A fix is available
APAR status
Closed as program error.
Error description
AIX LPARs using VLAN pseudo-devices configured over virtual ethernet ports, and observing bad performance when PLSO is enabled. Bug is in the virtual ethernet device driver receive path. When VLAN-tagged large packets send using PLSO are received by the driver, an incorrect ethernet header size is calculated which causes the driver to discard valid large receive packets.
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
Comments
APAR Information
APAR number
IJ25419
Reported component name
AIX V7.2
Reported component ID
5765CD200
Reported release
720
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Submitted date
2020-06-05
Closed date
2020-06-05
Last modified date
2020-11-16
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
AIX V7.2
Fixed component ID
5765CD200
Applicable component levels
R720 PSY U884097
UP20/11/04 I 1000
PTF to Fileset Mapping
U884097 devices.vdevice.IBM.l-lan.rte 7.2.5.0
[{"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSVEF8","label":"AIX 7.2 Enterprise Edition"},"Platform":[{"code":"PF053","label":"Power Systems"}],"Version":"720","Line of Business":{"code":"LOB08","label":"Cognitive Systems"}}]
Document Information
Modified date:
18 November 2020