Method, apparatus and system for transmitting multiple input/output (i/o) requests in an i/o processor (iop)

An apparatus for sending I/O requests from an input/output processor (IOP) to an I/O device coupled to the IOP, the apparatus comprising:

• a request queue configured for receiving I/O requests;
• a device queue configured for queuing a plurality of I/O requests, the device queue having an input end and an output end;
• a queuing thread coupled between the request queue and the device queue, wherein the queuing thread is configured to pull I/O requests from the request queue and deliver pulled I/O requests to the input end of the device queue;
• a plurality of I/O threads for processing multiple I/O requests at a time for transmission to the I/O device;
• and
• a plurality of active I/Os corresponding to the plurality of I/O threads and coupled between the device queue and a respective one of the I/O threads, wherein each I/O thread is configured to transfer an I/O request from the output end of the device queue to a corresponding active I/O,
• wherein at least one of the queuing thread and the plurality of I/O threads are configured to promote an I/O request ahead of at least one other I/O request from the device queue to an active I/O based on a set of promotion requirements.

A computer readable medium having instructions stored thereon that, when executed by a processor, carry out a method for sending I/O requests from an input/output processor (IOP) to an I/O device coupled to the IOP, the instructions comprising:

• receiving a plurality of I/O requests;
• queuing the plurality of I/O requests in a device queue based on the order in which the I/O requests were received;
• moving I/O requests from the device queue to one of a plurality of active I/Os corresponding to a plurality of I/O threads, wherein each I/O thread is configured to transfer an I/O request from the device queue to a corresponding active I/O, and wherein the I/O threads are configured to process multiple I/O requests at a time for transmission to the I/O device;
• and
• controlling the movement of an I/O request from the device queue to one of the active I/Os based on the set of promotion requirements.