1. A method for selectively monitoring store instructions to support transactional execution of a process, comprising: encountering a store instruction during transactional execution of a block of instructions in a program, wherein changes made during the transactional execution are not committed to the architectural state of a processor until the transactional execution successfully completes; examining an op code of the store instruction or an address of the store instruction to determine whether the store instruction is a monitored store instruction or an unmonitored store instruction; if the store instruction is a monitored store instruction, performing a corresponding store operation, and store-marking a cache line associated with the store instruction to facilitate subsequent detection of an interfering data access to the cache line from another process; and if the store instruction is an unmonitored store instruction, performing the corresponding store operation without store-marking the cache line.