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astaroth/src/core/kernels/integration.cu
2020-01-13 21:38:07 +02:00

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/*
Copyright (C) 2014-2020, Johannes Pekkila, Miikka Vaisala.
This file is part of Astaroth.
Astaroth is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
Astaroth is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with Astaroth. If not, see <http://www.gnu.org/licenses/>.
*/
/**
* @file
* \brief Brief info.
*
* Detailed info.
*
*/
#include "common.cuh"
#include "integration.cuh"
#include "src/core/errchk.h"
#include "src/core/math_utils.h"
#include <assert.h>
__constant__ AcMeshInfo d_mesh_info; // Extern in kernels/common.cuh.
static_assert(NUM_VTXBUF_HANDLES > 0, "ERROR: At least one uniform ScalarField must be declared.");
// Device info
#define REGISTERS_PER_THREAD (255)
#define MAX_REGISTERS_PER_BLOCK (65536)
#define MAX_THREADS_PER_BLOCK (1024)
#define WARP_SIZE (32)
#define make_int3(a, b, c) \
(int3) { (int)a, (int)b, (int)c }
template <int step_number>
static __device__ __forceinline__ AcReal
rk3_integrate(const AcReal state_previous, const AcReal state_current, const AcReal rate_of_change,
const AcReal dt)
{
// Williamson (1980)
const AcReal alpha[] = {0, AcReal(.0), AcReal(-5. / 9.), AcReal(-153. / 128.)};
const AcReal beta[] = {0, AcReal(1. / 3.), AcReal(15. / 16.), AcReal(8. / 15.)};
// Note the indexing: +1 to avoid an unnecessary warning about "out-of-bounds"
// access (when accessing beta[step_number-1] even when step_number >= 1)
switch (step_number) {
case 0:
return state_current + beta[step_number + 1] * rate_of_change * dt;
case 1: // Fallthrough
case 2:
return state_current +
beta[step_number + 1] * (alpha[step_number + 1] * (AcReal(1.) / beta[step_number]) *
(state_current - state_previous) +
rate_of_change * dt);
default:
return NAN;
}
}
template <int step_number>
static __device__ __forceinline__ AcReal3
rk3_integrate(const AcReal3 state_previous, const AcReal3 state_current,
const AcReal3 rate_of_change, const AcReal dt)
{
return (AcReal3){
rk3_integrate<step_number>(state_previous.x, state_current.x, rate_of_change.x, dt),
rk3_integrate<step_number>(state_previous.y, state_current.y, rate_of_change.y, dt),
rk3_integrate<step_number>(state_previous.z, state_current.z, rate_of_change.z, dt)};
}
#define rk3(state_previous, state_current, rate_of_change, dt) \
rk3_integrate<step_number>(state_previous, value(state_current), rate_of_change, dt)
static __device__ void
write(AcReal* __restrict__ out[], const int handle, const int idx, const AcReal value)
{
out[handle][idx] = value;
}
static __device__ __forceinline__ void
write(AcReal* __restrict__ out[], const int3 vec, const int idx, const AcReal3 value)
{
write(out, vec.x, idx, value.x);
write(out, vec.y, idx, value.y);
write(out, vec.z, idx, value.z);
}
static __device__ __forceinline__ AcReal
read_out(const int idx, AcReal* __restrict__ field[], const int handle)
{
return field[handle][idx];
}
static __device__ __forceinline__ AcReal3
read_out(const int idx, AcReal* __restrict__ field[], const int3 handle)
{
return (AcReal3){read_out(idx, field, handle.x), read_out(idx, field, handle.y),
read_out(idx, field, handle.z)};
}
#define WRITE_OUT(handle, value) (write(buffer.out, handle, idx, value))
#define READ(handle) (read_data(vertexIdx, globalVertexIdx, buffer.in, handle))
#define READ_OUT(handle) (read_out(idx, buffer.out, handle))
#define GEN_PREPROCESSED_PARAM_BOILERPLATE const int3 &vertexIdx, const int3 &globalVertexIdx
#define GEN_KERNEL_PARAM_BOILERPLATE const int3 start, const int3 end, VertexBufferArray buffer
#define GEN_KERNEL_BUILTIN_VARIABLES_BOILERPLATE() \
const int3 vertexIdx = (int3){threadIdx.x + blockIdx.x * blockDim.x + start.x, \
threadIdx.y + blockIdx.y * blockDim.y + start.y, \
threadIdx.z + blockIdx.z * blockDim.z + start.z}; \
const int3 globalVertexIdx = (int3){d_multigpu_offset.x + vertexIdx.x, \
d_multigpu_offset.y + vertexIdx.y, \
d_multigpu_offset.z + vertexIdx.z}; \
(void)globalVertexIdx; \
if (vertexIdx.x >= end.x || vertexIdx.y >= end.y || vertexIdx.z >= end.z) \
return; \
\
assert(vertexIdx.x < DCONST(AC_nx_max) && vertexIdx.y < DCONST(AC_ny_max) && \
vertexIdx.z < DCONST(AC_nz_max)); \
\
