gnss-sdr/src/algorithms/tracking/libs/cuda_multicorrelator.cu

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/*!
* \file cuda_multicorrelator.cu
* \brief High optimized CUDA GPU vector multiTAP correlator class
* \authors <ul>
* <li> Javier Arribas, 2015. jarribas(at)cttc.es
* </ul>
*
* Class that implements a high optimized vector multiTAP correlator class for NVIDIA CUDA GPUs
*
* -------------------------------------------------------------------------
*
* Copyright (C) 2010-2015 (see AUTHORS file for a list of contributors)
*
* GNSS-SDR is a software defined Global Navigation
* Satellite Systems receiver
*
* This file is part of GNSS-SDR.
*
* GNSS-SDR 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.
*
* GNSS-SDR 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 GNSS-SDR. If not, see <http://www.gnu.org/licenses/>.
*
* -------------------------------------------------------------------------
*/
///////////////////////////////////////////////////////////////////////////////
// On G80-class hardware 24-bit multiplication takes 4 clocks per warp
// (the same as for floating point multiplication and addition),
// whereas full 32-bit multiplication takes 16 clocks per warp.
// So if integer multiplication operands are guaranteed to fit into 24 bits
// (always lie withtin [-8M, 8M - 1] range in signed case),
// explicit 24-bit multiplication is preferred for performance.
///////////////////////////////////////////////////////////////////////////////
#define IMUL(a, b) __mul24(a, b)
#include "cuda_multicorrelator.h"
#include <stdio.h>
// For the CUDA runtime routines (prefixed with "cuda_")
#include <cuda_runtime.h>
// helper functions and utilities to work with CUDA
#include <helper_cuda.h>
#include <helper_functions.h>
#define ACCUM_N 1024
///////////////////////////////////////////////////////////////////////////////
// Calculate scalar products of VectorN vectors of ElementN elements on GPU
// Parameters restrictions:
// 1) ElementN is strongly preferred to be a multiple of warp size to
// meet alignment constraints of memory coalescing.
// 2) ACCUM_N must be a power of two.
///////////////////////////////////////////////////////////////////////////////
__global__ void scalarProdGPUCPXxN_shifts(
GPU_Complex *d_corr_out,
GPU_Complex *d_sig_in,
GPU_Complex *d_local_codes_in,
int *d_shifts_samples,
int vectorN,
int elementN
)
{
//Accumulators cache
__shared__ GPU_Complex accumResult[ACCUM_N];
////////////////////////////////////////////////////////////////////////////
// Cycle through every pair of vectors,
// taking into account that vector counts can be different
// from total number of thread blocks
////////////////////////////////////////////////////////////////////////////
for (int vec = blockIdx.x; vec < vectorN; vec += gridDim.x)
{
int vectorBase = IMUL(elementN, vec);
int vectorEnd = vectorBase + elementN;
////////////////////////////////////////////////////////////////////////
// Each accumulator cycles through vectors with
// stride equal to number of total number of accumulators ACCUM_N
// At this stage ACCUM_N is only preferred be a multiple of warp size
// to meet memory coalescing alignment constraints.
////////////////////////////////////////////////////////////////////////
for (int iAccum = threadIdx.x; iAccum < ACCUM_N; iAccum += blockDim.x)
{
GPU_Complex sum = GPU_Complex(0,0);
for (int pos = vectorBase + iAccum; pos < vectorEnd; pos += ACCUM_N)
{
//sum = sum + d_sig_in[pos-vectorBase] * d_nco_in[pos-vectorBase] * d_local_codes_in[pos];
//sum = sum + d_sig_in[pos-vectorBase] * d_local_codes_in[pos];
sum.multiply_acc(d_sig_in[pos-vectorBase],d_local_codes_in[pos-vectorBase+d_shifts_samples[vec]]);
}
accumResult[iAccum] = sum;
}
////////////////////////////////////////////////////////////////////////
// Perform tree-like reduction of accumulators' results.
