Cuda C C++ Objective-C Shell Prolog
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Release Notes for xGPU v0.0.1 ----------------------------- Overview: xGPU is a library for performing the cross-multiplication step of the FX correlator algorithm, which is popular for radio astronomy signal processing. Software Compatibility: The library has been tested under Linux (Ubuntu 10.04 and 10.10) and Mac OS X using release 4.0 of the CUDA toolkit. Default compilation creates a 32-bit binary, so 64-bit systems will require 32-bit c and c++ libraries installed for cross-compilation (gcc and g++ multilib). Hardward Compatibility: For a list of supported devices see, http://www.nvidia.com/object/cuda_learn_products.html While this library will run on pre-Fermi GPUs with appropriate changes to the Makefile, note that the kernels make Fermi-specific optimizations and so will likely lead to sub-standard performance on sm1.x CUDA architectures. Initial tuning has taken place for the Kepler architecture, but this is far from complete. Building the Library: The library, library query tool "xgpuinfo", and the sample program "cuda_correlator" can be built by changing into the src subdirectoy and running "make". $ cd src $ make Currently, a number of sizing parameters must be specified when building the library. Default values of these parameters are specified near the top of src/xgpu_info.h. The default values can be overridden on the make command line to suit your instrument's needs. The options that can be given on the make command line are shown here with there default values. NPOL=2 NSTATION=256 NFREQUENCY=10 NTIME=1000 NTIME_PIPE=100 Note that NTIME_PIPE must be a multiple of 4 and NTIME must be a multiple of NTIME_PIPE. The preprocessor will error out if those two conditions are not met. For example, to compile with NSTATION set to 128 and all other parameters at their default values: $ make NSTATION=128 Installing the Library: The library can be installed by changing into the src subdirectoy and running "make install". By default, this will install xgpuinfo into /usr/local/bin, xgpu.h into /usr/local/include, and libxgpu.so (or libxgpu.dll on Cygwin) to /usr/local/lib. Specifying "prefix=/some/path" on the "make install" command line will install these files into /some/path/bin, /some/path/include, and /some/path/lib instead. $ cd src $ make install # install under /usr/local $ make install prefix=$HOME/local # install under $HOME/local Using the Library: The library can be called from C or C++ code. To use the library, your source files need to #include <xpgu.h> and your executable needs to be linked with libxpgu.so (or libxgpu.dll on Cygwin). On UNIX systems, this usaually means adding "-L/path/to/lib/dir" and "-lxpgu" to the link command line. Please see the comments in xgpu.h as well as the usage in the sample program cuda_correlator.cu for more details on how to use the library. This library has been designed to be interfaced with other parts of an FX correlator pipeline, and so not much can be achieved in isolation. A simple test program "cuda_correlator.cu" is included which performs cross-multiplication on the host and the device and verifies the device obtained the correct answer. The many options regarding number of stations, frequency channels etc. are set in the top of this file. Benchmarking Performance: xGPU includes an additional benchmarking utility: CUBE - CUDA BEnchmarking. This uses C-preprocessor directive to obtain arithmetic throughput and device memory bandwidth performance. To invoke a benchmarking run, one simply has to execute the "bench" script. This will perform four runs of the test. The first two of these are concerned with counting all flops and transfers performed by the kernels, and measuring the time taken for each of these steps. The latter two are concerened with measuring the asynchronous performance of the device<->host transfers. By default the results are printed to stdout, though they are output to file (cube_benchmark.log and cube_benchmark.csv). Acknowledging xGPU: If you find this code useful in your work, please cite: M. A. Clark, P. C. La Plante, and L. J. Greenhill, "Accelerating Radio Astronomy Cross-Correlation with Graphics Processing units", [arXiv:1107.4264 [astro-ph]]. Authors: Michael Clark (NVIDIA) Paul La Plante (Loyola University Maryland) Lincoln Greenhill (Harvard-Smithsonian Center for Astrophysics) David MacMahon (University of California, Berkeley) Ben Barsdell (Harvard-Smithsonian Center for Astrophysics)