Lock architecture for large scale system

A process executed by each processor in question (10) among for the allocation of shared resources in a computer system having several processors (10, 11, 12, 13) for requesting a resource in the computer system, said process being executed by each processor, the computer system comprising an atomic operation (2) for reading and modifying a lock that controls the use of said resource, characterized in that:

• the atomic operation (2) consists of incrementing a counter wherein a predetermined value defines a first state of the lock;
• the atomic operation (2) is followed by a first test (3) for triggering a first step (8) if the counter does not have a predetermined value at the start of the atomic operation (2) and for triggering a second step (14) for taking control of the resource if the counter has a predetermined value at the start of the atomic operation (2);
• the first step (8) setting a data item specific to a first processor (10) in question to a second value such that the first processor (10) in question loops to a reading of its specific data item until the detection of a first value of its specific data item, which triggers the step for taking control of the resource (14);
• the second step (14) being followed by a second test (16) after the release of the resource, for triggering a third step (17) if a decrementation of the counter does not result in the predetermined value and for triggering a fourth step (18) in the opposite case;
• the third step (17) determining a second processor (11, 12, 13) distinct from the first processor (10) in question, wherein a specific data item is set to the second value, setting the specific data item of the determined second processor (11, 12, 13) to the first value, and triggering the fourth step (18);
• the fourth step (18) comprising a second atomic operation for decrementing the counter.