Hybrid Tracking of Transaction Read and Write Sets

A computer program product for tracking of processor transactional read and write sets, the computer program product comprising a computer readable storage device having program code embodied therewith, the program code executable by a processing unit to:

• maintain a non-speculative read set indication of non-speculative reads of data stored in a cache by a processor cache unit for a transaction by a first requestor;
• maintain a non-speculative write set indication of non-speculative writes of written data stored in the cache by the processor cache unit by the first requestor;
• maintain a queue of addresses corresponding to speculatively executed memory read instructions corresponding to speculative members of a read set;
• maintain a queue of addresses corresponding to speculatively executed memory write instructions corresponding to speculative members of a write set;
• perform a transaction interference resolution responsive to receiving a request for data by a remote processor, including determining a potential transaction interference exclusively conflicting with a speculative instruction;
• and
• hold a response to the received request until the speculative instruction is in a state selected from the group of:
• committed and flushed.

A computer system comprising:

• a processing unit operatively coupled to memory;
• a tool in communication with the processing unit to track processor transactional read and write sets, including:
• maintain a non-speculative read set indication of non-speculative reads of data stored in a cache by a processor cache unit for a transaction by a first requestor;
• maintain a non-speculative write set indication of non-speculative writes of written data stored in the cache by the processor cache unit by the first requestor;
• maintain queue of addresses corresponding to speculatively executed load instructions corresponding to speculative members of a read set;
• maintain a queue of addresses corresponding to speculatively executed store instructions corresponding to speculative members of a write set;
• perform a transaction interference resolution responsive to receiving a request for data by a remote processor, including determining a potential transaction interference exclusively conflicting with a speculative instruction;
• and
• hold a response to the received request until the speculative instruction is in a state selected from the group of:
• committed and flushed.