On very rare occasions, some PCIe option cards that are capable of data transfer rates of 5.0 GT/s and above might fail to train at the maximum supported target speed. Instead, they train at the minimum speed of 2.5 GT/s, which might lead to poor I/O performance.
Workaround:
If you suspect poor I/O performance, use the prtdiag command to view PCIe card I/O performance.
The current link data rate for each slot is displayed under the Speed heading.
# prtdiag
System Configuration: Oracle Corporation sun4v
Memory size: 523008 Megabytes
...
================================= IO Devices =================================
Slot + Bus Name + Model Speed
------------------------------------------------------------------------------
Status Type Path
/SYS/MB/USB_CTLR PCIE usb-pciexclass,0c0330 5.0GTx1
/SYS/RCSA/PCIE4 PCIE SUNW,qlc-pciex1077,2532 QLE2562 5.0GTx4
/SYS/RIO/NET1 PCIE network-pciex8086,1528 5.0GTx8
/pci@300/pci@1/pci@0/pci@4/pci@0/pci@6/usb@0
/pci@440/pci@1/pci@0/pci@c/SUNW,qlc@0
/SYS/RCSA/PCIE10 PCIE SUNW,qlc-pciex1077,2532 QLE2562 5.0GTx4
/pci@480/pci@1/pci@0/pci@4/SUNW,qlc@0
/SYS/RCSA/PCIE10 PCIE SUNW,qlc-pciex1077,2532 QLE2562 5.0GTx4
/pci@480/pci@1/pci@0/pci@4/SUNW,qlc@0,1
/pci@300/pci@1/pci@0/pci@4/pci@0/pci@8/network@0,1
/SYS/RIO/NET0 PCIE network-pciex8086,1528 5.0GTx8
/SYS/RCSA/PCIE4 PCIE SUNW,qlc-pciex1077,2532 QLE2562 5.0GTx4
/SYS/RCSA/PCIE6 PCIE SUNW,qlc-pciex1077,2532 QLE2562 5.0GTx4
/pci@600/pci@1/pci@0/pci@8/SUNW,qlc@0
/SYS/RCSA/PCIE6 PCIE SUNW,qlc-pciex1077,2532 QLE2562 5.0GTx4
/pci@600/pci@1/pci@0/pci@8/SUNW,qlc@0,1
/SYS/RCSA/PCIE2 PCIE SUNW,qlc-pciex1077,2532 QLE2562 5.0GTx4
/pci@300/pci@1/pci@0/pci@4/pci@0/pci@8/network@0
/pci@440/pci@1/pci@0/pci@c/SUNW,qlc@0,1
/SYS/RCSA/PCIE8 PCIE SUNW,qlc-pciex1077,2532 QLE2562 5.0GTx4
/pci@640/pci@1/pci@0/pci@8/SUNW,qlc@0
/SYS/RCSA/PCIE8 PCIE SUNW,qlc-pciex1077,2532 QLE2562 5.0GTx4
/pci@640/pci@1/pci@0/pci@8/SUNW,qlc@0,1
/pci@400/pci@1/pci@0/pci@c/SUNW,qlc@0
/SYS/RIO/NET2 PCIE network-pciex8086,1528 5.0GTx8
/SYS/RCSA/PCIE2 PCIE SUNW,qlc-pciex1077,2532 QLE2562 5.0GTx4
/pci@6c0/pci@1/pci@0/pci@c/pci@0/pci@4/network@0
/pci@400/pci@1/pci@0/pci@c/SUNW,qlc@0,1
/SYS/RIO/USB_CTLR PCIE usb-pciexclass,0c0330 5.0GTx1
/SYS/RIO/NET3 PCIE network-pciex8086,1528 5.0GTx8
/pci@6c0/pci@1/pci@0/pci@c/pci@0/pci@6/usb@0
/pci@6c0/pci@1/pci@0/pci@c/pci@0/pci@4/network@0,1
/SYS/RIO/VIDEO PCIE display-pciex102b,522 2.5GTx1
/pci@6c0/pci@1/pci@0/pci@c/pci@0/pci@7/display@0
/SYS/MB/SASHBA1 PCIE scsi-pciex1000,87 LSI,2308_2 5.0GTx8
/pci@6c0/pci@1/pci@0/pci@c/pci@0/pci@c/scsi@0
Refer to the documentation for your specific option cards to determine their target transfer rate.
If a PCIe card does not match the maximum target speed supported by the system, then remove and reinstall the PCIe card using the hot-serviceable method, as described in the SPARC T5-4 Service Manual.