Research On Scheduling Of Multi-thread With Critical Section For Multi-core Processor

With the development of multi-core and Multi-thread technology,multi-thread scheduling on multi-core processor has become a hot research topic.Due to the complexity of multi-core processor structure,resource management is more difficult.When multi-thread runs on multi-core platform,how to make better use of multi-core resources,allowing multi-thread to perform correctly and quickly,is related to the improvement of system performance.An excellent thread scheduling algorithm for multicore can make full use of the resources more effectively,improve the system throughput and reduce the response time and turnover time without undermining fairness.In general.a multi thread model is proposed,and different scheduling methods are proposed for different multi-core platforms based on this model in the research on scheduling method for multi-core and multi-thread.In the multi-thread model,a lot of people choose DAG chart.But traditional DAG diagram has its own defects,for example,can not describe the relationship between tasks.This paper is aimed at the threads with critical sections and proposes a multi-threads-scheduling medal based on Forest which could maintain the dependencies between front and rear,shared data and shared resources between tasks.To improve the system's performance and diminish the spare time of computing resource,the paper also propose a scheduling algorithm——CSTS(Critical Section Thread Scheduling).Based on critical section,the algorithm analyzes the shared resource between threads and execute the threads with the same critical section on the same core.Because of the characteristic of the critical section,it becomes an important factor limiting system performance.In order to reduce the congestion caused by the critical section,the algorithm propose a method to calculate the priority based on critical section.The algorithm also considers the fairness.In multi-core processors,the heterogeneous multi-core processors are more practical than homogeneous multi-core because they have asymmetric cores.Therefore,the paper optimize the Accelerated Critical Section Algorithm using different abilitiy of different cores in heterogeneous multi-core processors except for designing new multi-thread model and the algorithm for this forest model for general multi-core processors.The algorithm can effectively shorten the execution time of the thread in the critical section,but it is likely to cause the problem of the serial of the independent critical section.An Improvement Accelerating Critical Section algorithm is proposed for the improvement of the Accelerating Critical Section algorithm.The algorithm tracks the execution of threads on the cores that contain the critical section and changes the priority factor of threads.It use the priority factor to guide the threads' dynamic migration between the high-performance core and the low-performance cores.The algorithm can accelerate the excution of the critical section and effectively solve the threads block problem on highperformance core that the Accelerating Critical Section causes.In this paper,the simulation experiment is carried out to validate the algorithm based on the forest thread model.The algorithm has higher utilization of computing resources and higher performance than similar method for critical section intensive threads.For the Improved Accelerated Critical Section Algorithm,the Simics is used to simulate heterogeneous multi-core processors system and the inputs are 12 loads with intensive critical sections.The experimental results show that the algorithm is better than the original Accelerating Critical Section algorithm and the Simple Algorithm.