Bit Contiguous Memory Allocation for Processing In Memory

Given the recent resurgence of research into processing in or near memory systems, we find an ever increasing need to augment traditional system software tools in order to make efficient use of the PIM hardware abstractions. One such architecture, the Micron In-Memory Intelligence (IMI) DRAM, provides a unique processing capability within the sense amp stride of a traditional 2D DRAM architecture. This accumulator processing circuit has the ability to compute both horizontally and vertically on pitch within the array. This unique processing capability requires a memory allocator that provides physical bit locality in order to ensure numerical consistency. In this work we introduce a new memory allocation methodology that provides bit contiguous allocation mechanisms for horizontal and vertical memory allocations for the Micron IMI DRAM device architecture. Our methodology drastically reduces the complexity by which to find new, unallocated memory blocks by combining a sparse matrix representation of the array with dense continuity vectors that represent the relative probability of finding candidate free blocks. We demonstrate our methodology using a set of pathological and standard benchmark applications in both horizontal and vertical memory modes.