51,167 research outputs found
GPU peer-to-peer techniques applied to a cluster interconnect
Modern GPUs support special protocols to exchange data directly across the
PCI Express bus. While these protocols could be used to reduce GPU data
transmission times, basically by avoiding staging to host memory, they require
specific hardware features which are not available on current generation
network adapters. In this paper we describe the architectural modifications
required to implement peer-to-peer access to NVIDIA Fermi- and Kepler-class
GPUs on an FPGA-based cluster interconnect. Besides, the current software
implementation, which integrates this feature by minimally extending the RDMA
programming model, is discussed, as well as some issues raised while employing
it in a higher level API like MPI. Finally, the current limits of the technique
are studied by analyzing the performance improvements on low-level benchmarks
and on two GPU-accelerated applications, showing when and how they seem to
benefit from the GPU peer-to-peer method.Comment: paper accepted to CASS 201
Control System for the LEDA 6.7-MeV Proton Beam Halo Experiment
Measurement of high-power proton beam-halo formation is the ongoing
scientific experiment for the Low Energy Demonstration Accelerator (LEDA)
facility. To attain this measurement goal, a 52-magnet beam line containing
several types of beam diagnostic instrumentation is being installed. The
Experimental Physics and Industrial Control System (EPICS) and commercial
software applications are presently being integrated to provide a real-time,
synchronous data acquisition and control system. This system is comprised of
magnet control, vacuum control, motor control, data acquisition, and data
analysis. Unique requirements led to the development and integration of
customized software and hardware. EPICS real-time databases, Interactive Data
Language (IDL) programs, LabVIEW Virtual Instruments (VI), and State Notation
Language (SNL) sequences are hosted on VXI, PC, and UNIX-based platforms which
interact using the EPICS Channel Access (CA) communication protocol.
Acquisition and control hardware technology ranges from DSP-based diagnostic
instrumentation to the PLC-controlled vacuum system. This paper describes the
control system hardware and software design, and implementation.Comment: LINAC2000 Conference, 4 pg
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