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Method for improved bus and memory utilization of spin-locks

IP.com Disclosure Number: IPCOM000016697D
Publication Date: 2003-Jul-09
Document File: 1 page(s) / 50K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a method for improved bus and memory utilization of spin-locks. Benefits include improved functionality and improved performance.

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Method for improved bus and memory utilization of spin-locks

Disclosed is a method for improved bus and memory utilization of spin-locks. Benefits include improved functionality and improved performance.

Background

        � � � � � In a multiprocessing environment when more than one processor must synchronize with another processor or acquire a lock before it accesses a shared resource, a spin-lock or similar mechanism is used.

        � � � � � A spin-lock is a software loop that attempts to use an atomic operation to perform a read-modify-write operation on memory. The content of the memory notifies all the involved parties whether the resource is busy or free. If the resource is busy and in use by a processor, another processor may spin and attempt to perform the read-modify-write operation to the memory. All or a portion of the memory is locked while the instruction is being performed. The second processor is prohibited from performing the access to memory.

        � � � � � Conventionally, acquiring a lock involved endless repeated spinning on the locked memory, which consumed memory bus bandwidth and disturbing the other processor that is performing the read-modify-write operation.

Description

        � � � � � The disclosed method is two instruction pairs, Monitor/Mwait and Monitor/MwaitExchange.� They block the awaiting processor until the memory read-modify-write operation by another processor is complete. This procedure is an expanded use of the conventional instructions for spin-lock loops and...