1. A method comprising: beginning execution of an atomic transaction in a system having a transactional memory; during executing of the atomic transaction: receiving a signal interrupt; determining whether an interrupt handler for processing the signal interrupt includes an instruction that would be detectable external to the atomic transaction; in response to determining the interrupt handler does include the instruction that would be detectable external to the atomic transaction, ceasing execution of the interrupt handler and continuing execution of the atomic transaction; and in response to determining the interrupt handler does not include the instruction that would be detectable external to the atomic transaction, executing the instruction.