Exploiting parallelism in the simulation of general purpose graphics processing unit program

The simulation is an important means of performance evaluation of the computer architecture. Nowadays, the serial simulation of general purpose graphics processing unit (GPGPU) architecture is the main bottleneck for the simulation speed. To address this issue, we propose the intra-kernel parallelization on a multicore processor and the inter-kernel parallelization on a multiple-machine platform. We apply these two methods to the GPGPU-sim simulator. The intra-kernel parallelization method firstly parallelizes the serial simulation of multiple compute units in one cycle. Then it parallelizes the timing and functional simulation to reduce the performance loss caused by the synchronization between different compute units. The inter-kernel parallelization method divides multiple kernels of a CUDA program into several groups and distributes these groups across multiple simulation hosts to perform the simulation. Experimental results show that the intra-kernel parallelization method achieves a speed-up of up to 12 with a maximum error rate of 0.009 4% on a 32-core machine, and the inter-kernel parallelization method can accelerate the simulation by a factor of up to 3.9 with a maximum error rate of 0.11% on four simulation hosts. The orthogonality between these two methods allows us to combine them together on multiple multi-core hosts to get further performance improvements.     

轨道交通高峰时段乘客生理信号特征提取

我国作为人口大国,公共场所拥挤现象越来越普遍,影响着个体身心健康的发展。但由于拥挤环境的复杂性和存在的社会伦理问题,目前的研究主要集中在心理学角度的定性论述。打破传统研究方式,通过设计实验,实时记录上海地铁早高峰期间乘客血氧饱和度、脉率和呼末二氧化碳生理指标,并运用频谱分析和小波包分解技术进行分析对比,将车厢拥挤环境对乘客的基本生理参数的影响定量表述。结果反映拥挤环境会对乘客呼吸系统产生较大影响,并为改善地铁拥挤和安全管理提供了新思路。