Peter Worth a try ?
Peter Giles Systems Programmer ITSG DEEWR C14BR2 Level 2, 14 Brindabella Cct, Pialligo ACT 2609 Tel +61 2 6121 8081 Fax +61 2 6276 4908 Mob 0411 074 964 [email protected] -----Original Message----- From: IBM Mainframe Discussion List [mailto:[email protected]] On Behalf Of Barry Merrill Sent: Monday, December 21, 2009 8:41 AM To: [email protected] Subject: Re: SMF30 record length 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 [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html Notice: The information contained in this email message and any attached files may be confidential information, and may also be the subject of legal professional privilege. If you are not the intended recipient any use, disclosure or copying of this email is unauthorised. If you received this email in error, please notify the DEEWR Service Desk by calling (02) 6240 9999 and delete all copies of this transmission together with any attachments. ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: GET IBM-MAIN INFO Search the archives at http://bama.ua.edu/archives/ibm-main.html