// ACCUM_N has to be power of two at this stage
////////////////////////////////////////////////////////////////////////
for (int stride = ACCUM_N / 2; stride > 0; stride >>= 1)
{
__syncthreads();
for (int iAccum = threadIdx.x; iAccum < stride; iAccum += blockDim.x)
{
accumResult[iAccum] += accumResult[stride + iAccum];
}
}
if (threadIdx.x == 0)
{
d_corr_out[vec] = accumResult[0];
}
}
}
__global__ void scalarProdGPUCPXxN(
GPU_Complex *d_corr_out,
GPU_Complex *d_sig_in,
GPU_Complex *d_local_codes_in,
int vectorN,
int elementN
)
{
//Accumulators cache
__shared__ GPU_Complex accumResult[ACCUM_N];
////////////////////////////////////////////////////////////////////////////
// Cycle through every pair of vectors,
// taking into account that vector counts can be different
// from total number of thread blocks
////////////////////////////////////////////////////////////////////////////
for (int vec = blockIdx.x; vec < vectorN; vec += gridDim.x)
{
int vectorBase = IMUL(elementN, vec);
int vectorEnd = vectorBase + elementN;
////////////////////////////////////////////////////////////////////////
// Each accumulator cycles through vectors with
// stride equal to number of total number of accumulators ACCUM_N
// At this stage ACCUM_N is only preferred be a multiple of warp size
// to meet memory coalescing alignment constraints.
////////////////////////////////////////////////////////////////////////
for (int iAccum = threadIdx.x; iAccum < ACCUM_N; iAccum += blockDim.x)
{
GPU_Complex sum = GPU_Complex(0,0);
for (int pos = vectorBase + iAccum; pos < vectorEnd; pos += ACCUM_N)
{
//sum = sum + d_sig_in[pos-vectorBase] * d_nco_in[pos-vectorBase] * d_local_codes_in[pos];
//sum = sum + d_sig_in[pos-vectorBase] * d_local_codes_in[pos];
sum.multiply_acc(d_sig_in[pos-vectorBase],d_local_codes_in[pos]);
}
accumResult[iAccum] = sum;
}
////////////////////////////////////////////////////////////////////////
// Perform tree-like reduction of accumulators' results.
// ACCUM_N has to be power of two at this stage
////////////////////////////////////////////////////////////////////////
for (int stride = ACCUM_N / 2; stride > 0; stride >>= 1)
{
__syncthreads();
for (int iAccum = threadIdx.x; iAccum < stride; iAccum += blockDim.x)
{
accumResult[iAccum] += accumResult[stride + iAccum];
}
}
if (threadIdx.x == 0)
{
d_corr_out[vec] = accumResult[0];
}
}
}
//*********** CUDA processing **************
// Treads: a minimal parallel execution code on GPU
// Blocks: a set of N threads
/**
* CUDA Kernel Device code
*
* Computes the vectorial product of A and B into C. The 3 vectors have the same
* number of elements numElements.
