A fix is available
APAR status
Closed as program error.
Error description
There is a spike in CSM fixed 32K dataspace buffers filled with IUDR packing buffers that contains packets already sent outbound and are waiting to be released or reused until the timer expires. The packing buffers should be freed sooner. This spike could cause CSM fixed storage to become constrained. . KEYWORDS: IUDR blocking factor group . VERIFICATION STEPS: There is not data on the tcp or ucb send queues. . The 32K CSM dataspace buffers are fixed and contain IUDRs with SPACs in them. The SPACs are on the TSEB_QDIO_BGRP_Q@
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of the IBM Communications Server * * for z/OS Version 1 Release(s) 10, 11, and * * 12 IP * **************************************************************** * PROBLEM DESCRIPTION: TCP/IP is not responsive to CSM FIXED * * constrained or critical state when * * releasing Blocking Groups (BGRP) and * * associated packing buffers. * **************************************************************** * RECOMMENDATION: * **************************************************************** TCP/IP is not responsive to CSM FIXED constrained or critical state when releasing Blocking Groups (BGRP) and associated packing buffers. BGRPs are used to improve the efficiency of passing outbound packets to the device layer (DLC). BGRPs and their associated packing buffers are allocated in CSM Dataspace and must be page fixed for the DLC. When a BGRP has been processed by the DLC it is placed on a cache queue. The BGRP cache queue is scanned periodically and old BGRPs are released. The BGRP cache scan logic does not take into account the state of CSM. This can lead to a CSM FIXED constrained or critical state persisting longer than necessary when large numbers of BGRPs are cached. +-------------------------------------------------------------+ + Please check our Communications Server for OS/390 homepages + + for common networking tips and fixes. The URL for these + + homepages can be found in Informational APAR II11334. + +-------------------------------------------------------------+
Problem conclusion
EZBIFOB1 has been amended to take the CSM FIXED state into account during BGRP cache scans. BGRPs and associated packing buffers will be aggressively released when CSM is in a FIXED constrained or critical state. * Cross Reference between External and Internal Names
Temporary fix
Comments
APAR Information
APAR number
PM31494
Reported component name
TCP/IP V3 MVS
Reported component ID
5655HAL00
Reported release
1A0
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2011-01-28
Closed date
2011-03-04
Last modified date
2011-04-04
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK65650 UK65651 UK65652
Modules/Macros
EZBIFBP1
Fix information
Fixed component name
TCP/IP V3 MVS
Fixed component ID
5655HAL00
Applicable component levels
R1A0 PSY UK65650
UP11/03/26 P F103
R1B0 PSY UK65651
UP11/03/26 P F103
R1C0 PSY UK65652
UP11/03/26 P F103
Fix is available
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Document Information
Modified date:
04 April 2011