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dc814f30da
Number of IO MPI tasks can be varied by selecting which
dimensions use parallel IO and which dimensions use Serial send to boss
I/O.
Thus can neck down from, say 1024 nodes = 4x4x8x8 to {1,8,32,64,128,256,1024} nodes
doing the I/O.
Interpolates nicely between ALL nodes write their data, a single boss per time-plane
in processor space [old UKQCD fortran code did this], and a single node doing all I/O.
Not sure I have the transfer sizes big enough and am not overly convinced fstream
is guaranteed to not give buffer inconsistencies unless I set streambuf size to zero.
Practically it has worked on 8 tasks, 2x1x2x2 writing /cloning NERSC configurations
on my MacOS + OpenMPI and Clang environment.
It is VERY easy to switch to pwrite at a later date, and also easy to send x-strips around from
each node in order to gather bigger chunks at the syscall level.
That would push us up to the circa 8x 18*4*8 == 4KB size write chunk, and by taking, say, x/y non
parallel we get to 16MB contiguous chunks written in multi 4KB transactions
per IOnode in 64^3 lattices for configuration I/O.
I suspect this is fine for system performance.
55 lines
1.0 KiB
C++
55 lines
1.0 KiB
C++
//
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// Grid.h
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// simd
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//
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// Created by Peter Boyle on 09/05/2014.
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// Copyright (c) 2014 University of Edinburgh. All rights reserved.
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//
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#ifndef GRID_H
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#define GRID_H
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///////////////////
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// Std C++ dependencies
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///////////////////
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#include <cassert>
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#include <complex>
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#include <vector>
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#include <iostream>
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#include <iomanip>
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#include <random>
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#include <functional>
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdio.h>
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#include <signal.h>
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#include <ctime>
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#include <sys/time.h>
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#include <chrono>
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///////////////////
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// Grid headers
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///////////////////
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#include <serialisation/Serialisation.h>
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#include <Config.h>
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#include <Timer.h>
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#include <Log.h>
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#include <AlignedAllocator.h>
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#include <Simd.h>
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#include <Threads.h>
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#include <Communicator.h>
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#include <Cartesian.h>
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#include <Tensors.h>
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#include <Lattice.h>
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#include <Cshift.h>
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#include <Stencil.h>
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#include <Algorithms.h>
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#include <qcd/QCD.h>
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#include <parallelIO/BinaryIO.h>
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#include <parallelIO/NerscIO.h>
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#include <Init.h>
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#endif
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