*/
__global__ void CUDA_32fc_x2_multiply_32fc( GPU_Complex *A, GPU_Complex *B, GPU_Complex *C, int numElements)
{
int i = blockDim.x * blockIdx.x + threadIdx.x;
if (i < numElements)
{
C[i] = A[i] * B[i];
}
}
/**
* CUDA Kernel Device code
*
* Computes the carrier Doppler wipe-off by integrating the NCO in the CUDA kernel
*/
__global__ void
CUDA_32fc_Doppler_wipeoff( GPU_Complex *sig_out, GPU_Complex *sig_in, float rem_carrier_phase_in_rad, float phase_step_rad, int numElements)
{
//*** NCO CPU code (GNURadio FXP NCO)
//float sin_f, cos_f;
//float phase_step_rad = static_cast<float>(2 * GALILEO_PI) * d_carrier_doppler_hz / static_cast<float>(d_fs_in);
//int phase_step_rad_i = gr::fxpt::float_to_fixed(phase_step_rad);
//int phase_rad_i = gr::fxpt::float_to_fixed(d_rem_carr_phase_rad);
//
//for(int i = 0; i < d_current_prn_length_samples; i++)
// {
// gr::fxpt::sincos(phase_rad_i, &sin_f, &cos_f);
// d_carr_sign[i] = std::complex<float>(cos_f, -sin_f);
// phase_rad_i += phase_step_rad_i;
// }
// CUDA version of floating point NCO and vector dot product integrated
int i = blockDim.x * blockIdx.x + threadIdx.x;
float sin;
float cos;
if (i < numElements)
{
__sincosf(rem_carrier_phase_in_rad + i*phase_step_rad, &sin, &cos);
sig_out[i] = sig_in[i] * GPU_Complex(cos,-sin);
}
}
/**
* CUDA Kernel Device code
*
* Computes the vectorial product of A and B into C. The 3 vectors have the same
* number of elements numElements.
*/
__global__ void
CUDA_32fc_x2_add_32fc( GPU_Complex *A, GPU_Complex *B, GPU_Complex *C, int numElements)
{
int i = blockDim.x * blockIdx.x + threadIdx.x;
if (i < numElements)
{
C[i] = A[i] * B[i];
}
}
bool cuda_multicorrelator::init_cuda(const int argc, const char **argv, int signal_length_samples, int *shifts_samples, int n_correlators)
{
// use command-line specified CUDA device, otherwise use device with highest Gflops/s
findCudaDevice(argc, (const char **)argv);
cudaDeviceProp prop;
int whichDevice;
cudaGetDevice( &whichDevice );
cudaGetDeviceProperties( &prop, whichDevice );
//debug code
if (prop.canMapHostMemory != 1) {
printf( "Device can not map memory.\n" );
}
printf("L2 Cache size= %u \n",prop.l2CacheSize);
printf("maxThreadsPerBlock= %u \n",prop.maxThreadsPerBlock);
printf("maxGridSize= %i \n",prop.maxGridSize[0]);
printf("sharedMemPerBlock= %lu \n",prop.sharedMemPerBlock);
printf("deviceOverlap= %i \n",prop.deviceOverlap);
//end debug code
//checkCudaErrors(cudaFuncSetCacheConfig(CUDA_32fc_x2_multiply_x2_dot_prod_32fc_, cudaFuncCachePreferShared));
// ALLOCATE GPU MEMORY FOR INPUT/OUTPUT and INTERNAL vectors
size_t size = signal_length_samples * sizeof(GPU_Complex);
checkCudaErrors(cudaMalloc((void **)&d_sig_in, size));
//checkCudaErrors(cudaMalloc((void **)&d_nco_in, size));
checkCudaErrors(cudaMalloc((void **)&d_sig_doppler_wiped, size));
// old version: all local codes are independent vectors
//checkCudaErrors(cudaMalloc((void **)&d_local_codes_in, size*n_correlators));
// new version: only one vector with extra samples to shift the local code for the correlator set
// Required: The last correlator tap in d_shifts_samples has the largest sample shift
checkCudaErrors(cudaMalloc((void **)&d_local_codes_in, size+sizeof(GPU_Complex)*shifts_samples[n_correlators-1]));
checkCudaErrors(cudaMalloc((void **)&d_shifts_samples, size+sizeof(int)*n_correlators));
//scalars
checkCudaErrors(cudaMalloc((void **)&d_corr_out, sizeof(std::complex<float>)*n_correlators));
// Launch the Vector Add CUDA Kernel
threadsPerBlock = 256;
