alpha.
2) VMS tuning parameters are still there but are used in a different
way on modern systems. For example, VAX tuning emphasized a large
FREELIST while big memory Alpha tuning (with large memory) emphasizes
a smaller FREELIST. With a large FREELIST, a shrinking process would
surrender pages to the FREELIST then soft-fault them back as needed.
Getting the right balance between soft-fault (painless) and hard-fault
(more painful) on VAX was preferable to swapping (dreadful).

Alpha Example: When I run with mostly default autogen settings, the
script sees me running 3 GB of memory then sets FREELIM = GROWLIM =
BORROWLIM which is way different than what you would have seen on a
VAX 20 years ago.

NSR