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IJ25442: SLOW TCP PERFORMANCE WITH VIRTUAL ETHERNET ADAPTER AND LARGESENDAPPLIES TO AIX 6100-09

 

APAR status

  • Closed as program error.

Error description

  • **************************************************************
* USERS AFFECTED:
* Systems running VIOS 2.2.6.60 or 2.2.6.61
* with devices.vdevice.IBM.l-lan.rte at the
* 6.1.9.402 level.
  **************************************************************
* ERROR DESCRIPTION:
* The Virtual Ethernet Adapter can cause a significant
* degradation in TCP performance for largesend packets.
*
* This issue can be seen with VIOS (serving any AIX, IBMi, or
* Linux client LPAR) running the affected VIOS levels below.
* It can also be seen with any AIX client LPAR running the
* affected AIX levels below (regardless of the VIOS level).
* This issue only occurs when the client LPARS are configured
* for largesend traffic or VIOS is configured for largereceive
* traffic.
  **************************************************************
* RECOMMENDATION:
* Install APAR IJ25442.
* Prior to fix availability, an interim fix is available from
* either
* ftp://aix.software.ibm.com/aix/ifixes/ij25442/
* https://aix.software.ibm.com/aix/ifixes/ij25442/
* Installation of the ifix requires a reboot.
  **************************************************************

Local fix

  • Disable PLSO:

Either disable mtu_bypass:
# chdev -l enX -a mtu_bypass=off

or disable PLSO on the VEA or trunk VEA:
# chdev -l entX -a platform_lso=no

Problem summary

  • Customer may experience very slow TCP performance when Platform
Large Send is enabled on the network interface and the traffic
is VLAN tagged.

Problem conclusion

  • Fix ethernet header length calculation for VLAN tagged case.

Temporary fix

  •   *********
  * HIPER *
  *********

Comments

  • 6100-09 - use AIX APAR IJ25442
7100-05 - use AIX APAR IJ25443
7200-04 - use AIX APAR IJ25390

APAR Information

  • APAR number

    IJ25442

  • Reported component name

    AIX 6.1 EXT SUP

  • Reported component ID

    5765G6299

  • Reported release

    61E

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Submitted date

    2020-06-08

  • Closed date

    2020-06-08

  • Last modified date

    2020-11-16

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

    IJ25390

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

Fix information

  • Fixed component name

    AIX 6.1 EXT SUP

  • Fixed component ID

    5765G6299

Applicable component levels

[{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSLLZP","label":"AIX Standard Edition"},"Platform":[{"code":"PF053","label":"Power Systems"}],"Version":"61E","Line of Business":{"code":"LOB08","label":"Cognitive Systems"}}]

Document Information

Modified date:
18 November 2020

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