Re: Performance Monitor question

Discussion created by ca.portal.admin on Jun 26, 2007
Kay - here's a couple of entries from our ""IDMS Tuning Diary"" that you
may find to be of interest - given some of your recent posts. One of
things to remember is that PMAM, PMIM both requires at least STAT
COLLECT - so your BASELINE overhead will be whatever that option costs
at your site (between 9 and 18%) for us - and then you get the
incremental overheads for (for example) PMIM on top of that.

HTH - cheers - Gary

8. System Statistics
Status: Implemented in PRO 27.aug.1999
Scheduled for:

Next Action:

Result: Reduced CPU by 18% from 27.aug.1999

8.1 Discussion
Saw a 20% CPU saving when turned off at CAA - decided to try at JIS
also. First got approval from JIS Finance Committee - as this will
impact the way in which chargeback will operate. There are papers
written on this subject somewhere on the LAN.

8.2 Statistics Collection turned OFF - 27.aug.1999
At the request of Gary changed the sysgen system statement :
From :
To :
SMF stats won't be written unless reversed.

8.3 Statistics Collection- NOUSER when turned ON - oct.2001
Discovered that there is a 10% saving at JIS when we turn statistics ON
- but when we specify NOUSER to suppress the breaking out of USER mode
and SYSTEM mode time as separate figures. Rather, the CV just gives the
""total"" cpu per task as ""system mode"".

Unless doing tuning where we needed to know where the performance gains
were taking place (i.e. system or application) - there is no need to
break out USER mode time.

12. Remove PMIM from PRO on SYSJ
Status: Change in as scheduled 2.June - WR#6593
Scheduled for:

Next Action:

Result: 1.5% CPU reduction

12.1 Discussion
Anticipate CPU savings.

30. System Trace - July.2006 - adds approx 7%

30.1 July.2006

The system trace facility was enabled for IDMSP at the beginning of July
in response to a recurrence of a problem which resulted in IDMSP
abending on June 29th.

My best estimate of the cost impact of the additional overhead, based on
a comparison of one day's statistics before tracing was enabled with one
day's tracing after, is that the overhead is approximately 7%, which
will add approximately $17,800 to our CPU cost for a full month.

The intention was to leave the trace on until either the problem was
fixed, or after a couple of months if there was no recurrence of the

30.2 11.August.2006

I (Paul Mak @ OutSourcer) took the liberty to turn SYSTRACE OFF in RES,
PED, TRN and PRO leaving it in DEV until further advice from you. One
point to note is that we can dcmt vary systrace on entries = 9999 to
turn it on dynamically for the duration of the CV session or until it
gets vary systrace off dynamically. That would be useful if we could
recreate the problem within a short interval.

Gary Cherlet
Justice Technology Services
Department of Justice, SA Government
Telephone +61 (0)8 8226 5199
Facsimile +61 (0)8 8226 5311
Mobile +61 (0)41 333 1613

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