DETERMINING A DIRECT MEMORY ACCESS DATA TRANSFER MODE

摘要

In response to receiving a request for a DMA data transfer, a DMA transfer mode may be determined based on based on the size of the requested DMA data transfer and profile data of an I/O adapter. The profile data for the I/O adapter may include a physical location of the I/O adapter or a number of clients supported by the I/O adapter. The DMA transfer mode may also be determined based on a preference of an application or an I/O device. Moreover, the DMA transfer mode may be determined based on a CPU usage metric being outside of a threshold for the CPU usage metric or on a memory usage metric being outside of a threshold for the memory usage metric.

主权项

1. A system for determining a direct memory access (DMA) data transfer mode, comprising:
a DMA unit to receive a request for a DMA data transfer and to perform the requested DMA transfer using a determined DMA transfer mode; and an I/O adapter to determine the DMA transfer mode for the requested DMA data transfer based on the size of the requested DMA data transfer and profile data of the I/O adapter, the DMA transfer mode being one of a data copy mode and a map/unmap mode.