中种学林水学计算机科学与术系 versity ResearchhIssuesna parallel computation models(2) Asynchronous PRAM APRAM or MIMD-SM, Used for medium grain parallel computation centralized shared memory asynchronous operation, Read/write shared variable communication, Explicit synchronous(barrier, etc. Computation in APRAM Computation Consists of global phases separated by barriers: in a phase all processors execute operation asynchronized the last instruction must be a synchronization instruction Advantages: Preserving much of simplicity of PRAM, better programmability, program must be correctness, easy to analyze complexity Disadvantages: Unsuitable for MIMD computers with distributed memory NHPCC at Hefei 2021/2/6 10NHPCC at Hefei 10 2021/2/6 Research Issues – Parallel computation models(2) ▪ Asynchronous PRAM ▪ APRAM or MIMD-SM, Used for medium grain parallel computation, Centralized shared memory, Asynchronous operation, Read/write shared variable communication, Explicit synchronous (barrier, etc.). ▪ Computation in APRAM ▪ Computation Consists of global phases separated by barriers: in a phase all processors execute operation asynchronized, the last instruction must be a synchronization instruction. ▪ Advantages: Preserving much of simplicity of PRAM, better programmability, program must be correctness, easy to analyze complexity. ▪ Disadvantages: Unsuitable for MIMD computers with distributed memory