Semaphore management subsystem for use with multi-thread processor systems

A subsystem for managing semaphores for a multi-threaded processing system which processes a plurality of threads comprising:

• a memory having a plurality of storage areas one for each of the threads in the multi-threaded processing system, each of the storage areas including a first part for storing at least one first indicia for identifying at least one unique semaphore from a plurality of semaphores utilized by the multi-threaded processing system and a second part for storing a second indicia for indicating a locked status for a semaphore identified by the stored first indicia;
• first logic circuit responsive to a request for a semaphore from a thread for examining the contents of all of the storage areas to determine if a locked semaphore corresponding to the requested semaphore is stored in any of the storage areas;
• second logic circuit for storing the requested semaphore in the storage area associated with the requesting thread along with a status indicating a locked semaphore if the requested semaphore is not found in the search and notifying the requesting thread that the request is granted;
• third logic circuit for rejecting the request if the requested semaphore is found in the memory associated with the requesting thread;
• and
• fourth logic circuit for holding the semaphore request in abeyance if the requested semaphore is found in a memory not associated with the requesting thread, the fourth logic circuit completing the semaphore lock request with an indication that no semaphore was locked if the request includes a set time out enable bit.

In a multi-threaded processing system a method for managing semaphores comprising the following steps:

• establishing a memory having a plurality of storage areas each of which includes a first part for storing at least one first indicia for identifying at least one unique semaphore from a plurality of semaphores utilized by the multi-threaded processing system and a second part for storing a second indicia for indicating a locked status for a semaphore identified by the stored first indicia;
• receiving a semaphore lock request from a thread, examining the contents of all of the storage areas to determine if a semaphore corresponding to a requested semaphore is stored in locked status in any of the storage areas;
• if a semaphore in locked status corresponding to the requested semaphore is not found, storing the requested semaphore in a storage area along with a locked status indicia and notifying the requesting thread that the request is granted;
• rejecting the request if the requested semaphore is found in the memory and is locked by the requesting thread;
• holding the semaphore request in abeyance if the requested semaphore is found in the memory but is not locked by the requesting thread;
• and
• completing the semaphore lock request with an indication that no semaphore was locked if the request includes a set time out enable bit.

In a multi-threaded processing system which processes a plurality of threads, a method for managing semaphores comprising the following steps:

• establishing a memory having a storage area for each of the threads each of which includes a first part for storing at least one first indicia for identifying at least one unique semaphore from a plurality of semaphores utilized by the multi-threaded processing system and a second part for storing a second indicia for indicating a locked status for a semaphore identified by the stored first indicia;
• receiving a semaphore lock request from a thread, examining the contents of all of the storage areas to determine if a semaphore corresponding to a requested semaphore is stored in locked status in any of the storage areas;
• if a semaphore in locked status corresponding to the requested semaphore is not found, storing the requested semaphore in a predetermined storage area along with a locked status indicia and notifying the requesting thread that the request is granted;
• rejecting the request if the requested semaphore is found in the memory and is locked by the requesting thread;
• holding the semaphore request in abeyance if the requested semaphore is found in the memory but is not locked by the requesting thread;
• and
• completing the semaphore lock request with an indication that no semaphore was locked if the request includes a set time out enable bit.