TSS: Applying two-stage sampling in micro-architecture simulations

Accelerating micro-architecture simulation is becoming increasingly urgent as the complexity of workload and simulated processor increases. This paper presents a novel two-stage sampling (TSS) scheme to accelerate the sampling-based simulation. It firstly selects some large samples from a dynamic instruction stream as candidates of detail simulation and then samples some small groups from each selected first stage sample to do detail simulation. Since the distribution of standard deviation of cycle per instruction (CPI) is insensitive to microarchitecture, TSS could be used to speedup design space exploration by splitting the sampling process into two stages, which is able to remove redundant instruction samples from detail simulation when the program is in stable program phase (standard deviation of CPI is near zero). It also adopts systematic sampling to accelerate the functional warm-up in sampling simulation. Experimental results show that, by combining these two techniques, TSS achieves an average and maximum speedup of 1.3 and 2.29 over SMARTS, with the average CPI relative error is less than 3%. TSS could significantly accelerate the time consuming iterative early design evaluation process.