Colin, a really good performance monitor that kept full history data
would have been of great assistance.
Colin Allinson wrote:
We have a very large VM system that runs in a partition on a Z9 with 7
dedicated processors and 24G/4g stor/xstor
We can, at peak times, get up to the upper 9x% level but this week we
have been running in the 60-75% range
Earlier this afternoon I had a user complaining about performance and I
could see the following (notice PROC 0000) :-
AVGPROC-062% 07
XSTORE-000000/SEC MIGRATE-0000/SEC
MDC READS-000001/SEC WRITES-000000/SEC HIT RATIO-100%
PAGING-1/SEC STEAL-000%
Q0-00004(00000) DORMANT-00253
Q1-00018(00000) E1-00000(00000)
Q2-00006(00000) EXPAN-002 E2-00000(00000)
Q3-00048(00000) EXPAN-002 E3-00000(00000)
PROC 0000-082% CP PROC 0006-057% CP
PROC 0001-059% CP PROC 0002-059% CP
PROC 0003-060% CP PROC 0004-059% CP
PROC 0005-059% CP
LIMITED-00000
Ready; T=0.01/0.01 13:23:56
I have seen this behaviour before when :-
a) The system is very busy and we are approaching 100% keeping the
scheduler over employed.
b) We are getting streaming CP messages (i.e. device retries).
c) Huge amounts of data are being spooled from some userid
I have checked and, as far as I can tell, none of these were relevant at
the time.
Can anyone suggest any other likely conditions that would cause such a
heavy overload on processor 0?
btw: The situation improved (with an even balance of processor usage
being restored) over a period of about 45 minutes.
*
Colin Allinson**
VM Systems Support*
Amadeus Data Processing GmbH
