Different SUBTASK EFFECTIVENESS figures between machines
Article ID: 186818
Updated On:
Products
Issue/Introduction
There is a difference in CPU effectiveness for the same IDMS region between two machines.
Question is -- is this normal? Does it have something to do with different architecture?
D SUBTAS EFF *** Subtask display *** Subtask % CPU Name Elapsed time Total CPU time effectiveness -------- -------------- -------------- ------------- MAINTASK 00:00:14.9540 00:00:00.4021 02 SUBT0001 00:02:09.7507 00:00:21.9015 16 SUBT0002 00:34:21.3877 00:22:11.5570 64 -------- -------------- -------------- ------------- Totals 00:36:46.0924 00:22:33.8606 61
D STAT SYS 12:58:29.71 20/077 Current Time 00:19:05.93 Tot Sys Time 13:19:11.24 20/075 Startup Time 00:03:26.82 Tot User Time TASKS: 66475 Processed 243 Abended 47 Max Tasks 4782 System 0 Runaway 0 Times At Max 8 Deadlocks 6 Dead Victims TRANS: 151422 Processed 108283 Norm Cmp 103 Max Conc 6229 Ext Proc 6179 Ext Norm 8 Ext Conc 10 Max Erus 0 Dist Proc 0 Dist Norm 0 Dist Conc DATABASE: 35342552 Calls 514547495 Pages Rqst 555031959 Recs Rqst 0 Buff Wait 34226065 Pages Read 123495910 Recs Cur R/U 2245440 Page Writ 169096 Calc Noflo 209328 Via Noflo 672830765 Tot Locks 2061 Calc Ovflo 57925 Via Ovflo 6866 Frag Stord 0 Recs Reloc INDEX: 16582 SR8 Splits 15907 SR8 Stores 42 SR7 Stores 143 SR8 Spawns 15527 SR8 Erases 42 SR7 Erases 2821 Orph Adopt 2352527 Ix Searches 1 Min Level 8027787 Lvls Srchd 7 Max Level SQL: 3797982 Commands 6268769 Tupls Fetched 169868 Rows Inserted 0 AM Recomp 446122 Rows Updated 173222 Rows Deleted 95120 Sorts 1 Sort Min 1273784 Tuples Sorted 36972 Sort Max JOURNAL: 0 Buff Waits 0 User Putjrnl Page 376073 0-10 24870 11-20 20546 21-30 80161 31-40 16331 41-50 Dist 15818 51-60 14333 61-70 25830 71-80 107022 81-90 949999 91-100 INTERNAL: RLEs RCEs DPEs Stack 5596 5538 681 967 HWM 8000 8000 1100 3200 Sysgen Threshold 0 0 0 Times Exceeded STORAGE: 8604995 Gets 8518240 Frees Gets for type 0 PGFIXs 0 PGFREEs 3266699 DB 0 Pages Fxd 0 Pages Freed 100 SHK 7601777 Scan 1 0 PGRLSEs 1 SHR 1003218 Scan 2 0 Pages Relsd 1271055 SYS 64301 USK 0 SOS COUNT 4002839 USR PROGRAM: Act Loads Pages Load Wait/Space Non-Reent 3 8 0 Reent 40 962 0 XA Non-Reent 110 1042 0 XA Reent 11148 4306746 0 SCRATCH: 286550 Gets 293125 Puts 292860 Dels QUEUE: 28718 Gets 27146 Puts 4824 Dels 34 Task AutoSt TIME: 4705091 Gets 180327 Post 84 Started Tasks 3859 Wait 180411 Canc USERS: 66 Signed on 95 HWM
Environment
Release: All supported releases.
Resolution
The lower subtask effectiveness on the enterprise class machine could be normal. It means IDMS is not getting the amount of CPU it needs and this doesn't necessarily mean that it will be unresponsive with slow performance.
CPU Effectiveness represents the amount of CPU time an IDMS CV needed vs. the amount of CPU time it actually received. The number should be as close to 100 percent as possible. Then again, a CPU Effectiveness value of 20 percent could also be considered acceptable if the performance is acceptable service level agreements are being achieved.
The value is derived as follows:
When the IDMS system is dispatched by the operating system, one of the very first things done is to issue a STCK instruction. This represents the time IDMS was dispatched. When IDMS has finished all its processing, another STCK instruction is issued. This gives IDMS the ending time. The difference between the two is the amount of time the IDMS system was dispatched.
Between the two STCKs above, the IDMS system is calculating the amount of CPU time it is actually using operating system related timing functions. While the IDMS system is up and dispatched, it can be interrupted due to paging, swapping, or higher priority work. If such an interruption occurs, the CPUTIME used during this interrupt is not attributed to IDMS.
Example:
Assume the IDMS system is dispatched at STCK time 0 and goes to sleep at STCK time 10. During these 10 seconds, another application running at a higher priority is dispatched. Because this other application is running at a higher priority, the CPU is taken from the IDMS system. This other application runs for three seconds, then gives up control. The IDMS system which had been interrupted is then allowed to continue.
IDMS was dispatched for 10 seconds. Higher priority work interrupted for three seconds. The CPU effectiveness is 70 percent.
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