Concerning the problem that how to make full use of the resources in cloud infrastructure to satisfy various and high reliable fault tolerant requirements of cloud application systems for cloud application tenants, a cloud application tenant and service provider oriented fault tolerance as a service method in cloud platform was proposed based on virtual machine deployment policy. According to specific fault tolerant requirements from cloud application tenants, suitable fault tolerance methods with corresponding fault tolerant levels were adopted. Then, the revenue and resource usage of service provider were computed and optimized. Based on the analysis, virtual machines which providing fault tolerant services were well deployed, which could make full use of the resources in virtual machine level to provide more reliable fault tolerant services for cloud application systems and their tenants. The experimental results show that the proposed method could guarantee the revenue of service providers, and achieve more flexible and more reliable fault tolerant services for cloud application systems with multiple tenants.

When the pipelining loop has a great number of iterations, or the size of its body is large, but the number of available threads is small, the workload between two synchronizations of a thread is so heavy, which produces pretty low degree of parallelism. The traditional trade-off approach based on loop tiling cannot handle the above situation. To solve this problem, a pipelining granularity decreasing approach based on loop tiling was proposed. The optimal pipelining granularity was obtained by building the cost model for pipelining loop and a pipelining granularity optimizing algorithm was implemented. By measuring the wavefront loops of Finite Difference Relaxation (FDR) and the representative loops of Finite Difference Time Domain (FDTD), the loops show better performance improvement by using the proposed algorithm than the traditional one.