A fix is available
APAR status
Closed as program error.
Error description
A customer experienced significant performance impact after setting a SLIP similar to the following: SLIP SET,IF,PVTMOD=(XYZ,100),MODE=HOME,END Use of MODE=HOME with neither JOBNAME nor ASID specified can cause significant overhead, even if the SLIP is enabled but inactive (meaning the PVTMOD has not been loaded onto the system yet). To monitor for MODE=HOME, SLIP processing activates cross memory/space switching hooks. In the case of the above SLIP coded with MODE=HOME and with neither JOBNAME nor ASID specified, these hooks apply to every address space on the system rather than selectively to just one or two address spaces, resulting in the noted performance impact. Note that the SLIP PRCNTLIM parameter offers protection only if PER interrupts are occurring. VERIFICATION STEPS: 0) This assumes a system experiencing a performance problem. 1) Use console command D SLIP to list SLIPs defined to system, and use D SLIP=xxxx to list specific SLIP traps. Look for a PER trap that is ENABLED and has MODE=HOME specified, but has neither JOBNAME nor ASID specified. 2) Verify that disabling the SLIP trap eliminates the performance problem: SLIP MOD,DISABLE,ID=xxxx
Local fix
Disable the PER trap using the following command: SLIP MOD,DISABLE,ID=xxxx
Problem summary
**************************************************************** * USERS AFFECTED: Users at HBB7790 using SLIP. * **************************************************************** * PROBLEM DESCRIPTION: Significant performance impact after * * setting SLIP with MODE=HOME and without * * JOBNAME and ASID. * **************************************************************** * RECOMMENDATION: * **************************************************************** Significant performance impact occurred after setting s SLIP with MODE=HOME specified without JOBNAME and ASID.
Problem conclusion
A new trap IeaSlipConfirm is created for DIAGxx. When IeaSlipConfirm is specified in DIAGxx, SLIP is to check if JOBNAME or ASID is specified when MODE=HOME is specified in the SLIP command. If both JOBNAME and ASID parameters were omitted, SLIP is to issue message IEE088D to prompt for reply to continue or cancel the command. Documentation for APAR OA45297 The following publication will be updated as follows to add the new information in the indicated existing topic- SA23-1380-00 z/OS V2R1.0 MVS Initialization and Tuning Reference Topic: Chapter 31. DIAGxx (control common storage tracking and GFS trace) Subtopic: Statements/parameters for DIAGxx under section TRAPS NAME ( trapname1,{trapname2}... ) add following new trap: IeaSlipConfirm SLIP is to check if JOBNAME or ASID is specified when MODE=HOME is specified in the SLIP command. If both JOBNAME and ASID parameters were omitted, SLIP is to issue message IEE088D to prompt for reply to continue or cancel the command. In the future it is possible that this trap would apply to additional SLIP operand checking confirmation. SA38-0674-00 z/OS V2R1.0 MVS System Messages, Vol 7 (IEB-IEE) Topic: Chapter 4. IEE messages add following new message: IEE088D SLIP COMMAND SPECIFIES MODE=HOME WITHOUT JOBNAME AND ASID. SPECIFY 'OK' OR 'CANCEL' - or - IEE088D SLIP ID=xxxx SPECIFIES MODE=HOME WITHOUT JOBNAME AND ASID. SPECIFY 'OK' OR 'CANCEL' Explanation: A SLIP command was issued with MODE=HOME specified, but the JOBNAME and ASID parameters were omitted. The omission of these parameters may cause significant performance impact. Refer to the "Setting Effective SLIP PER Traps" section in the SLIP Command in the z/OS System Command book. The SLIP trap could have been set with the OK operand to avoid getting the message. In the message text: xxxx The ID of the trap being set. System action: SLIP command processor waits for a response. If the response is 'OK', the trap will be set. If the response is 'CANCEL', the command will be cancelled. Operator response: One of the following: . If you want to set the trap as is, reply 'OK'. . If you want to avoid setting the trap, reply 'CANCEL'. You may then reissue the command with JOBNAME/ASID or without MODE=HOME. Source: SLIP Module: IEECB909 Routing code: * Descriptor code: 5 The following publication will be updated as follows to add the flagged information in the indicated existing topic- SA38-0666-00 z/OS V2R1.0 MVS System Commands Topic: SLIP Command Subtopic: Coding SLIP command parameters OK For a SLIP SET trap, omits checking that could result | in WTOR messages IEE604D, IEE831D, and IEE088D. IBM recommends that you use the OK parameter only when issuing SLIP from a parmlib member.
Temporary fix
Customers can prevent experiencing this performance issue altogether, for both active and inactive SLIP PER traps, by avoiding specification of MODE=HOME without also specifying either JOBNAME or ASID. In other words, when using MODE=HOME, use JOBNAME or ASID as well.
Comments
APAR Information
APAR number
OA45297
Reported component name
SLIP/PER
Reported component ID
5752SCSLP
Reported release
790
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2014-05-23
Closed date
2014-08-20
Last modified date
2014-10-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UA74641 UA74642
Modules/Macros
IEECB909 IEECB946 IEERTMEN IEERTMJP IGVDGNB IGVDGNTM
SA23138000 | SA38067400 | SA38066600 |
Fix information
Fixed component name
SLIP/PER
Fixed component ID
5752SCSLP
Applicable component levels
Fix is available
Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.
[{"Business Unit":{"code":"BU054","label":"Systems w\/TPS"},"Product":{"code":"SG19M","label":"APARs - z\/OS environment"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"790","Edition":"","Line of Business":{"code":"","label":""}},{"Business Unit":{"code":null,"label":null},"Product":{"code":"SG19O","label":"APARs - MVS environment"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"790","Edition":"","Line of Business":{"code":"","label":""}}]
Document Information
Modified date:
02 October 2014