assert(vertexIdx.x >= DCONST(AC_nx_min) && vertexIdx.y >= DCONST(AC_ny_min) && \
vertexIdx.z >= DCONST(AC_nz_min)); \
\
const int idx = IDX(vertexIdx.x, vertexIdx.y, vertexIdx.z);
#define GEN_DEVICE_FUNC_HOOK(identifier) \
template <int step_number> \
AcResult acDeviceKernel_##identifier(const cudaStream_t stream, const int3 start, \
const int3 end, VertexBufferArray vba) \
{ \
\
const dim3 tpb(32, 1, 4); \
\
const int3 n = end - start; \
const dim3 bpg((unsigned int)ceil(n.x / AcReal(tpb.x)), \
(unsigned int)ceil(n.y / AcReal(tpb.y)), \
(unsigned int)ceil(n.z / AcReal(tpb.z))); \
\
identifier<step_number><<<bpg, tpb, 0, stream>>>(start, end, vba); \
ERRCHK_CUDA_KERNEL(); \
\
return AC_SUCCESS; \
}
#include "user_kernels.h"
static dim3 rk3_tpb(32, 1, 4);
AcResult
acKernelAutoOptimizeIntegration(const int3 start, const int3 end, VertexBufferArray vba)
{
// RK3
dim3 best_dims(0, 0, 0);
float best_time = INFINITY;
const int num_iterations = 10;
for (int z = 1; z <= MAX_THREADS_PER_BLOCK; ++z) {
for (int y = 1; y <= MAX_THREADS_PER_BLOCK; ++y) {
for (int x = WARP_SIZE; x <= MAX_THREADS_PER_BLOCK; x += WARP_SIZE) {
if (x > end.x - start.x || y > end.y - start.y || z > end.z - start.z)
break;
if (x * y * z > MAX_THREADS_PER_BLOCK)
break;
if (x * y * z * REGISTERS_PER_THREAD > MAX_REGISTERS_PER_BLOCK)
break;
if (((x * y * z) % WARP_SIZE) != 0)
continue;
const dim3 tpb(x, y, z);
const int3 n = end - start;
const dim3 bpg((unsigned int)ceil(n.x / AcReal(tpb.x)), //
(unsigned int)ceil(n.y / AcReal(tpb.y)), //
(unsigned int)ceil(n.z / AcReal(tpb.z)));
cudaDeviceSynchronize();
if (cudaGetLastError() != cudaSuccess) // resets the error if any
continue;
// printf("(%d, %d, %d)\n", x, y, z);
cudaEvent_t tstart, tstop;
cudaEventCreate(&tstart);
cudaEventCreate(&tstop);
// #ifdef AC_dt
// acDeviceLoadScalarUniform(device, STREAM_DEFAULT, AC_dt, FLT_EPSILON); // TODO
// note, temporarily disabled
/*#else
ERROR("FATAL ERROR: acDeviceAutoOptimize() or
acDeviceIntegrateSubstep() was " "called, but AC_dt was not defined. Either define
it or call the generated " "device function acDeviceKernel_<kernel name> which does
not require the " "timestep to be defined.\n"); #endif*/
cudaEventRecord(tstart); // ---------------------------------------- Timing start
for (int i = 0; i < num_iterations; ++i)
solve<2><<<bpg, tpb>>>(start, end, vba);
cudaEventRecord(tstop); // ----------------------------------------- Timing end
cudaEventSynchronize(tstop);
float milliseconds = 0;
cudaEventElapsedTime(&milliseconds, tstart, tstop);
ERRCHK_CUDA_KERNEL_ALWAYS();
if (milliseconds < best_time) {
best_time = milliseconds;
best_dims = tpb;
}
}
}
}
#if VERBOSE_PRINTING
printf(
"Auto-optimization done. The best threadblock dimensions for rkStep: (%d, %d, %d) %f ms\n",
best_dims.x, best_dims.y, best_dims.z, double(best_time) / num_iterations);
#endif
/*
FILE* fp = fopen("../config/rk3_tbdims.cuh", "w");
ERRCHK(fp);
fprintf(fp, "%d, %d, %d\n", best_dims.x, best_dims.y, best_dims.z);
fclose(fp);
*/
rk3_tpb = best_dims;
return AC_SUCCESS;
}
AcResult
acKernelIntegrateSubstep(const cudaStream_t stream, const int step_number, const int3 start,
const int3 end, VertexBufferArray vba)
{
const dim3 tpb = rk3_tpb;
const int3 n = end - start;
const dim3 bpg((unsigned int)ceil(n.x / AcReal(tpb.x)), //
(unsigned int)ceil(n.y / AcReal(tpb.y)), //
(unsigned int)ceil(n.z / AcReal(tpb.z)));
//#ifdef AC_dt
// acDeviceLoadScalarUniform(device, stream, AC_dt, dt);
/*#else
(void)dt;
ERROR("FATAL ERROR: acDeviceAutoOptimize() or acDeviceIntegrateSubstep() was "
"called, but AC_dt was not defined. Either define it or call the generated "
"device function acDeviceKernel_<kernel name> which does not require the "
"timestep to be defined.\n");
#endif*/
if (step_number == 0)
solve<0><<<bpg, tpb, 0, stream>>>(start, end, vba);
else if (step_number == 1)
solve<1><<<bpg, tpb, 0, stream>>>(start, end, vba);
else
solve<2><<<bpg, tpb, 0, stream>>>(start, end, vba);
ERRCHK_CUDA_KERNEL();
return AC_SUCCESS;
}
static __global__ void
dummy_kernel(void)
{
DCONST((AcIntParam)0);
DCONST((AcInt3Param)0);
DCONST((AcRealParam)0);
DCONST((AcReal3Param)0);
acComplex a = exp(AcReal(1) * acComplex(1, 1) * AcReal(1));
a* a;
}
AcResult
acKernelDummy(void)
{
dummy_kernel<<<1, 1>>>();
ERRCHK_CUDA_KERNEL_ALWAYS();
return AC_SUCCESS;
}