Filtering of transactional memory operations using associative tables

A computer-implemented system for efficiently logging memory accesses in a transactional memory system, the system comprising:

• a computer processing unit;
• and
• one or more computer-readable media containing:
• one or more transactional memory logs configured to allow a plurality of entries for each of a plurality of memory addresses;
• and
• an associative filtering table other than the logs comprising a hash table comprising one or more hash table entries each indicating a sequential memory transaction number as an indication of a memory transaction and a memory address;
• wherein the hash table is configured such that:
• the computer processing unit determines, for a given memory address, whether an entry has been made in one of the one or more transactional memory logs within a current memory transaction;
• and
• when no entry has been made in the one or more transactional logs for the memory address, the computer processing unit creates an entry for that memory address;
• and
• wherein:
• each memory transaction is identified by a higher sequential memory transaction number than the one prior to it up to a pre-defined limit;
• and
• if a sequential memory transaction number reaches the pre-defined limit,
• the sequential memory transaction number is reset;
• and
• the hash table is cleared.

One or more computer-readable storage media containing instructions which, when executed by a computer, cause the computer to perform a method for logging memory accesses in a transactional memory system, the method comprising:

• receiving a request to add an entry for a transactional memory access taking place at a memory location into one or more transactional memory logs;
• checking a filtering hash table for the log to determine if a log entry is known to have been added for the memory location within a current memory transaction;
• if a log entry is known to have been logged for the memory location within the current memory transaction, leaving logs for the memory location in their current state;
• and
• if a log entry is not known to have been logged for the memory location within the current memory transaction:
• writing a hash table entry to the filtering hash table, the writing comprising performing a logical or mathematical operation on the value of the memory location and the value of an identifier for the current memory transaction, and the hash table entry recording that a log entry has been logged for the memory location;
• adding a log entry for the memory location into the transactional memory log;
• upon entry into a memory transaction,
• incrementing a transactional count;
• and
• setting the identifier for the current memory transaction to the incremented value of the count;
• and
• when the transactional count reaches a pre-defined limit:
• resetting the count;
• and
• clearing the hash table.