"Parallel computational science applications have been
described in terms of computation and communication
patterns. An early taxonomy was the so-called seven dwarfs,
later expanded to 13 (Table 1 below). Description of a parallel
program in terms of patterns has continued along two primary
paths, the Berkeley pattern language and the parallel
patterns developed by Ralph Johnson (one of the gang of
pioneering the description of design patterns). The taxonomy
represented by these patterns describes the operations
performed by typical simulations quite well, and petaFLOPS
rates of computation have been demonstrated across a wide
range of these computational motifs. However, high FLOPS rates
are only part of achieving breakthrough science using
computation. High I/O performance is critical from a
performance and productivity perspective, to support
interpretation of computational results and operation of these
codes at fidelities enabled by extreme-scale computers. Codes
across the range of computational motifs are finding it
difficult to perform I/O on s petascale architectures, and
this I/O problem may limit those ability to achieve exascale
performance.
Although high-level I/O libraries have made an important
contribution to supporting large parallel applications, they
do not always attain a high percentage of peak performance
when used from these applications. The reasons, among others,
have been that (1) the underlying models, formats, and APIs in
storage software did not explicitly consider parallelism in
their original designs, (2) the parallelism subsequently
introduced has been incremental and has often been driven to
work around limitations of interfaces and underlying software
(e.g., working around a specific file system performance bug),
and (3) many more applications require, for scalability and
algorithmic reasons, much more sophisticated data structures
than what the original designs had incorporated (e.g.,
adaptive meshes, irregular datasets).
http://cucis.ece.northwestern.edu/projects/DAMSEL/
https://www.mcs.anl.gov/project/damsel-data-model-storage-library-exasxale-science
https://www.mcs.anl.gov/group/data-intensive-science
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