PJ40485: MANY ECB'S CAN QUEUE TO INACCESABLE SOCKET

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APAR status

  • Closed as program error.

Error description

  • See Problem Summary.
    

Local fix

  • na
    

Problem summary

  • APAR NUMBER:  PJ40485
    PRODUCT:  z/TPF
    FUNCTIONAL AREA:  TCP/IP NATIVE STACK
    SHIPPED IN PUT:  10
    
    ABSTRACT:
    Socket monitoring of seckets with ECBs queued to send.
    
    PACKAGE CONTENTS:
    Source Segments:
    (C) base/cp/ctsm.cpy
    (C) base/include/tpf/iusmo.h
    (C) base/include/tpf/i_pwbl.h
    (C) base/macro/ipwbl.mac
    (C) base/macro/isock.mac
    (C) base/macro/iusmo.mac
    (C) base/rt/cmvp.asm
    (C) base/rt/ctfe.asm
    (C) base/rt/cts8.asm
    (C) base/rt/usmo.c
    
    Object Only Binaries:
    None.
    
    Configuration Independent Binaries:
    (C) base/load/CMVP.so
    (C) base/load/CTFE.so
    (C) base/load/CTS8.so
    (C) base/obj/cmvp.o
    (C) base/obj/ctfe.o
    (C) base/obj/cts8.o
    
    Support Files:
    base/lst/cmvp.lst
    base/lst/ctfe.lst
    base/lst/cts8.lst
    base/lst/CMVP.map
    base/lst/CTFE.map
    base/lst/CTS8.map
    
    OTHER BINARIES TO BUILD: YES
    (C) <sys>/load/CPS0.so
    (C) <sys>/load/USMO.so
    (C) <sys>/obj/cctcp3.o
    (C) <sys>/obj/usmo.o
    (C) os390/bin/ppcp.pds
    (C) os390/obj/stpp.o
    
    COMMENTS:
    ECBs queued up to send on a socket can deplete system resources
    to critically low levels. Socket monitoring for high ECB queue
    counts on sockets will allow the customer to use the USMO user
    exit to handle these conditions.
    

Problem conclusion

  • SOLUTION:
    This enhancement allows the socket monitor to keep track of the
    number of ECBs that issued a send type API (send(), sendto(),
    write(), and writev()) for a given socket and are queued up
    (suspended) because that socket is blocked. If the number of
    queued ECBs for a given socket reaches certain thresholds
    (threshold values are 10, 25, 50, and 100), the existing socket
    monitor user exit, USMO, will be activated. This allows the
    customer to determine what action to take for the socket (such
    as closing the socket, which would cause all the queued ECBs
    for that socket to be posted so they can go away). Similar to
    other conditions the socket monitor detects, the user exit will
    be called at most once per minute per socket for each threshold
    reached. The user exit is called immediately when the threshold
    is reached. For example, the instant that an 11th ECB becomes
    queued waiting to send on a socket, the user exit will be
    called at the point in time (does not wait for a minute
    boundary to call the exit). Input to the user exit will include
    the condition (send ECBs threshold exceeded), the IP addresses
    and ports of the socket, the file descriptor for the socket,
    and the threshold level just exceeded for this socket. The
    default logic in the user exit is to do nothing.
    
    In addition, the output of the SOCK0043I message, which is the
    normal reply for the 'ZSOCK DISPLAY FORMAT SOCK-xxxxxx'
    command, has been modified with the following additional
    information: the real address of the socket block in memory and
    the current send threshold value along with the current send
    threshold length. A threshold value of 32767 indicates that the
    maximum threshold length of 100 has been exceeded.
    
    COREQS: NO
    None.
    
    MIGRATION CONSIDERATIONS: YES
    Functional, automation, and operation changes:
    SOCK0043I
    
    User exit changes:
    The USMO socket monitor user exit now has another defined
    condition to indicate that one of the send(), sendto(),
    write(), or writev() ECB queue length thresholds has been
    exceeded.  Input to the user exit will include the condition
    (send ECBs threshold exceeded), the IP addresses and ports of
    the socket, the file descriptor of
    the socket, and the threshold value that was just exceeded on
    sends for this socket.  ZNKEY SOCKMON-YES must be entered to
    activate socket monitoring if users would like to have the
    socket monitor user exit called for this condition or any of
    the other previously defined conditions.
    
    
    
    BUILD COMMANDS AND INSTRUCTIONS: YES
    #maketpf commands for linux
    maketpf -f CPS0 cctcp3.o
    maketpf -f USMO usmo.o
    maketpf -f CTS8 cts8.o
    maketpf -f CTFE ctfe.o
    maketpf -f CMVP cmvp.o
    maketpf CPS0 link
    maketpf USMO link TPF_VERIFY_LINK_REFS=NO
    maketpf CTS8 link
    maketpf CTFE link
    maketpf CMVP link
    maketpf USMO link
    #maketpf commands for z/OS
    maketpf -f ppcp stpp.o
    maketpf ppcp link
    
    UPDATED INFORMATION UNITS: YES
    z/TPF Operations
    z/TPF TCP/IP
    
    See your IBM representative if you need additional information.
    
    DOWNLOAD INSTRUCTIONS:
    http://www.ibm.com/software/htp/tpf/maint/maintztpf.html
    
    APAR URL:
    http://www.ibm.com/software/htp/tpf/ztpfmaint/put10/PJ40485.htm
    

Temporary fix

Comments

APAR Information

  • APAR number

    PJ40485

  • Reported component name

    Z/TPF

  • Reported component ID

    5748T1501

  • Reported release

    110

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-08-20

  • Closed date

    2012-12-07

  • Last modified date

    2012-12-07

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Publications Referenced
SK2T8062        

Fix information

  • Fixed component name

    Z/TPF

  • Fixed component ID

    5748T1501

Applicable component levels

  • R110 PSY

       UP



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Document information


More support for:

TPF
z/TPF

Software version:

110

Reference #:

PJ40485

Modified date:

2012-12-07

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