A Study of High Concurrency Workload Influence on Modern Processor

This paper evaluates how concurrent users influence on processors and caches behavior of DBMSs on today´s hardware platform. AS TPC-C is currently the only active OLTP benchmark supported by the TPC. the main properties of TPC-C are that the database size and the number of users scale linearly with the throughput. Because main memory capability is limited and I/O is not a bottleneck, TPC-C benchmark is unsuitable for MMDBMSs. According to those properties, this paper proposes the ETPC-C benchmark for MMDBMSs. Then using hardware counters, we evaluate ETPC-C workload on MMDBMS. We find that the miss stall time is mostly spent on on-CPU-chip caches, that is, the first and second level cache misses are dominant. Furthermore, we find instruction cache (I-cache) stall time of on-CPU-chip is a major component to the memory stall time. The smaller the emulated users, the more proportion the i-cache stall time of on-CPU-chip contributes to the memory stall time. However, if employing index, the system under test (SUT) has more total i-cache stall time than the SUT without index at the same number of emulated users and data population.