Thanks a lot, Barry. I read this part of note in MXG sourcelib,too. It is very useful.
However, I'm a little bit confuced when I sum up CPITCBTM & CPISRBTM by date for the 2 lpars (one is DDCONS=YES, the other is NO), the result is not what I expected to see: 1. The lpar with DDCONS=NO, then total CPITCBTM+CPISRBTM approachs 0. because all the jobs should bypass DD consolidations. But what I got is, still many many jobs spend a few seconds on CPITCBTM. So, how to explain? 2. The lpar with DDCONS=YES, should have much bigger value for CPITCBTM+CPISRBTM than the other lpar. But in fact the difference varies from 100 seconds to 350 seconds per day. regarding the EMPTYEXCPSEC(SUPPRESS) , we're still in 1.9. On Mon, Dec 21, 2009 at 5:40 AM, Barry Merrill <ba...@mxg.com> wrote: > In 1987, Diane Eppestine at Southwestern Bell saw that whenever their > SAR job (a SYSOUT processing subsystem) was cancelled, the CPU went to > 100% busy for 30-60 minutes. Instruction traces found the "loop" was in > DD Consolidation. SAR dynamically allocates a DD for each SYSOUT file > it processes; by the end of the week that step had over 75,000 DD > entries! DD consolidation reads the first DD segment, scans the > remaining 74,999 segments for a match, reads the second and scans the > remaining 74,998 for a match, etc. etc., etc., all at DPRTY=FE! In > response to Diane's discovery, Bill Richardson, IBM SMF Development, > subsequently provided a new SMF option, DDCONS(NO), specified in > SYS1.PARMLIB(SMFPRMxx), so that you can disable this very unwise (in my > opinion) algorithm, and thereby eliminate its wasted CPITCBTM and CPISRBTM > (MXG names for SMF30ICU and SMF30ISB, the "Initiator" CPU time that > occurs before Step Program Load and after Step Program Termination). > > All of those empty SYSOUT DD segments can now be removed in z/OS 1.10 > with the EMPTYEXCPSEC(SUPPRESS) option: > > > > 1. APAR Identifier OA29582 adds new EMPTYEXCPSEC(SUPPRESS) option in > SYS1.PARMLIB to suppress all empty EXCP entries. > > The option prevents the creation of null segments in SMF 30 records > for SMS Candidate Volumes, and could significantly reduce the size > of your step and job termination records, especially if your site > has a default of (SYSDA,5) for every allocation!! > > The MVS Initialization and Tuning Reference, under the SMFPRMxx > parmlib parameter definitions, EMPTYEXCPSEC: > SUPRESS specifies that the system suppress the creation of empty > EXCP sections. Empty sections can be the result of non-dataset > allocations, such as DD DUMMY, or for spool file allocations > (i.e., SYSIN, SYSOUT JES DDs), or for non-allocated candidate > volumes in the SMS storage group. > > One MICS site reported a 28% reduction in CPU time with removal of > all of their empty EXCP segments. > > New EMPTYEXCPSEC option in PARMLIB is z/OS 1.10 only. > While EMPTYEXCPSEC option is documented in the z/OS 1.9 SMF > manual in Section 13.34.2.7 (Execute Channel Program (EXCP) > Section) of z/OS MVS System Management Facilities (SMF) Document > SA22-7630-16, for z/OS 1.9, testing on a z/OS 1.9 system > resulted in > > IEE945I UNRECOGNIZABLE OPTION 'EMPTYEXCPSEC' IN PARMLIB INPUT > IEE947I '/* DEFAULT RETRY */ > EMPTYEXCPSEC(SUPPRESS)' SKIPPED DUE TO PREVIOUS ERROR > > IBM has confirmed that the option only exists in z/OS 1.10, where > it is listed in the Release Guide as a 1.10 enhancement > > > > Barry Merrill > > ---------------------------------------------------------------------- > For IBM-MAIN subscribe / signoff / archive access instructions, > send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO > Search the archives at http://bama.ua.edu/archives/ibm-main.html > -- Cobe Xu Best Regards ----------------------------------------------------------- zOS Performance & Capacity Analyst E2E Performance Analyst Email: cob...@gmail.com ----------------------------------------------------------- ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to lists...@bama.ua.edu with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html