Extending Cache In A Multi-Processor Computer

A method of extending cache in a multi-processor computer, the method comprising:

• receiving from a donor processor, by a requesting processor, a donor-ready message indicating that a donor processor's cache is available for ownership transferment;
• in response to receiving the donor-ready message, transmitting to the donor processor, by the requesting processor, an ownership-request message requesting ownership of the donor processor's cache by the requesting processor;
• in response to transmitting the ownership-request message, receiving, by the requesting processor, an ownership-grant message indicating an intention of the donor processor to transfer ownership of the donor processor's cache to the requesting processor;
• and
• in response to receiving the ownership-grant message, transmitting, by the requesting processor, an ownership-claim message indicating that the requesting processor intends to claim ownership of the donor processor's cache.

An apparatus for extending cache in a multi-processor computer, the apparatus comprising a computer processor, a computer memory operatively coupled to the computer processor, the computer memory having disposed within it computer program instructions that when executed by the computer processor cause the apparatus to carry out the steps of:

• detecting, by a donor processor, nonuse of a donor processor's cache;
• in response to detecting the nonuse, broadcasting to one or more processors in the multi-processor computer, by the donor processor, a donor-ready message indicating the donor processor's cache is available for ownership transferment;
• in response to the broadcast of the donor-ready message, receiving from a first requesting processor, by the donor processor, a first ownership-request message requesting ownership of the donor processor's cache by the first requesting processor;
• in response to receiving the first ownership-request message, transmitting to the first requesting processor, by the donor processor, an ownership-grant message indicating an intention of the donor processor to transfer ownership of the donor processor's cache to the first requesting processor;
• and
• in response to transmitting the ownership-grant message, receiving from the first requesting processor, by the donor processor, an ownership-claim message indicating that the first requesting processor intends to claim ownership of the donor processor's cache.

A computer program product for extending cache in a multi-processor computer, the computer program product disposed upon a computer readable medium, the computer program product comprising computer program instructions capable, when executed, of causing a computer to carry out the steps of:

• detecting, by a donor processor, nonuse of a donor processor's cache;
• in response to detecting the nonuse, broadcasting to one or more processors in the multi-processor computer, by the donor processor, a donor-ready message indicating the donor processor's cache is available for ownership transferment;
• in response to the broadcast of the donor-ready message, receiving from a first requesting processor, by the donor processor, a first ownership-request message requesting ownership of the donor processor's cache by the first requesting processor;
• in response to receiving the first ownership-request message, transmitting to the first requesting processor, by the donor processor, an ownership-grant message indicating an intention of the donor processor to transfer ownership of the donor processor's cache to the first requesting processor;
• and
• in response to transmitting the ownership-grant message, receiving from the first requesting processor, by the donor processor, an ownership-claim message indicating that the first requesting processor intends to claim ownership of the donor processor's cache.