Behavior Gaps and Relations between Operating System and Applications on Accessing DRAM

Detailed analyses of the behaviors of operating system and applications are significant for taking full advantage of the precious hardware resources and improving performance. This paper focus on their DRAM access behaviors based on access proportion and row-buffer miss ratio (RBM). The access proportions of Kernel and User vary greatly in different stages throughout the lifetime of a process. Most of the row-buffer misses are caused by the one having higher access proportion. By analyzing the RBM series through ARMA model, we found that User´s DRAM accesses only have short-term influences on its behavior, while the Kernel´s influences are relatively deeper. The ARMA model for the RBM series is able to predict the future RBMs, which are profound basis to schedule the DRAM access commands. The results of Gaussian Fitting show that Kernel and User are tightly correlated on accessing DRAM, especially in the steady stage and the end stage of a process´s life cycle. Based on this close relation, it is possible to estimate the DRAM access behaviors of the other one according to the one whose behaviors have been known. System-calls that obviously affect the access proportions and RBMs are also revealed in this paper.