Serializing wrapping trace buffer via a compare-and-swap instruction

Abstract

Embodiments of the disclosure serializing wrapping of a circularly wrapping trace buffer via a compare-and-swap (CS) instruction by a method including executing a CS loop to advance to a location in the buffer indicated by a next free pointer. The method also includes incrementing a master wrap sequence number each time the next free pointer returns to a top of the buffer and executing another CS loop to increment a wrap number stored in a trace block corresponding to the location indicated by the next free pointer. Based upon determining that the wrap number stored in the trace block is one less than or equal to the master wrap sequence number, the method includes reserving space in a buffer associated with the trace block and storing the wrap number stored in the trace block as an old wrap number and incrementing a use-count of the trace block.