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HPC
Parallelization projects
The world of supercomputers and large clusters is characterized by
the rapid developments in available hardware and software. The speed
of the supercomputers is doubling every three years (Moore's Law), the
amount of memory and disk space also seems to grow exponentionally.
At first sight, one could think that users of supercomputers are able
to tackle larger and larger projects every year.
Alas, this is not always the case. The growth of supercomputer power
is to a large extent possible by architectural changes in the hardware
which necessitate special programming paradigms. At SARA we experienced
a number of supercomputer architectures and we learned how to program
them efficiently by assisting users with optimizing their programs.
Adapting a computer program to a parallel supercomputer
At this moment, parallel computer architectures are common in the world
of supercomputers. It appears that adapting or building computer programs
for these parallel architectures requires special skills. Normally, users
don't have the time to acquire these skills and cannot benefit from
the developments in supercomputer technology. Therefore, SARA decided
to acquire the necessary skills for parallel programming. At this moment,
a number of parallelization projects are successfully ended.
Parallelization of a computer program
In general, the following steps are taken when SARA parallelizes a computer
program:
- Talk with the owner/writer of the program. The purpose of this is to
get an understanding how the program is structured, so that opportunities
for parallelization can be analyzed.
- Decide upon the parallelization method. The choice is dependent
on the program at hand and on the computer architecture, not necessarily
one of SARA's supercomputers
- When appropriate: apply for a grant. For academic users, it is often
possible to apply for a grant from NCF.
(In fact, most of the projects done at SARA were funded by NCF)
- Optimize the serial version of the program. The techniques used
for optimizing serial programs are well-known and quite general usable.
In practice, we see improvements in this fase ranging from 20 % to
a factor of 20
- Parallelize the program
- Run benchmarks and perform scaling experiments
- Produce report
Finished projects
The following projects on parallelizing existing user programs were done:
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The Dutch national supercomputer Huygens, an IBM POWER6 system. |
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