A fix is available
APAR status
Closed as program error.
Error description
You are running a stress workload to cross instance applications with RTIMOUT and MONITOR timeouts set to purge transactions that take excessive time to complete. When one region is slowed, the processing is affected on the other regions, as multiple tasks are delayed and eventually purged. . Investigation of dumps reveal that much time is spent by tasks waiting for the exclusive lock for an INQUIRE call for DFHSOTB. The information sought from the INQUIRE is the port number of the TCPIPSERVICE. This information is static, and could be obtained and saved during CAPEX processing, avoiding the lock entirely at this juncture. KIXREVEAA
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All CICS users. * **************************************************************** * PROBLEM DESCRIPTION: CICS region slowdown after a large * * number of IPIC DPL requests are * * received. * **************************************************************** * RECOMMENDATION: * **************************************************************** A large number of IPIC DPL requests are received in CICS. Mirror tasks are attached in the remote region to handle them. When each mirror task starts, DFHISXM runs for init and bind. During bind, a monitoring performance record is captured. This record requires the TCPIPSERVICE name and port number. The port number is not held by IS domain so a DFHSOTB INQUIRE_TCPIPSERVICE call is made. DFHSOTB acquires the TCPIPSERVICE lock exclusively, and then gathers the information required to satisfy the inquire (by calling DFHSOTD). This does not check which fields were requested so does a lot of processing, including switching to the SO TCB as part of inquire_connection. While on the SO TCB the next mirror task can start on QR. It reaches DFHSOTB and then suspends waiting for the lock. In a busy system many mirror tasks can end up waiting. The first mirror task returns to QR and releases the lock. The other mirror tasks all resume and retry the lock acquire. This causes excessive processing as tasks suspend and resume. Due to the nondeterministic nature of lock acquire, some tasks may time out after multiple attempts to acquire the lock.
Problem conclusion
Copybook DFHISDCC is changed to add field iscb_tcpips_port to the ISCB (IPCONN) control block. Module DFHISXM is changed to store the TCPIPSERVICE port number in iscb_tcpips_port for the applicable ISCB. Program DFHISCOP is changed to clear iscb_tcpips_port in the ISCB when the associated IPCONN is released.
Temporary fix
FIX AVAILABLE BY PTF ONLY
Comments
APAR Information
APAR number
PM88910
Reported component name
CICS TS Z/OS V5
Reported component ID
5655Y0400
Reported release
800
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2013-05-13
Closed date
2013-05-23
Last modified date
2015-03-04
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK94611
Modules/Macros
DFHCIS4 DFHISAL DFHISCOP DFHISCO DFHISCU DFHISDM DFHISDUF DFHISEMP DFHISEM DFHISFS DFHISIC DFHISIF DFHISIS DFHISJU DFHISLQP DFHISLQ DFHISPHP DFHISPH DFHISPRP DFHISRE DFHISRRP DFHISRR DFHISRSP DFHISRS DFHISSR DFHISST DFHISTRI DFHISUE DFHISXF DFHISXM DFHISXS DFHISZA DFHMIRS
Fix information
Fixed component name
CICS TS Z/OS V5
Fixed component ID
5655Y0400
Applicable component levels
R800 PSY UK94611
UP13/06/01 P F305
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.
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Document Information
Modified date:
04 March 2015