forked from lijiext/lammps
135 lines
5.2 KiB
Plaintext
135 lines
5.2 KiB
Plaintext
This directory has source files to build a library that LAMMPS
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links against when using the GPU package.
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When you are done building this library, two files should
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exist in this directory:
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libgpu.a the library LAMMPS will link against
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Makefile.lammps settings the LAMMPS Makefile will import
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The latter file will have settings like this (can be omitted if blank):
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gpu_SYSINC =
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gpu_SYSLIB = -lcudart -lcuda
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gpu_SYSPATH = -L/usr/local/cuda/lib64
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SYSINC is for settings needed to compile LAMMPS source files
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SYSLIB is for additional system libraries needed by this package
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SYSPATH is the path(s) to where those libraries are
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You must insure these settings are correct for your system, else
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the LAMMPS build will likely fail.
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-------------------------------------------------------------------------
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Contributing authors: Mike Brown (ORNL), brownw@ornl.gov
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Peng Wang (Nvidia), penwang@nvidia.com
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Inderaj Bains (NVIDIA), ibains@nvidia.com
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Paul Crozier (SNL), pscrozi@sandia.gov
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-------------------------------------------------------------------------
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GENERAL NOTES
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This library, libgpu.a, provides routines for GPU acceleration
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of LAMMPS pair styles. Compilation of this library requires
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installing the CUDA GPU driver and CUDA toolkit for your operating
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system. In addition to the LAMMPS library, the binary nvc_get_devices
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will also be built. This can be used to query the names and
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properties of GPU devices on your system. A Makefile for OpenCL
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compilation is provided, but support for OpenCL use is not currently
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provided by the developers.
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NOTE: Installation of the CUDA SDK is not required.
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Current pair styles supporting GPU acceleration:
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1. lj/cut
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2. lj96/cut
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3. lj/expand
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4. lj/cut/coul/cut
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5. lj/cut/coul/long
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6. lj/charmm/coul/long
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7. morse
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8. cg/cmm
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9. cg/cmm/coul/long
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10. coul/long
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11. gayberne
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12. pppm
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MULTIPLE LAMMPS PROCESSES
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Multiple LAMMPS MPI processes can share GPUs on the system, but multiple
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GPUs cannot be utilized by a single MPI process. In many cases, the
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best performance will be obtained by running as many MPI processes as
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CPU cores available with the condition that the number of MPI processes
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is an integer multiple of the number of GPUs being used. See the
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LAMMPS user manual for details on running with GPU acceleration.
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BUILDING AND PRECISION MODES
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To build, edit the CUDA_ARCH, CUDA_PRECISION, CUDA_HOME variables in one of
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the Makefiles. CUDA_ARCH should be set based on the compute capability of
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your GPU. This can be verified by running the nvc_get_devices executable after
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the build is complete. Additionally, the GPU package must be installed and
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compiled for LAMMPS. This may require editing the gpu_SYSPATH variable in the
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LAMMPS makefile.
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Please note that the GPU library accesses the CUDA driver library directly,
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so it needs to be linked not only to the CUDA runtime library (libcudart.so)
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that ships with the CUDA toolkit, but also with the CUDA driver library
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(libcuda.so) that ships with the Nvidia driver. If you are compiling LAMMPS
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on the head node of a GPU cluster, this library may not be installed,
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so you may need to copy it over from one of the compute nodes (best into
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this directory).
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The gpu library supports 3 precision modes as determined by
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the CUDA_PRECISION variable:
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CUDA_PREC = -D_SINGLE_SINGLE # Single precision for all calculations
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CUDA_PREC = -D_DOUBLE_DOUBLE # Double precision for all calculations
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CUDA_PREC = -D_SINGLE_DOUBLE # Accumulation of forces, etc. in double
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NOTE: PPPM acceleration can only be run on GPUs with compute capability>=1.1.
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You will get the error "GPU library not compiled for this accelerator."
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when attempting to run PPPM on a GPU with compute capability 1.0.
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NOTE: Double precision is only supported on certain GPUs (with
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compute capability>=1.3). If you compile the GPU library for
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a GPU with compute capability 1.1 and 1.2, then only single
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precistion FFTs are supported, i.e. LAMMPS has to be compiled
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with -DFFT_SINGLE. For details on configuring FFT support in
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LAMMPS, see http://lammps.sandia.gov/doc/Section_start.html#2_2_4
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NOTE: For graphics cards with compute capability>=1.3 (e.g. Tesla C1060),
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make sure that -arch=sm_13 is set on the CUDA_ARCH line.
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NOTE: For newer graphics card (a.k.a. "Fermi", e.g. Tesla C2050), make
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sure that either -arch=sm_20 or -arch=sm_21 is set on the
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CUDA_ARCH line, depending on hardware and CUDA toolkit version.
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NOTE: The gayberne/gpu pair style will only be installed if the ASPHERE
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package has been installed.
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NOTE: The cg/cmm/gpu and cg/cmm/coul/long/gpu pair styles will only be
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installed if the USER-CG-CMM package has been installed.
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NOTE: The lj/cut/coul/long/gpu, cg/cmm/coul/long/gpu, coul/long/gpu,
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lj/charmm/coul/long/gpu and pppm/gpu styles will only be installed
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if the KSPACE package has been installed.
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EXAMPLE BUILD PROCESS
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cd ~/lammps/lib/gpu
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emacs Makefile.linux
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make -f Makefile.linux
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./nvc_get_devices
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cd ../../src
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emacs ./MAKE/Makefile.linux
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make yes-asphere
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make yes-kspace
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make yes-gpu
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make linux
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