f9ae670d05
This is a little hello world for OpenCL. Change-Id: I9502407dab75694a19e97832bcfe33f47cbd97e9 Reviewed-on: https://skia-review.googlesource.com/136223 Commit-Queue: Allan MacKinnon <allanmac@google.com> Reviewed-by: Allan MacKinnon <allanmac@google.com>
119 lines
4.3 KiB
C++
119 lines
4.3 KiB
C++
/*
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* Copyright 2018 Google Inc.
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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// This is a simple OpenCL Hello World that tests you have a functioning OpenCL setup.
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#include <CL/cl.hpp>
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#include <initializer_list>
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extern "C" {
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#include "cl/assert_cl.h" // for cl(), cl_ok() macros
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#include "cl/find_cl.h" // for clFindIdsByName
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}
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int main(int argc, char** argv) {
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// Find any OpenCL platform+device with these substrings.
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const char* platform_match = argc > 1 ? argv[1] : "";
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const char* device_match = argc > 2 ? argv[2] : "";
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cl_platform_id platform_id;
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cl_device_id device_id;
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char device_name[256];
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size_t device_name_len;
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// clFindIdsByName will narrate what it's doing when this is set.
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bool verbose = true;
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// The cl() macro prepends cl to its argument, calls it, and asserts that it succeeded,
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// printing out the file, line, and somewhat readable version of the error code on failure.
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//
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// It's generally used to call OpenCL APIs, but here we've written clFindIdsByName to match
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// the convention, as its error conditions are just going to be passed along from OpenCL.
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cl(FindIdsByName(platform_match, device_match,
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&platform_id, &device_id,
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sizeof(device_name), device_name, &device_name_len,
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verbose));
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printf("picked %.*s\n", (int)device_name_len, device_name);
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// Allan's code is all C using OpenCL's C API,
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// but we can mix that freely with the C++ API found in cl.hpp.
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// cl_ok() comes in handy here, which is cl() without the extra cl- prefix.
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cl::Device device(device_id);
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std::string name,
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vendor,
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extensions;
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cl_ok(device.getInfo(CL_DEVICE_NAME, &name));
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cl_ok(device.getInfo(CL_DEVICE_VENDOR, &vendor));
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cl_ok(device.getInfo(CL_DEVICE_EXTENSIONS, &extensions));
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printf("name %s, vendor %s, extensions:\n%s\n",
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name.c_str(), vendor.c_str(), extensions.c_str());
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std::vector<cl::Device> devices = { device };
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// Some APIs can't return their cl_int error but might still fail,
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// so they take a pointer. cl_ok() is really handy here too.
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cl_int ok;
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cl::Context ctx(devices,
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nullptr/*optional cl_context_properties*/,
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nullptr/*optional error reporting callback*/,
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nullptr/*context arguement for error reporting callback*/,
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&ok);
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cl_ok(ok);
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cl::Program program(ctx,
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"__kernel void mul(__global const float* a, "
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" __global const float* b, "
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" __global float* dst) {"
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" int i = get_global_id(0); "
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" dst[i] = a[i] * b[i]; "
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"} ",
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/*and build now*/true,
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&ok);
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cl_ok(ok);
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std::vector<float> a,b,p;
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for (int i = 0; i < 1000; i++) {
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a.push_back(+i);
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b.push_back(-i);
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p.push_back( 0);
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}
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cl::Buffer A(ctx, CL_MEM_READ_ONLY | CL_MEM_COPY_HOST_PTR , sizeof(float)*a.size(), a.data()),
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B(ctx, CL_MEM_READ_ONLY | CL_MEM_COPY_HOST_PTR , sizeof(float)*b.size(), b.data()),
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P(ctx, CL_MEM_WRITE_ONLY| CL_MEM_HOST_READ_ONLY, sizeof(float)*p.size());
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cl::Kernel mul(program, "mul", &ok);
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cl_ok(ok);
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cl_ok(mul.setArg(0, A));
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cl_ok(mul.setArg(1, B));
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cl_ok(mul.setArg(2, P));
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cl::CommandQueue queue(ctx, device);
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cl_ok(queue.enqueueNDRangeKernel(mul, cl::NDRange(0) /*offset*/
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, cl::NDRange(1000) /*size*/));
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cl_ok(queue.enqueueReadBuffer(P, true/*block until read is done*/
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, 0 /*offset in bytes*/
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, sizeof(float)*p.size() /*size in bytes*/
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, p.data()));
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for (int i = 0; i < 1000; i++) {
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if (p[i] != a[i]*b[i]) {
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return 1;
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}
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}
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printf("OpenCL sez: %g x %g = %g\n", a[42], b[42], p[42]);
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return 0;
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}
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