International Business Machines Corporation

Neta Jacob Amit

John Michael Marberg

Uri Shani

A multi-processor computer system executes a single-thread program having a plurality of callable procedures. The local memory of each processor contains a program stack, the object code of each procedure that executes on that processor, and an agent object. In addition, the local memory contains a c-stub module for each procedure executable on a different processor, and a s-stub module for each local procedure that can be called by a remote procedure. When a procedure P1 executing on processor A calls a procedure P2 which executes in processor B, it issues a local call to P2's c-stub in processor A's local memory. The P2 c-stub then invokes the agent process in processor A, which communicates with a corresponding agent process in processor B. The agent process in processor B causes P2's s-stub in processor B to issue a local call to procedure P2. The return from a procedure follows the same path in reverse. Each processor independently maintains its own version of the program stack, with stack entries referencing the locally executable procedures, local stubs, or local agents. As a result, remote procedure calls are not constrained by the past calling history of a process. A procedure P1 in processor A may call a procedure P2 in processor B, which may in turn call another procedure P3 in processor A. It is therefore possible to convert a conventional single-thread program for operation on a multi-processor system without any significant modification to the source code.

Growing community of inventors

Haifa, Israel

Neta Jacob Amit