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2015
Springer

On the Impact of Synchronizing Clocks and Processes on Benchmarking MPI Collectives

4 years 2 months ago
On the Impact of Synchronizing Clocks and Processes on Benchmarking MPI Collectives
We consider the problem of accurately measuring the time to complete an MPI collective operation, as the result strongly depends on how the time is measured. Our goal is to develop an experimental method that allows for reproducible measurements of MPI collectives. When executing large parallel codes, MPI processes are often skewed in time when entering a collective operation. However, to obtain reproducible measurements, it is a common approach to synchronize all processes before they call the MPI collective operation. We therefore take a closer look at two commonly used process synchronization schemes: (1) relying on MPI_Barrier or (2) applying a window-based scheme using a common global time. We analyze both schemes experimentally and show the strengths and weaknesses of each approach. As window-based schemes require the notion of global time, we thoroughly evaluate different clock synchronization algorithms in various experiments. We also propose a novel clock synchronization alg...
Added 16 Apr 2016
Updated 16 Apr 2016
Type Journal
Year 2015
Where PVM
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