TGQR 2010Q2 Report.pdf - Teragridforum.org

community. User feedback received, from materials science users, for this project also showed
strong support for this project.
The third project involves evaluation and benchmarking of the hybrid (MPI-OpenMP/pthreads)
programming model. Due to the emergence of multi-core processors, hybrid programming, using
MPI tasks and multiple OpenMP threads or pthreads per tasks, is of interest to users. This model
may provide better performance than straight MPI programming. In addition hybrid programming
may allow some simulations that are otherwise not possible due to limited memory available per
core and hence provide a science capability not achievable by straight MPI codes on multi-core
architectures. In order to investigate these issues, AUS staff from PSC, NICS, TACC and SDSC
are comparing performance and usage of codes written in hybrid mode versus straight MPI mode.
The codes being targeted are an astrophysics code, a hybrid benchmarking code, phylogenetics
codes, FFTW, and a Monte Carlo code and work is ongoing. AUS staff are planning to write up
the results comparing straight MPI versus MPI-OpenMP/pthreads performance for TeraGrid user
community. Raghu Reddy (PSC) continued to work with University of Colorado researchers on
measuring the hybrid performance of their code. One of them members of the group will be
presenting the results at TG10. This work also resulted in the following
submission:http://arxiv.org/abs/1003.4322 .
As mentioned earlier the fourth project involves investigating PGAS languages. Progress to-date
includes the implementation of a 2D finite difference kernel in UPC and MPI. Testing of said
kernel demonstrated expected MPI performance and pretty poor UPC performance. Interactions
have began with the Berkeley UPC group, and the TACC project team is still waiting on a
response from them on a few items before they move on to implementation of other kernels. A
Chapel implementation of the same kernel is underway. Benchmarks were also run with MUPC
with similar results.
The fifth project involved developing TAU tutorial and this is done by AUS staff from PSC. This
tutorial and documentation were linked from the AUS projects page (i.e. the same page from
where the other projects of benchmark results and hybrid programming results are published).
The TAU tutorial will give users information about TAU installation on Ranger and Kraken and
other TeraGrid resources, and will be a practical guide for TAU. It will allow users to learn about
the commonly used features of the TAU software tool and will enable users to successfully start
using TAU on TeraGrid resources. Fig 5.1 shows one the images from the tutorial.
Figure 5.1 TAU Startup Screen as Shown in the TAU Tutorial.
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