Hardware semaphore intended for a multi-processor system
First Claim
1. A method by which a process reserves a shared resource of a multi-processor system having an operating system so as to have access to use the shared resource, the multi-processor system having a hardware semaphore lock, the semaphore lock protecting the shared resource, comprising the steps of:
- the process performing a single read operation at a memory location representing the semaphore lock so as to reserve the semaphore lock and thus become a holder of said semaphore lock; and
the read operation simultaneously returning to the process a number of holder positions, representing a number of keyholes that are vacant at the time of reservation of the semaphore lock, wherein an allowed maximum number of vacant holder positions is arranged to be initialized in the semaphore lock by the operating system of the multi-processor system.
0 Assignments
0 Petitions
Accused Products
Abstract
The invention relates to a method in a hardware semaphore lock (L1-LN) intended for a multi-processor system, which semaphore lock (L1-LN) protects a shared resource (R1-RN) in connection with the system in such a way that only a process which has reserved the semaphore lock (L1-LN) and has thus become a holder of the lock, has access to use the resource protected by the lock. The semaphore lock (L1-LN) is reserved by a single read operation of a memory location representing the semaphore lock by the process software. The read operation returns to the process the number of vacant holder positions, i.e. keyholes vacant at the time of the reservation of the lock. The semaphore lock does not require the support of the system for atomic read/write operations.
-
Citations
24 Claims
-
1. A method by which a process reserves a shared resource of a multi-processor system having an operating system so as to have access to use the shared resource, the multi-processor system having a hardware semaphore lock, the semaphore lock protecting the shared resource, comprising the steps of:
-
the process performing a single read operation at a memory location representing the semaphore lock so as to reserve the semaphore lock and thus become a holder of said semaphore lock; and
the read operation simultaneously returning to the process a number of holder positions, representing a number of keyholes that are vacant at the time of reservation of the semaphore lock, wherein an allowed maximum number of vacant holder positions is arranged to be initialized in the semaphore lock by the operating system of the multi-processor system. - View Dependent Claims (2, 3, 4, 5)
-
-
6. A hardware semaphore lock intended for a multi-processor system having an operating system, being configured to:
-
protect a shared resource in connection with said multi-processor system;
reserve a semaphore lock at a memory location representing the semaphore lock; and
simultaneously return a number of holder positions, representing a number of keyholes, that are vacant at the time of reservation of said semaphore lock, wherein an allowed maximum number of vacant holder positions is arranged to be initialized in the semaphore lock by the operating system of the multi-processor system. - View Dependent Claims (7, 8, 9, 10, 11, 12)
-
-
13. A method comprising:
-
reserving via a process a shared resource of a multi-processor system having an operating system so as to have access to use the shared resource, the multi-processor system having a hardware semaphore lock;
protecting the shared resource by the semaphore lock;
performing a single read operation at a memory location representing the semaphore lock so as to reserve the semaphore lock and thus become a holder of said semaphore lock and so as to simultaneously return to the process a number of holder positions, representing a number of keyholes that are vacant at a time of reservation of the semaphore lock; and
arranging an allowed maximum number of vacant holder positions to be initialized in the semaphore lock by the operating system of the multi-processor system. - View Dependent Claims (14, 15, 16, 17)
-
-
18. An apparatus comprising:
-
a hardware semaphore lock intended for a multi-processor system having an operating system, said hardware semaphore lock configured to;
protect a shared resource in connection with said multi-processor system;
reserve a semaphore lock at a memory location representing the semaphore lock; and
simultaneously return a number of holder positions, representing a number of keyholes, that are vacant at a time of reservation of said semaphore lock, wherein an allowed maximum number of vacant holder positions is arranged to be initialized in the semaphore lock by the operating system of the multi-processor system. - View Dependent Claims (19, 20, 21, 22, 23, 24)
-
Specification