Hi fellow Listers !

Carl wrote :

> Could someone please explain/expand on the memory clock cycle field in
> glance?  I have no idea what this field is or at what point it indicates
a
> potential problem.
>
> Carl McNamee
> Systems Administrator
> Billing Concepts

It's the number of times (or cycles) that the Memory Manager scans all
physical memory to find available pages, in a given unit of time, which is
one hour. On average, I would say that any figure permanently above 30,
i.e. one cycle every 2 minutes, is a hint there might be some memory
pressure.You can view physical memory as a circle going from address 0 to
address <max_physical_memory_address>, whatever that value is, and back to
0, in a circular way. Of course, the pointer that scans the memory will
have to skip frozen/locked pages (core MPE, I/O system, etc), thus having a
tendency to scan memory a bit faster as the percentage of frozen/locked
pages increases.

This value is supposed to remain slow because, as MPE/iX allocates memory
pages according to a not-necessarily-contiguous scheme, the scan pointer is
supposed to move relatively slow, except for the occasional burst of
activity.

And, as always when dealing with performance issues, this measure has to be
confirmed by another one. My suggestion is to have a look at the Memory
Manager disk I/O, also in Glance, in the Disk screen. Depending on box type
and physical I/O config, any figure permanently above 5-10 is also a strong
indication of memory pressure.

And you can also throw in the Memory Manager part of CPU consumption, which
should always be below 2-3 %.

Please feel free to get back to me, either on the list or in private, for
more details as needed.

Take care,

Christian Lheureux
Responsable du Departement Systemes et Reseaux
Head of Systems and Networks Department
APPIC R.H.
HPConnect Systems Integrator / HP3000 Expert / HP e-Partner
Tel : +33-1-69-80-97-22   /   Fax : +33-1-69-80-97-14