Fixes #680: Added the matrixMulCUBLAS (modified) CUDA sample to the…

… examples

examples/CMakeLists.txt

@@ -56,6 +56,10 @@ link_libraries(cuda-api-wrappers::runtime-and-driver)
 
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY "bin")
 add_executable(vectorAdd modified_cuda_samples/vectorAdd/vectorAdd.cu)
+if (TARGET CUDA::cublas)
+	add_executable(matrixMulCUBLAS modified_cuda_samples/matrixMulCUBLAS/matrixMulCUBLAS.cpp)
+	target_link_libraries(matrixMulCUBLAS CUDA::cublas)
+endif()
 add_executable(vectorAdd_unique_regions modified_cuda_samples/vectorAdd_unique_regions/vectorAdd_unique_regions.cu)
 add_executable(vectorAddMapped modified_cuda_samples/vectorAddMapped/vectorAddMapped.cu)
 add_executable(vectorAddManaged modified_cuda_samples/vectorAddManaged/vectorAddManaged.cu)

examples/modified_cuda_samples/matrixMulCUBLAS/matrixMulCUBLAS.cpp

@@ -0,0 +1,289 @@
+/*
+ * Original code Copyright (c) 2022, NVIDIA CORPORATION. All rights reserved.
+ * Modifications Copyright (c) 2024, Eyal Rozenberg <[email protected]>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *  * Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ *  * Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in the
+ *    documentation and/or other materials provided with the distribution.
+ *  * Neither the name of NVIDIA CORPORATION nor the names of its
+ *    contributors may be used to endorse or promote products derived
+ *    from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+* Matrix multiplication: C = A * B.
+* Host code.
+*
+* This sample implements matrix multiplication as described in Chapter 3
+* of the programming guide and uses the CUBLAS library to demonstrate
+* the best performance.
+
+* SOME PRECAUTIONS:
+* IF WE WANT TO CALCULATE ROW-MAJOR MATRIX MULTIPLY C = A * B,
+* WE JUST NEED CALL CUBLAS API IN A REVERSE ORDER: cublasSegemm(B, A)!
+* The reason is explained as follows:
+
+* CUBLAS library uses column-major storage, but C/C++ use row-major storage.
+* When passing the matrix pointer to CUBLAS, the memory layout alters from
+* row-major to column-major, which is equivalent to an implicit transpose.
+
+* In the case of row-major C/C++ matrix A, B, and a simple matrix multiplication
+* C = A * B, we can't use the input order like cublasSgemm(A, B)  because of
+* implicit transpose. The actual result of cublasSegemm(A, B) is A(T) * B(T).
+* If col(A(T)) != row(B(T)), equal to row(A) != col(B), A(T) and B(T) are not
+* multipliable. Moreover, even if A(T) and B(T) are multipliable, the result C
+* is a column-based cublas matrix, which means C(T) in C/C++, we need extra
+* transpose code to convert it to a row-based C/C++ matrix.
+
+* To solve the problem, let's consider our desired result C, a row-major matrix.
+* In cublas format, it is C(T) actually (because of the implicit transpose).
+* C = A * B, so C(T) = (A * B) (T) = B(T) * A(T). Cublas matrice B(T) and A(T)
+* happen to be C/C++ matrice B and A (still because of the implicit transpose)!
+* We don't need extra transpose code, we only need alter the input order!
+*
+* CUBLAS provides high-performance matrix multiplication.
+* See also:
+* V. Volkov and J. Demmel, "Benchmarking GPUs to tune dense linear algebra,"
+* in Proc. 2008 ACM/IEEE Conf. on Supercomputing (SC '08),
+* Piscataway, NJ: IEEE Press, 2008, pp. Art. 31:1-11.
+*/
+
+#include <cublas_v2.h>
+#include "../../common.hpp"
+
+
+// Optional Command-line multiplier for matrix sizes
+typedef struct _matrixSize {
+	unsigned int uiWA, uiHA, uiWB, uiHB, uiWC, uiHC;
+} sMatrixSize;
+
+////////////////////////////////////////////////////////////////////////////////
+//! Compute reference data set matrix multiply on CPU
+//! C = A * B
+//! @param C          reference data, computed but preallocated
+//! @param A          matrix A as provided to device
+//! @param B          matrix B as provided to device
+//! @param hA         height of matrix A
+//! @param wB         width of matrix B
