牛津大学HPC的技术介绍.pdf

A Dynamic World, what can Grids do for Multi-Core computing? Daniel Goodman, Anne Trefethen and Douglas Creager Daniel.Goodman@oerc.ox.ac.uk What we will cover • Why we think that cluster programming models are not always enough for multi-core computing • Why we think that Grid programming models are for many cases more appropriate • Quick look over some programming models that have worked well in grids and we believe could be constructive in multi- core environments • Look at where some of these ideas are reappearing in models for multi-core computing Assumptions when programming clusters • Node within an allocated set are all homogenous, both in terms of the configuration, and the loads being placed on them • Once nodes have been allocated to a process they will not be used by any other user process until the first finishes Assumptions when programming clusters • Outside of very tightly coupled tasks on very large numbers of processors, the noise caused by other background tasks running on the node has a minimal effect on user processes • Because nodes will run the same background tasks, large supercomputers able to handle the problem of background tasks through centralised control of when such tasks execute Models for Programming Clusters • Message passing, MPI • Shared memory, OpenMP • Embarrassingly parallel batch jobs Properties of Multi-core systems • Cores will be shared with a wide range of other applications dynamically • Load can no l