如题,参数的作用是:controls maximum number of in-flight Ios 怎么解释这个含义?
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.
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