Re: PgSp and Paging Space

From: Lamar Saxon (Lamar.Saxon_at_AMERICREDIT.COM)
Date: 11/09/05

  • Next message: Craig Otway: "Lawson"
    Date:         Wed, 9 Nov 2005 15:13:50 -0600
    To: aix-l@Princeton.EDU
    
    

    My guess...

    I think your binary was compiled with a maxDATA of 0x40000000. You can
    check this by doing a:

    dump -ohv <binary> and looking for the maxDATA field. Each of those
    represent a memory segment of 256M. So your process dies @ 1024 M.

    The APAR information you posted shows an override of the maxDATA field
    with the LDR_CNTRL environmental variable, common use in Java
    development. You made the max data segment 7 256M segments or 1792M...

    What you can try to do is change the LDR_CNTRL variable to a higher
    amount. Are you AIX 5.2 or greater ? Then try:

    export LDR_CNTRL=PREREAD_SHLIB@MAXDATA=0xA0000000@DSA

    This will allow you to use the Large Address Space model and have 11
    user segments for application.

    Also, what is the ulimit for data for the user.

    HTH,
    Lamar

    BTW, Hola' Tina !


      _____

    From: IBM AIX Discussion List [mailto:aix-l@Princeton.EDU] On Behalf Of
    SUBSCRIBE aix-l Tina N
    Sent: Wednesday, November 09, 2005 2:44 PM
    To: aix-l@Princeton.EDU
    Subject: Re: PgSp and Paging Space

    Hi Christopher...

    Well... I will take a stab at this...

    On the -P (ps) out from topas, the Paging Space column shows the amount
    of memory that one process is using.. you should have a list of several
    processes... I 'think' that is listed in 4K pages.
    On the -W page, the paging statistics of Used and Free should be similar
    to what you would see in lsps -s.

    My thought is that maybe a vmtune parm has limited the total amount of
    memory that could be used for one process. But, if you run out of
    paging..you should have an error in the errpt indicating so... is there
    one?

    One other thought.. does the process do an forking? You could try
    increasing the maximum number of processes used per user..
    I think the command is a chdev on sys0... however, to be sure...go into
    smit syschg.. max number of processes per user and increase it.

    I will keep thinking...

    Tina

    cbaker@GOODYEAR.COM
    Sent by: IBM AIX Discussion List <aix-l@Princeton.EDU>

    11/09/2005 03:06 PM
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    Re: PgSp and Paging Space


    Tina,

    Thanks for the white paper on memory leaks.

    Let me tell you more about this error.

    The user is running as root. The program is CATIA v5, function is IGES
    translator. The OS is AIX 5.2 ML05

    He looked on the web for possible error and found a similar error in an
    APAR on the IBM site. It had a work around of making the following
    declaration before starting the IGES translation:

           export LDR_CNTRL=PREREAD_SHLIB@MAXDATA=0x70000000
           export EXTSHM=ON
           export JIMSHMATNUM=0

    Now the IGES process runs until topas shows 1792 in the PgSp column,
    then it dies.

    Here are some of the error in the different log files:

    1) In the "/CATReport/wide1.err" we see:

           <E> [9502] Memory Check is NOK : Low memory situation --> partial
    transfer processing.
           Low memory status file is partially transferred. Please increase
    your memory space.

    2) In the window that IGES was started from, we see these errors:

           XMLMode !!! </tmp//BatchParameters_11.39.02.xml>
          Local : <1>

            Warning : detected a low virtual memory condition

          Please close some applications
           +=============================================+
           ! An unhandled exception occurred in CATIA V5 !
           +=============================================+
          Terminating ...
          2 CATMfPartExtMLK stay in memory

    I still do not understand why "lsps -a" shows no SWAP failing. The
    memory data in "topas" does not imply either real or virtual memory is
    running out. So what is the "PgSp" column that shows 1179 now???

    Thanks,

    Christopher M. Baker
    Senior Technical Support Analyst
    DSE/TCO
    Goodyear Tire and Rubber Company

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    SUBSCRIBE aix-l Tina N <christina_lewis@NEXNET.NAVY.MIL>
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    Subject Re: PgSp and Paging Space


    maybe take a look at some of the vmtune parms.. maybe that will help.
    Also..I have this doc on memory leaks i have attached... it may have
    some useful tips in it...

    cbaker@GOODYEAR.COM
    Sent by: IBM AIX Discussion List <aix-l@Princeton.EDU>

    11/09/2005 01:25 PM

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    IBM AIX Discussion List <aix-l@Princeton.EDU>

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    Subject PgSp and Paging Space


    Folks,

    I have an admin here who is trying to run a fairly simple command on
    AIX, but after a while, he gets an Out of Virtual Memory error and it
    dies.

    I changed all the ulimits to -1, that did not help.

    I had him run the command while I monitored the system with "topas".
    There I see that Paging Space never moves from 99% Free, but in the
    process (ps) section of topas, I see that his running process uses 25%
    of the 4-CPU server and, in the next column, labeled "PgSp", the number
    keeps on growing. When it gets nearly to 1024, the process dies.

    So, what is the difference between the Paging Space, ( same thing one
    gets from "lsps -a") that never grows and the "PgSp" in the processes
    section of "topas" that shows it is growing?

    This box is a P655 with 4 GB of real memory and 2 GB of swap.

    Thanks,

    Christopher M. Baker
    Senior Technical Support Analyst
    DSE/TCO
    Goodyear Tire and Rubber Company

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  • Next message: Craig Otway: "Lawson"

    Relevant Pages

    • Re: PgSp and Paging Space
      ... memory that could be used for one process. ... Re: PgSp and Paging Space ... Now the IGES process runs until topas shows 1792 in the PgSp column, ...
      (AIX-L)
    • Re: PgSp and Paging Space
      ... Thanks for the white paper on memory leaks. ... Now the IGES process runs until topas shows 1792 in the PgSp column, ... So what is the "PgSp" column that shows 1179 now??? ... Re: PgSp and Paging Space ...
      (AIX-L)
    • Re: PgSp and Paging Space
      ... represent a memory segment of 256M. ... Are you AIX 5.2 or greater? ... Subject: PgSp and Paging Space ...
      (AIX-L)
    • Re: Paging space on a fastT
      ... Concerning adding additional paging space to external disks, ... Depending on the version of AIX ... virtual memory in order to free up segments for other processes. ... that allocates virtual memory and real memory. ...
      (AIX-L)
    • Re: paging space
      ... I would suggest to check the official performance management guide, since it describes pretty well how memory management works in AIX. ... Considering the kernel part of your question, as far as I can remember this is not the way how it works. ... Early paging space allocation algorithm can also twist the situation a bit. ...
      (AIX-L)

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