Remotely controlled message queue

1. A computer system for managing data transfer, the system comprising:

a memory;

a processor communicatively coupled to said memory;

a send component;

a receive component having a message queue and a controller;

a single link interface communicatively coupling said send component to said receive component;

said single link interface comprising at least one mainline channel and a sideband channel; and

a mainline data transfer mechanism of said at least one mainline channel having higher overhead than a sideband data transfer mechanism of said sideband channel, wherein said mainline data transfer mechanism comprises a different data transfer mechanism than said sideband data transfer mechanism;

the computer system configured to perform a method comprising:

analyzing, by said send component, according to at least one mainline message criterion, messages to be transmitted;

classifying, by said send component, messages to be transmitted that do not meet said at least one mainline message criterion as sideband messages;

transmitting, by said send component, mainline channel messages over said at least one mainline channel from said send component to said receive component according to said mainline data transfer mechanism;

based at least in part on classifying messages to be transmitted that do not meet said at least one mainline message criterion as sideband messages, transmitting, by said send component, sideband channel messages over said sideband channel from said send component to said message queue of said receive component according to said sideband data transfer mechanism;

utilizing said controller to control a flow of said sideband channel messages to said message queue without relying on sending feedback to said send component about said flow;

based on a determination that the single link interface is currently transmitting the mainline channel messages, delaying transmitting the sideband channel messages until transmitting the mainline channel messages is complete; and

based on a determination that the single link interface is currently transmitting the sideband channel messages, generating a feedback indicating that the single transmission link is busy.

2. The computer system of claim 1 wherein said transmitting sideband channel messages comprises:

writing said sideband channel messages to a transmit register of said send component; and

said transmit register placing said sideband channel messages on said sideband channel for transmission without relying on receiving feedback about said flow of said sideband channel messages to said message queue.

3. The system of claim 1 wherein said sideband channel messages comprise administrative messages.

4. The system of claim 3 wherein said administrative messages provide information about a status of said mainline channel messages.

5. The system of claim 1 wherein said message queue is circular.

6. The system of claim 1 wherein said flow control comprises assigning additional information to said sideband channel messages.

7. The system of claim 1 wherein the method further comprises:

said transmitting said sideband channel messages is limited to transmitting fixed-maximum-length packets;

disassembling, by said send component, said sideband channel messages into sideband channel message packets having said fixed-maximum-length; and

reassembling, by said receive component, said fixed-maximum-length sideband channel message packets into said sideband channel message.

8. A computer implemented method for managing data transfer, the method comprising:

analyzing, by a send component, according to at least one mainline message criterion, messages to be transmitted;

classifying, by said send component, messages to be transmitted that do not meet said at least one mainline message criterion as sideband messages;

transmitting, by said send component, mainline channel messages from said send component to a receive component over at least one mainline channel of a single link interface, said single link interface communicatively coupling said send component to said receive component;

based at least in part on classifying messages to be transmitted that do not meet said at least one mainline message criterion as sideband messages, transmitting, by said send component, said sideband channel messages from said send component to a message queue of said receive component over a sideband channel of said single link interface;

wherein a mainline data transfer mechanism of said at least one mainline channel includes higher overhead than a sideband data transfer mechanism of said sideband channel;

wherein said mainline data transfer mechanism comprises a different data transfer mechanism than said sideband data transfer mechanism;

utilizing a controller of said receive component to control a flow of said sideband channel messages to said message queue without relying on sending feedback to said send component about said flow;

based on a determination that the single link interface is currently transmitting the mainline channel messages, delaying transmitting the sideband channel messages until transmitting the mainline channel messages is complete; and

based on a determination that the single link interface is currently transmitting the sideband channel messages, generating a feedback indicating that the single transmission link is busy.

9. The computer implemented method of claim 8 wherein said transmitting sideband channel messages comprises:

writing said sideband channel messages to a transmit register of said send component; and

said transmit register placing said sideband channel messages on said sideband channel for transmission without relying on receiving feedback about said flow of said sideband channel messages to said message queue.

10. The computer implemented method of claim 8 wherein said sideband channel messages comprise administrative messages.

11. The computer implemented method of claim 10 wherein said administrative messages provide information about a status of said at least one mainline channel messages.

12. The computer implemented method of claim 8 wherein said flow control comprises assigning additional information to said sideband channel messages.

13. The computer implemented method of claim 8 further comprising:

said transmitting said sideband channel messages is limited to transmitting fixed-maximum-length packets;

disassembling, by said send component, said sideband channel messages into sideband channel message packets having said fixed-maximum-length; and

reassembling, by said receive component, said fixed-maximum-length sideband channel message packets into said sideband channel message.

14. A computer program product for managing data transfer, the computer program product comprising:

a computer readable storage medium having program instructions embodied therewith wherein the computer readable storage medium is not a transitory signal per se, the program instructions readable by a processing circuit to cause the processing circuit to perform a method comprising:

analyzing, by a send component, according to at least one mainline message criterion, messages to be transmitted;

classifying, by said send component, messages to be transmitted that do not meet said at least one mainline message criterion as sideband messages;

transmitting, by said send component, mainline channel messages from said send component to a receive component over at least one mainline channel of a single link interface, said single link interface communicatively coupling said send component to said receive component; and

based at least in part on classifying messages to be transmitted that do not meet said at least one mainline message criterion as sideband messages, transmitting, by said send component, said sideband channel messages from said send component to a message queue of said receive component over a sideband channel of said single link interface;

wherein a mainline data transfer mechanism of said at least one mainline channel includes higher overhead than a sideband data transfer mechanism of said sideband channel;

utilizing a controller of said receive component to control a flow of said sideband channel messages to said message queue without relying on sending feedback to said send component about said flow;

based on a determination that the single link interface is currently transmitting the mainline channel messages, delaying transmitting the sideband channel messages until transmitting the mainline channel messages is complete;

based on a determination that the single link interface is currently transmitting the sideband channel messages, generating a feedback indicating that the single transmission link is busy.

15. The computer program product of claim 14 wherein said transmitting sideband channel messages comprise:

writing said sideband channel messages to a transmit register of said send component; and

said transmit register placing said sideband channel messages on said sideband channel for transmission without relying on receiving feedback about said flow of said sideband channel messages to said message queue.

16. The computer program product of claim 14 wherein:

said sideband channel messages comprise administrative messages; and

said administrative messages provide information about a status of said at least one mainline channel messages.

17. The computer program product of claim 14 , the method performed by the processor circuit further comprising:

said transmitting said sideband channel messages is limited to transmitting fixed-maximum-length packets;

disassembling, by said send component, said sideband channel messages into sideband channel message packets having said fixed-maximum-length; and

reassembling, by said receive component, said fixed-maximum-length sideband channel message packets into said sideband channel message.