1. A method of processing a plurality of flows, the method comprising: computing, by a first processing element within a plurality of processing elements, an index into a structure stored in memory, the index being based on, at least in part, a first unique flow ID of a first flow and a property of the structure; storing by the first processing element, a value in the structure at the location identified by the index, if a specified condition associated with the first flow is satisfied, the storing step being an atomic operation, and the stored value corresponding to the first unique flow ID, wherein a false positive probability of computing the index based on, at least in part, a second unique flow ID of a second flow and computing a value corresponding to the second flow that is same as the stored value is less than a false negative probability of computing the index based on, at least in part, a third unique flow ID of a third flow and computing a value corresponding to the third flow that is different from the stored value; computing, by a second processing element within the plurality of processing elements, a value corresponding to the unique flow ID and the index; comparing by the second processing element the computed value with the value stored at the location identified by the index; and controlling, by the second processing element, processing of the flow based on, at least in part, a result of the comparison.