A microprocessor comprising: a cache including a tag array; a tag pipeline that arbitrates access to the tag array; and a pattern detector, the pattern detector comprising: a register; a decoder that decodes transaction type identifiers (222, 224) of tagpipe arbs advancing through the tag pipeline, wherein tagpipe arbs are transactions to access the tag array; and an accumulator that accumulates into the register the transaction type identifiers of a plurality of tagpipe arbs advancing through the tag pipeline; and characterized in that the pattern detector accumulates a history of every kind of tagpipe arb advancing through the tag pipeline, as a stored history; and in that the pattern detector is configured to trigger a capture or recovery routine if the stored history meets one or more predetermined conditions, and wherein one of the one or more predetermined conditions is one of: that a counted number of replays, compared to a counted number of completes, exceeds one or more thresholds, or that a counted number of replays during a most recent period is approximately equal to a counted number of replays during a next most recent period. a cache including a tag array; a tag pipeline that arbitrates access to the tag array; and a pattern detector, the pattern detector comprising: a register; a decoder that decodes transaction type identifiers (222, 224) of tagpipe arbs advancing through the tag pipeline, wherein tagpipe arbs are transactions to access the tag array; and an accumulator that accumulates into the register the transaction type identifiers of a plurality of tagpipe arbs advancing through the tag pipeline; and characterized in that the pattern detector accumulates a history of every kind of tagpipe arb advancing through the tag pipeline, as a stored history; and in that the pattern detector is configured to trigger a capture or recovery routine if the stored history meets one or more predetermined conditions, and wherein one of the one or more predetermined conditions is one of: that a counted number of replays, compared to a counted number of completes, exceeds one or more thresholds, or that a counted number of replays during a most recent period is approximately equal to a counted number of replays during a next most recent period. a register; a decoder that decodes transaction type identifiers (222, 224) of tagpipe arbs advancing through the tag pipeline, wherein tagpipe arbs are transactions to access the tag array; and an accumulator that accumulates into the register the transaction type identifiers of a plurality of tagpipe arbs advancing through the tag pipeline; and characterized in that the pattern detector accumulates a history of every kind of tagpipe arb advancing through the tag pipeline, as a stored history; and in that the pattern detector is configured to trigger a capture or recovery routine if the stored history meets one or more predetermined conditions, and wherein one of the one or more predetermined conditions is one of: that a counted number of replays, compared to a counted number of completes, exceeds one or more thresholds, or that a counted number of replays during a most recent period is approximately equal to a counted number of replays during a next most recent period.