Parallel Programming: for Multicore and Cluster Systems- P17 pps

... literature. 4.2 Performance Metrics for Parallel Programs An important criterion for the usefulness of a parallel program is its runtime on a specific execution platform. The parallel runtime T p (n) ... Examples for synthetic benchmarks are Whetstone [36, 39], which has originally been formulated in For- tran to measure floating-point performance, and Dhrystone [174] to measure...

Ngày tải lên: 03/07/2014, 16:21

... relevant for modern and future mul- ticore processors. The second part presents parallel programming models, performance models, and parallel programming environments for message passing and shared ... WaitandNotify 320 6.2.4 Extended Synchronization Patterns . . 326 Thomas Rauber · Gudula R ¨ unger Parallel Programming For Multicore and Cluster Systems 123 vi Preface...

Ngày tải lên: 03/07/2014, 16:20

... multi- threading and multicore processors requiring an explicit specification of parallelism. 2.2 Flynn’s Taxonomy of Parallel Architectures Parallel computers have been used for many years, and many ... 2.3 (a) for an illustration. 14 2 Parallel Computer Architecture Chaps. 3 and 5. To perform message-passing, two processes P A and P B on different nodes A and B issue co...

Ngày tải lên: 03/07/2014, 16:20

... left) of β and selects the output link for forwarding the message according to the following rule: • for β k = 0, the message is forwarded over the upper link of the switch and • for β k = 1, ... switch can forward the message without 52 2 Parallel Computer Architecture Fig. 2.23 Illustration of path selection for west-first routinginan8×8mesh.The links shown as blocked are used...

Ngày tải lên: 03/07/2014, 16:20

... for the L1 cache, between 15 and 25 cycles for the L2 cache, between 100 and 1000 cycles for the main memory, and between 10 and 100 million cycles for the hard disc [137]. 2.7.3 Cache Coherency Using ... Kbytes and 8 Mbytes for the L2 cache. Typical sizes of the main memory lie between 1 Gbyte and 16 Gbytes. Typical access times are one or a few processor cycles for t...

Ngày tải lên: 03/07/2014, 16:20

... memory accesses must be atomic and since memory accesses must be performed one after another. There- fore, processors may have to wait for quite a long time before memory accesses that they have ... (4). Thus, both P 1 and P 2 may print the old value for x 1 and x 2 , respectively. Partial store ordering (PSO) models relax both the W → W and the W → R ordering required for seque...

Ngày tải lên: 03/07/2014, 16:20

... of single systems and provide an abstract view for the design and analysis of parallel programs. 3.1 Models for Parallel Systems In the following, the types of models used for parallel processing ... assignments of Fortran 90/95, see [49, 175, 122]. Other examples for data -parallel programming languages are C* and data -parallel C [82], PC++ [22], DINO [151], and High...

Ngày tải lên: 03/07/2014, 16:20

... directions. For real parallel systems, this property is usually fulfilled. 4.2 Performance Metrics for Parallel Programs 165 4.2.2 Scalability of Parallel Programs The scalability of a parallel program ... operations must be performed, and different load balancing may result, leading to different parallel execution times for different program versions. Analytical modeling can...

Ngày tải lên: 03/07/2014, 16:21

... mes- sages received in phase 2. The phases 1 and 2 can be performed simultaneously and take time 2 d . Phase 3 has to be performed after phase 2 and takes time ≤ 2 d − 1. In summary, the time 2 d +2 d −1 ... 2 d+1 −1 results. 4.4 Analysis of Parallel Execution Times The time needed for the parallel execution of a parallel program depends on • the size of the input data n, and...

Ngày tải lên: 03/07/2014, 16:21

... processes 0 and 1 execute an MPI Recv() operation before an MPI Send() operation. This leads to a deadlock because of mutual waiting: For process 0, the MPI Send() operation can be started not before ... data. The steps to be performed are illustrated in Fig. 5.2 for four processes. For the implementation, we assume that each process provides its local data in an array x and that th...

Ngày tải lên: 03/07/2014, 16:21