DMA Throughput

Throughput of your DMA must be at least 1.3GBps (note that the output is in Bytes, not bits):

 ethtool -S eth2 | fgrep dma

 read_dma_bw_MBs: 1757

 write_dma_bw_MBs: 1736

 read_write_dma_bw_MBs: 3436

MSI Interrupts

Check the MSI interrupts:

 lspci -vv | fgrep -A 50 Myri | egrep '(MSI)'

Look for the output

 Subsystem: MYRICOM Inc. 10G-PCIE-8A (MSI-X firmware)

 Capabilities: [44] MSI: Enable+ Count=1/1 Maskable- 64bit+

PCIE Utilization

The Myrinet card uses 8 lanes in PCIe. To check, whether the port it is connected to provides all 8, enter the command:

  lspci -vv | fgrep -A 50 Myri | egrep '(LnkCap|LnkSta)'

The output should look like this:

 LnkCap: Port #0, Speed 2.5GT/s, Width x8, ASPM L0s, Latency L0 unlimited, L1 unlimited

 LnkSta: Speed 2.5GT/s, Width x8, TrErr- Train- SlotClk- DLActive + BWMgmt- ABWMgmt-

Write-Combining

It is good idea to have the write-combining set, althrough for fast processors it is not a critical point

How to do so you can find at this page.

Additional

Try to fiddle with flow control (myri10ge_flow_control during load of module via modprobe), default is usually correct though (FC on).