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IJ25390: SLOW TCP PERFORMANCE WITH VIRTUAL ETHERNET ADAPTER AND LARGESENDAPPLIES TO AIX 7200-04

A fix is available

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You can track all active APARs for this component.

 

APAR status

  • Closed as program error.

Error description

  • **************************************************************
    * USERS AFFECTED:
    * Systems running the AIX 7200-04-02-2015 or
    * 7200-04-02-2016 Technology Level or
    * VIOS 3.1.1.20 or 3.1.1.21 with
    * devices.vdevice.IBM.l-lan.rte below the
    * 7.2.4.3 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 IJ25390.
    * Prior to fix availability, an interim fix is available from
    * either
    * ftp://aix.software.ibm.com/aix/ifixes/ij25390/
    * https://aix.software.ibm.com/aix/ifixes/ij25390/
    * The ifix can be installed using Live Update (LU).
    * If LU is not used, 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

    IJ25390

  • Reported component name

    AIX V7.2

  • Reported component ID

    5765CD200

  • Reported release

    720

  • Status

    CLOSED PER

  • PE

    YesPE

  • HIPER

    YesHIPER

  • Submitted date

    2020-06-04

  • Closed date

    2020-06-04

  • Last modified date

    2020-07-31

Fix information

  • Fixed component name

    AIX V7.2

  • Fixed component ID

    5765CD200

Applicable component levels

  • R720 PSY U885349

       UP20/07/10 I 1000 Ž

PTF to Fileset Mapping

[{"Business Unit":{"code":"BU009","label":"Systems - Cognitive"},"Product":{"code":"SSVEF8"},"Platform":[{"code":"PF053","label":"Power Systems"}],"Version":"720"}]

Document Information

Modified date:
01 August 2020