A fix is available
APAR status
Closed as program error.
Error description
External symptoms: CPU monitors shows JES3 using excessively more CPU than normal, customer running with Netserv Impact to customer: system performance slow Analysis: An SVC dump taken at the time of the spike show the TCP and MSGC FCT's processing slowly, searching for matching selection criteria for the Netservs. The system has a large number of jobs in output service, each OSE is being searched. The algorithm used to search is inefficient. Verification steps: 1) JES3 CPU usage higher than normal 2) SVC dump of JES3 address space significant number of external interrupts in the system trace under module IATOSBM The projected closing code is PER for releases HJS7770 and up.
Local fix
Stop all Netservs except for one to reduce contention.
Problem summary
**************************************************************** * USERS AFFECTED: All users of HJS7770 and HJS7780. * **************************************************************** * PROBLEM DESCRIPTION: High CPU utilization by JES3 TCP/IP. * **************************************************************** * RECOMMENDATION: * **************************************************************** The customer noticed periods of high CPU utilizations lasting sometimes for several hours. Several dumps were taken during the problem period. A JMF was also run and the report was provided to IBM. The documentation analysis showed the Get routine in module IATOSBM taking a big percentage of the overall JES3 Nuc task CPU usage. The selection algorithm in that routine was such that it searched through all Resqueue (RQ - IATYRSQ) control blocks to find one with TCP/IP NJE (or BDT) output. But only a very small fraction of the RQs contained TCP/IP output. Moreover, due to competing TCP NJE FCTs (IATYFCT), the code kept re-scanning the chain.
Problem conclusion
Installation On (Global) Order (Any) Activation Order (Any) Type/JES3 restart (Hot) Type/IPL (None) CLPA (No) (See Apar II07968 for definitions) Code in the Get routine of module IATOSBM was changed to only search the TCP (or BDT) chain of OSE (IATYOSE) control blocks. That will significantly reduce the search code path and the CPU usage by the TCP FCT (IATYFCT). APAR OA40581 prereq's (and sup's) for FMID HJS7770: Pre's: * NONE * APAR OA40581 prereq's (and sup's) for FMID HJS7780: Pre's: * NONE *
Temporary fix
********* * HIPER * ********* *** * TEMPORARY FIX MAY BE OBTAINED FROM DLL OR INFO/ACCESS **** ******************* OA40581 DECK AVAILABLE ********************
Comments
APAR Information
APAR number
OA40581
Reported component name
JES3
Reported component ID
5752SC1BA
Reported release
780
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt
Submitted date
2012-10-12
Closed date
2012-12-12
Last modified date
2013-01-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UA67496 UA67497
Modules/Macros
IATOSBM
Fix information
Fixed component name
JES3
Fixed component ID
5752SC1BA
Applicable component levels
Fix is available
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Document Information
Modified date:
02 January 2013