blocksPerGrid =(int)(signal_length_samples+threadsPerBlock-1)/threadsPerBlock;
return true;
}
bool cuda_multicorrelator::Carrier_wipeoff_multicorrelator_cuda(
std::complex<float>* corr_out,
const std::complex<float>* sig_in,
const std::complex<float>* local_codes_in,
float rem_carrier_phase_in_rad,
float phase_step_rad,
const int *shifts_samples,
int signal_length_samples,
int n_correlators)
{
cudaStream_t stream1;
cudaStream_t stream2;
cudaStreamCreate ( &stream1) ;
cudaStreamCreate ( &stream2) ;
size_t memSize = signal_length_samples * sizeof(std::complex<float>);
// input signal CPU -> GPU copy memory
checkCudaErrors(cudaMemcpyAsync(d_sig_in, sig_in, memSize,
cudaMemcpyHostToDevice, stream1));
//***** NOTICE: NCO is computed on-the-fly, not need to copy NCO into GPU! ****
//checkCudaErrors(cudaMemcpyAsync(d_nco_in, nco_in, memSize,
// cudaMemcpyHostToDevice, stream1));
// old version: all local codes are independent vectors
//checkCudaErrors(cudaMemcpyAsync(d_local_codes_in, local_codes_in, memSize*n_correlators,
// cudaMemcpyHostToDevice, stream2));
// new version: only one vector with extra samples to shift the local code for the correlator set
// Required: The last correlator tap in d_shifts_samples has the largest sample shift
// local code CPU -> GPU copy memory
checkCudaErrors(cudaMemcpyAsync(d_local_codes_in, local_codes_in, memSize+sizeof(std::complex<float>)*shifts_samples[n_correlators-1],
cudaMemcpyHostToDevice, stream2));
// Correlator shifts vector CPU -> GPU copy memory
checkCudaErrors(cudaMemcpyAsync(d_shifts_samples, shifts_samples, sizeof(int)*n_correlators,
cudaMemcpyHostToDevice, stream2));
//Launch carrier wipe-off kernel here, while local codes are being copied to GPU!
checkCudaErrors(cudaStreamSynchronize(stream1));
CUDA_32fc_Doppler_wipeoff<<<blocksPerGrid, threadsPerBlock,0, stream1>>>(d_sig_doppler_wiped, d_sig_in,rem_carrier_phase_in_rad,phase_step_rad, signal_length_samples);
//printf("CUDA kernel launch with %d blocks of %d threads\n", blocksPerGrid, threadsPerBlock);
//wait for Doppler wipeoff end...
checkCudaErrors(cudaDeviceSynchronize());
//old
// scalarProdGPUCPXxN<<<blocksPerGrid, threadsPerBlock,0 ,stream2>>>(
// d_corr_out,
// d_sig_doppler_wiped,
// d_local_codes_in,
// 3,
// signal_length_samples
// );
//new
//launch the multitap correlator
scalarProdGPUCPXxN_shifts<<<blocksPerGrid, threadsPerBlock,0 ,stream2>>>(
d_corr_out,
d_sig_doppler_wiped,
d_local_codes_in,
d_shifts_samples,
n_correlators,
signal_length_samples
);
checkCudaErrors(cudaGetLastError());
//wait for correlators end...
checkCudaErrors(cudaDeviceSynchronize());
// Copy the device result vector in device memory to the host result vector
// in host memory.
//scalar products (correlators outputs)
checkCudaErrors(cudaMemcpyAsync(corr_out, d_corr_out, sizeof(std::complex<float>)*n_correlators,
cudaMemcpyDeviceToHost, 0));
cudaStreamDestroy(stream1) ;
cudaStreamDestroy(stream2) ;
return true;
}
bool cuda_multicorrelator::free_cuda()
{
// Free device global memory
cudaFree(d_sig_in);
//cudaFree(d_nco_in);
cudaFree(d_local_codes_in);
cudaFree(d_corr_out);
// Reset the device and exit
// cudaDeviceReset causes the driver to clean up all state. While
// not mandatory in normal operation, it is good practice. It is also
// needed to ensure correct operation when the application is being
// profiled. Calling cudaDeviceReset causes all profile data to be
// flushed before the application exits
checkCudaErrors(cudaDeviceReset());
return true;
}