Re: Subsystem and memory pools

Hi Nathan

I look at things like length of time the jobs is likely to run; i tend to
keep jobs with shorter activity cycles (e.g.green screen type stuff
separate from query type workload)
Basically for the stuff that is running longer I try and route it to a sbs
with a class with a higher timeslice so the job does not get paged out as
often; generally speaking the job priority on this stuff is probably lower.

If the jobs are all lumped into one pool/subsystem and have the same class
and timeslice then longer running jobs are getting paged out at the same
rate as the shorter running jobs; the effect being that they might have to
be paged in/out more frequently in order to complete.

IN terms of java jobs I have set up susbsystems and related pools for
websphere (for example) that were sized around the websphere server to
ensure it wasn't paged in and out of memory as the jobs/connections that
were dependent on websphere - e.g. database connections - were also
affected by this.

On Sat, Dec 16, 2017 at 6:11 AM, Nathan Andelin <nandelin@xxxxxxxxx> wrote:

On Fri, Dec 15, 2017 at 8:52 AM, Jim Oberholtzer <
midrangel@xxxxxxxxxxxxxxxxx> wrote:

The rule with memory is simple; keep like workloads together, so
interactive
with interactive, batch with batch, SQL ...

In regard to "like workloads", I interpret that to mean similar CPU and
memory requirements. When you look at Jobs that are running on the system,
you might notice a Java process that is consuming 200-400 meg of "temporary
storage" and and the CPU time consumed may be tens of thousands of
milliseconds.

Then you look at a 5250 Job. The temporary storage might be 2 meg. Say the
user is viewing a monolithic source member in SEU. Every time the user
presses the PgDn key a request is sent to the server to get the next page.
Every 10-20 pages or so the Job is shown to consume a millisecond of CPU
time.

So, you don't want that Java Job paging in and out of memory.

Consider PHP Jobs. Running 200 of them concurrently has been known to
destabilize and bring down entire systems running Windows and Linux. It may
make sense to run PHP in separate subsystems and memory pools.
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