The MPI_Barrier-collective operation, as a part of the MPI-1.1
standard, is extremely important for all parallel applications using it.
The latency of this operation increases the application run time and
can not be overlaid. Thus, the whole MPI performance can be decreased
by unsatisfactory barrier latency. The main goals of this work are to
lower the barrier latency for InfiniBand networks by analyzing well
known barrier algorithms with regards to their suitability within
InfiniBand networks, to enhance the barrier operation by utilizing
standard InfiniBand operations as much as possible, and to design a
constant time barrier for InfiniBand with special hardware support.
This partition into three main steps is retained throughout the whole
thesis. The first part evaluates publicly known models and proposes a
new more accurate model (LoP) for InfiniBand. All barrier algorithms are
evaluated within the well known LogP and this new model. Two new
algorithms which promise a better performance have been developed. A
constant time barrier integrated into InfiniBand as well as a cheap
separate barrier network is proposed in the hardware section. All
results have been implemented inside the Open MPI framework. This work
led to three new Open MPI collective modules. The first one implements
different barrier algorithms which are dynamically benchmarked and
selected during the startup phase to maximize the performance. The
second one offers a special barrier implementation for InfiniBand with RDMA
and performs up to 40% better than the best solution that has been
published so far. The third implementation offers a constant time
barrier in a separate network, leveraging commodity components, with a
latency of only 2.5 microseconds. All components have their specialty and can
be used to enhance the barrier performance significantly.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:18332 |
| Date | 01 April 2005 |
| Creators | Hoefler, Torsten |
| Contributors | Mehlan, Torsten, Mietke, Frank, Rehm, Wolfgang, Technische Universität Chemnitz |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | doc-type:masterThesis, info:eu-repo/semantics/masterThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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