Fast parallel search capabilities on large datasets provided by content addressable memories (CAM) are required across multiple application domains. However compared to RAM, CAMs feature high area overhead and power consumption, and as a result, they scale poorly. The proposed solution, DRAMA, enables CAM, ternary CAM (TCAM) and approximate (similarity) search CAM functionalities in unmodified commodity DRAM. DRAMA performs compare operation in a bit-serial fashion, where the search pattern (query) is coded in DRAM addresses. A single bit compare (XNOR) in DRAMA is identical to a regular DRAM read. AND and OR operations required for NAND CAM and NOR CAM respectively are implemented using nonstandard DRAM timing. We evaluate DRAMA on bacterial DNA classification and show that DRAMA can achieve 3.6 times higher performance and 19.6 times lower power consumption compared to state-of-the-art CMOS CAM based genome classification accelerator.

翻译：内容可寻址存储器（CAM）在多个应用领域中都需要具备对大型数据集进行快速并行搜索的能力。然而，与RAM相比，CAM具有较高的面积开销和功耗，因此其扩展性较差。本文提出的解决方案DRAMA可在未经改动的商用DRAM中实现CAM、三态CAM（TCAM）以及近似（相似性）搜索CAM功能。DRAMA以位串行方式执行比较操作，其中搜索模式（查询）被编码在DRAM地址中。DRAMA中的单比特比较（XNOR）与常规DRAM读取操作相同。NAND CAM和NOR CAM所需的AND与OR操作则通过非标准DRAM时序实现。我们评估了DRAMA在细菌DNA分类中的性能，结果表明，与最先进的基于CMOS CAM的基因组分类加速器相比，DRAMA可实现3.6倍的性能提升和19.6倍的功耗降低。