Abstract-In this work, we conduct a detailed memory characterization of a representative set of modern datamanagement software (Cassandra, MongoDB, OrientDB and Redis) running an illustrative NoSQL benchmark suite (YCSB). These applications are widely popular NoSQL databases with different data models and features such as in-memory storage. We compare how these data-serving applications behave with respect to other well-known benchmarks, such as SPEC CPU2006, PARSEC and NAS Parallel Benchmark. The methodology employed for evaluation relies on state-of-the-art full-system simulation tools, such as gem5. This allows us to explore configurations unattainable using performance monitoring units in actual hardware, being able to characterize memory properties. The results obtained suggest that NoSQL application behavior is not dissimilar to conventional workloads. Therefore, some of the optimizations present in state-of-the-art hardware might have a direct benefit. Nevertheless, there are some common aspects that are distinctive of conventional benchmarks that might be sufficiently relevant to be considered in architectural design. Strikingly, we also found that most database engines, independently of aspects such as workload or database size, exhibit highly uniform behavior. Finally, we show that different data-base engines make highly distinctive demands on the memory hierarchy, some being more stringent than others.

No abstract

Computer architectures have evolved to structures where communication has become an essential part of the system and most of it currently takes place inside the chip. The number of on-Chip cores and the available off-chip bandwidth is not growing at the same rate. This demands for the inclusion of more sophisticated memory hierarchies inside the chip to deal with offchip latency and bandwidth problems in order to keep on improving performance. The exhaustion of Moore's law will accelerate the use of 3D-Stacked on-chip memory hierarchies to sustain the required scalability of forthcoming CMPs. For this class of systems' memory hierarchy, coherence protocol and interconnection network are two closely related components, but which are usually designed independently. In this work we will demonstrate that network components can be coupled to coherence protocol in order to extract significant performance benefits. Making use of a well-known snoop coherence protocol, we will present different network optimizations, better able to adapt to the communication requirements of this protocol.Evaluation results show that with minimal hardware changes, for some real applications, full system performance can be improved by up to 48%.

No abstract