AIX 下光纤卡num_cmd_elems参数是有什么作用的呢，谢谢！

Fibre Channel device driver attributes

The fcs devices include specific attributes that can be changed on Virtual I/O

Servers. These attributes are num_cmd_elems and max_xfer_size. As a best

practice, complete a performance analysis on the adapters and change these

values, if needed. This analysis can be done with tools such as the fcstat

command as shown in Example 5-3 on page 69.

num_cmd_elems Modifies the number of commands that can be queued to the

adapter. Increasing num_cmd_elems decreases the No

Command Resource Count. Increasing num_cmd_elems also

makes it more likely to see No Adapter Elements Count, or

No DMA Resource Count increasing.

max_xfer_size Has an effect on the direct memory access (DMA) region

size that is used by the adapter. Default max_xfer_size

(0x100000) gives a small DMA region size. Tuning up

max_xfer_size to 0x200000 provides a medium or large

DMA region size, depending on the adapter.