Patent ID: 8589638
Filing Date: 2013-11-19
Classification: G06F

Abstract:
1. Data access control circuitry for controlling an order of data access requests to a data storage recipient, said data storage recipient being a point of convergence of said data with no downstream reconvergence and no side effects of said read or write requests, said data access requests comprising read requests received as a stream of requests on a read channel and write requests received as a stream of requests on a write channel, each of said streams of requests further comprising corresponding barrier transactions, said corresponding barrier transactions indicating corresponding points in said streams of requests that at least some requests should not be reordered around in order to maintain data consistency, said data access control circuitry comprising: barrier response generating circuitry located on said read and said write channels and being responsive to receipt of one of said barrier transactions: said data access control circuitry comprises a point of data consistency on said write channel prior to said data storage recipient and said data access control circuitry comprises comparison circuitry configured to compare said barrier context value of each write request to be issued to said data storage recipient with said barrier context values of at least some pending read requests, said pending read requests being requests received at said data access control circuitry but not yet issued to said data storage recipient and: