Re: [MI400] What is main memory resident?

["Alexei Pytel" <pytel@xxxxxxxxxx>]

Actually, Mark is right.
There are two gotchas though:
1) use a separate pool for the object, because if there is other activity
in the pool, object pages can be paged out
2) do not use shared pools, because if you do 1) above for a shared pool,
then there will be no activity in the pool (no threads running), which will
make this pool the primary candidate for reducing by Performance Adjuster.

Usual trick is to start an empty subsystem with a private pool defined, big
enough for an object and then
SETOBJACC OBJ(<library>/<object>) OBJTYPE(<type>) POOL(<subsystem> <pool
number in subsystem>)

Performance Adjuster does not touch private subsystem pools.

    Alexei
always speaking for myself




                      "Leif Svalgaard"
                      <leif@leif.org>          To:       <mi400@midrange.com>
                      Sent by:                 cc:
                      mi400-admin@midra        Subject:  Re: [MI400] What is 
main memory resident?
                      nge.com


                      07/26/2002 09:53
                      AM
                      Please respond to
                      mi400





From: Mark Waterbury <mark.s.waterbury@worldnet.att.net>
> The idea is, if you really need high-performance and you want the
> object loaded by SETOBJACC to "stay" in memory, you can just
> create a separate memory pool, using OS/400 storage management.
> One of the parameters on the SETOBJACC command is which
> POOL you want to "bring" the object pages into.  Then, so long as
> no one else is using that POOL, and the pool is sufficiently large,
> then none of the pages for your object will get "paged out", and
> so, the effect can be almost like "pinning" the pages in memory.

Mark, I don't think any of your suggestions would work. Sure, they
would bring in the pages, but would not block the system from
"dropping" them again as soon as other pages are needed by anybody
else. I think the paging takes place so far below the work management
layer that you can't influence it as you suggest. Now, I could be wrong,
so let's get some input from IBMers (current or ex-) on this.

_______________________________________________
This is the MI Programming on the AS400 / iSeries (MI400) mailing list
To post a message email: MI400@midrange.com
To subscribe, unsubscribe, or change list options,
visit: http://lists.midrange.com/cgi-bin/listinfo/mi400
or email: MI400-request@midrange.com
Before posting, please take a moment to review the archives
at http://archive.midrange.com/mi400.