1. A method for operating a SIMD packet parsing cluster, wherein the cluster includes a plurality of M>=2 packet parsing engines 1 to M, and the cluster further includes a shared memory and an instruction memory storing a plurality of instructions to be performed by each of the engines, and wherein the instructions include one or more memory accessing instructions that require accessing the shared memory, the method comprising: transmitting the instructions to the engines for the instructions to be executed by the engines; for each of the engines 2 to M, delaying execution of each of the memory accessing instructions by a delay time compared to a previous engine; and each one of the engines performing one of the memory accessing instructions at a time that the other engines are not performing one of the memory accessing instructions by inserting a lag time between each two consecutive memory accessing instructions for engine 1, the lag time being greater than or equal to a time enabling the 2 to M engines to complete memory accessing instruction corresponding to the first of the two consecutive memory accessing instructions.