IBM Support

IV51157: NCARGS ALLOCATED FROM HEAP 0 APPLIES TO AIX 6100-09

A fix is available

Subscribe

You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • On a system with a very heavy exec workload, we can drive
    very sevear contention on heap 0 xmalloc lock. This is
    because ncargs by defaul allocates 1MB from the heap
    which exceeds the nh_balance threshold which by default
    is 64K. NCARGS should be allocated from the srad heaps
    as it is a very frequent allocation and it is better to
    make a change to directly call xmlloc_srad() when we
    allocate the space for ncargs rather than change the
    system global threshold as most other allocations of
    this size tends to be static.
    

Local fix

  • There are two possible work arounds:
    Reduce ncargs : chdev -l sys0 -a ncargs=16
    Increase nh_balance : errctrl nh_balance=2097152 -c alloc
    

Problem summary

  • On a system with a very heavy exec workload and large number
    of CPU's, we can drive severe contention on xmalloc lock
    called in exec path, causing system to get slowdown.
    

Problem conclusion

  • Allocate memory from the respective SRAD's for ncargs.
    

Temporary fix

Comments

  • 6100-07 - use AIX APAR IV52681
    6100-08 - use AIX APAR IV53167
    6100-09 - use AIX APAR IV51157
    6100-09 - use AIX APAR IV51157
    6100-09 - use AIX APAR IV51157
    7100-01 - use AIX APAR IV50813
    7100-02 - use AIX APAR IV50347
    7100-03 - use AIX APAR IV51322
    

APAR Information

  • APAR number

    IV51157

  • Reported component name

    AIX 610 STD EDI

  • Reported component ID

    5765G6200

  • Reported release

    610

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Submitted date

    2013-10-21

  • Closed date

    2013-10-21

  • Last modified date

    2014-08-14

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

    IV50347

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

    IV52681 IV53167

Fix information

  • Fixed component name

    AIX 610 STD EDI

  • Fixed component ID

    5765G6200

Applicable component levels

  • R610 PSY U859304

       UP14/05/21 I 1000

PTF to Fileset Mapping



Document information

More support for: AIX Enterprise Edition

Software version: 610

Operating system(s): AIX

Reference #: IV51157

Modified date: 14 August 2014