opencl_example.cpp
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//===--- opencl_example.cpp - Example of using Acxxel with OpenCL ---------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
///
/// This file is an example of using OpenCL with Acxxel.
///
//===----------------------------------------------------------------------===//
#include "acxxel.h"
#include <array>
#include <cstdio>
#include <cstring>
static const char *SaxpyKernelSource = R"(
__kernel void saxpyKernel(float A, __global float *X, __global float *Y, int N) {
int I = get_global_id(0);
if (I < N)
X[I] = A * X[I] + Y[I];
}
)";
template <size_t N>
void saxpy(float A, std::array<float, N> &X, const std::array<float, N> &Y) {
acxxel::Platform *OpenCL = acxxel::getOpenCLPlatform().getValue();
acxxel::Stream Stream = OpenCL->createStream().takeValue();
auto DeviceX = OpenCL->mallocD<float>(N).takeValue();
auto DeviceY = OpenCL->mallocD<float>(N).takeValue();
Stream.syncCopyHToD(X, DeviceX).syncCopyHToD(Y, DeviceY);
acxxel::Program Program =
OpenCL
->createProgramFromSource(acxxel::Span<const char>(
SaxpyKernelSource, std::strlen(SaxpyKernelSource)))
.takeValue();
acxxel::Kernel Kernel = Program.createKernel("saxpyKernel").takeValue();
float *RawX = static_cast<float *>(DeviceX);
float *RawY = static_cast<float *>(DeviceY);
int IntLength = N;
void *Arguments[] = {&A, &RawX, &RawY, &IntLength};
size_t ArgumentSizes[] = {sizeof(float), sizeof(float *), sizeof(float *),
sizeof(int)};
acxxel::Status Status =
Stream.asyncKernelLaunch(Kernel, N, Arguments, ArgumentSizes)
.syncCopyDToH(DeviceX, X)
.sync();
if (Status.isError()) {
std::fprintf(stderr, "Error during saxpy: %s\n",
Status.getMessage().c_str());
std::exit(EXIT_FAILURE);
}
}
int main() {
float A = 2.f;
std::array<float, 3> X{{0.f, 1.f, 2.f}};
std::array<float, 3> Y{{3.f, 4.f, 5.f}};
std::array<float, 3> Expected{{3.f, 6.f, 9.f}};
saxpy(A, X, Y);
for (int I = 0; I < 3; ++I)
if (X[I] != Expected[I]) {
std::fprintf(stderr, "Mismatch at position %d, %f != %f\n", I, X[I],
Expected[I]);
std::exit(EXIT_FAILURE);
}
}