Jan Vanbrabant wrote:
*** Cross-posted in the IBM-MAIN & IMS-L listservers) ***
Hi,
Either I’m getting old (or at least too old to understand), or I’m stupid, or
I’m too tired to understand (after a long day gazing at my laptop screen) …
One way of doing accounting for billing purposes in IMS is based on the DLRTIME
field in the Application termination accounting log record (x’07’).
(There’s also DLREXTIM field, which is new in IMS V10, while we are V9. Anyway
this is not important in this discussion.)
IMS TYPE07 log record CPU timer-unit field, DLRTIME, indeed allows to capture
the CPU time used by a running transaction. This execution time is expressed in
so-called “Timer Units (TU)”.
TU is a z/OS notion (STIMER-, STIMERM-, TIME-, TTIMER-macros), not an IMS
concept.
ASKQQA item RTA000060992 (19920318) about “TIMER UNITS (TU) conversion to CPU time”
says: <One timer unit (TU) is approximately 26.04166 microseconds. You can
multiply that value with the number of TUs reported in the type x'07' log record.>
Looking into the latest SA22-7607-13 zOS V1R9.0 MVS Programming Assembler
Services Reference Vol 2 (IARR2V-XCTLX) (iea2a981) (April 2008) timer units
still are “approximately 26.04166 microseconds per unit” …
After more than 16 years ago with a couple of technology changes & much faster
processor cycles, a TU still equals 26.04166 microseconds???
There is something I don’t understand ….
The real question is: how can I take into account the technology evolution from a pre-z to a z machine (for example) in the accounting/billing scheme?
Pls shed some light in the darkness of my mind.
Jan
The Timer Units are based on the S360 timer which was a word in low
storage (80 X'50'). It was updated based on the line frequency (60 hertz
in the US). It does not change with the speed of the CPU, and so is
constant. The Timer no longer exists (replaced by the TOD clock), but
the TU still lives on in lots of software.
As for taking technology evolution into account in your billing system,
it depends on what you want to do. You can adjust the time to some
standard machine speed, or adjust billing rates as machines get faster.
Billing can be a complicated thing. If you are trying to make the
charges the same for the same job, you will find that it is not
completely repeatable even on the same machine, much less on different
ones.
--
Richard
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