+////////////////////////////////////////////////////////////////////////////////
+void matrixMulCPU(float *C, const float *A, const float *B, unsigned int hA,
+				  unsigned int wA, unsigned int wB)
+{
+	for (unsigned int i = 0; i < hA; ++i)
+		for (unsigned int j = 0; j < wB; ++j) {
+			double sum = 0;
+
+			for (unsigned int k = 0; k < wA; ++k) {
+				double a = A[i * wA + k];
+				double b = B[k * wB + j];
+				sum += a * b;
+			}
+
+			C[i * wB + j] = (float) sum;
+		}
+}
+
+inline bool compare_l2_norm(
+	cuda::span<float const> reference,
+	cuda::span<const float> data,
+	float const epsilon)
+{
+	if (reference.size() != data.size()) {
+		std::cerr << "Sizes of two spans to be compared - differ.";
+		exit(EXIT_FAILURE);
+	}
+	assert_(epsilon >= 0);
+
+	float error = 0;
+	float ref = 0;
+
+	for (unsigned int i = 0; i < data.size(); ++i) {
+		float diff = reference[i] - data[i];
+		error += diff * diff;
+		ref += reference[i] * reference[i];
+	}
+
+	float normRef = ::sqrtf(ref);
+
+	if (fabs(ref) < 1e-7) {
+		std::cerr << "ERROR, reference l2-norm is 0\n";
+		exit(EXIT_FAILURE);
+	}
+
+	float normError = ::sqrtf(error);
+	error = normError / normRef;
+	bool result = error < epsilon;
+	if (not result) {
+		std::cerr << "ERROR, L2-norm error " << error << " is greater than epsilon " << epsilon << "\n";
+	}
+	return result;
+}
+
+sMatrixSize initialize_matrix_dimensions()
+{
+	auto matrix_size_multiplier{5};
+	sMatrixSize matrix_dims;
+	int block_size{32};
+
+	matrix_dims.uiWA = 3 * block_size * matrix_size_multiplier;
+	matrix_dims.uiHA = 4 * block_size * matrix_size_multiplier;
+
+	matrix_dims.uiWB = 2 * block_size * matrix_size_multiplier;
+	matrix_dims.uiHB = 3 * block_size * matrix_size_multiplier;
+
+	matrix_dims.uiWC = 2 * block_size * matrix_size_multiplier;
+	matrix_dims.uiHC = 4 * block_size * matrix_size_multiplier;
+
+	std::cout
+		<< "MatrixA(" << matrix_dims.uiHA << ',' << matrix_dims.uiWA << "), "
+		<< "MatrixB(" << matrix_dims.uiHB << ',' << matrix_dims.uiWB << "), "
+		<< "MatrixC(" << matrix_dims.uiHC << ',' << matrix_dims.uiWC << ")\n";
+
+	if (matrix_dims.uiWA != matrix_dims.uiHB ||
+		matrix_dims.uiHA != matrix_dims.uiHC ||
+		matrix_dims.uiWB != matrix_dims.uiWC) {
+		printf("ERROR: Matrix sizes do not match!\n");
+		exit(EXIT_FAILURE);
+	}
+	return matrix_dims;
+}
+
+void multiply_and_time_with_cublas(
+	cuda::device_t device,
+	cuda::span<float> d_A,
+	cuda::span<float> d_B,
+	cuda::span<float> d_C,
+	cuda::span<float> h_CUBLAS,
+	sMatrixSize matrix_dims,
+	int num_iterations)
+{
+	std::cout << "Computing result using CUBLAS... ";
+
+	const float alpha = 1.0f;
+	const float beta = 0.0f;
+	cublasHandle_t handle;
+
+	cublasCreate(&handle);
+
+	// Perform warmup operation with cublas
+	cublasSgemm(
+		handle, CUBLAS_OP_N, CUBLAS_OP_N,
+		matrix_dims.uiWB, matrix_dims.uiHA, matrix_dims.uiWA, // m, n, k
+		&alpha, d_B.data(),
+		matrix_dims.uiWB, // lda
+		d_A.data(),
+		matrix_dims.uiWA, // ldb
+		&beta,
+		d_C.data(),
+		matrix_dims.uiWB // ldc
+	);
+
+	// Allocate CUDA events that we'll use for timing
+
+	// Record the start event
+	auto stream = device.default_stream();
+	auto start = stream.enqueue.event();
+
+	for (int iteration_index = 0; iteration_index < num_iterations; iteration_index++) {
+		// note cublas is column primary!
+		// need to transpose the order
+		cublasSgemm(
+			handle, CUBLAS_OP_N, CUBLAS_OP_N, matrix_dims.uiWB, matrix_dims.uiHA,
+			matrix_dims.uiWA, &alpha, d_B.data(), matrix_dims.uiWB, d_A.data(),
+			matrix_dims.uiWA, &beta, d_C.data(), matrix_dims.uiWB);
+	}
+	auto end = stream.enqueue.event();
+
+	std::cout << "done.\n";
+
+	// Wait for the stop event to complete
+	end.synchronize();
+
+	auto total = cuda::event::time_elapsed_between(start, end);
+
+	// Compute and print the performance
+	auto msec_per_iteration = total.count() / num_iterations;
+	double ops_per_multiplication = 2.0 * (double) matrix_dims.uiHC *
+									(double) matrix_dims.uiWC *
+									(double) matrix_dims.uiHB;
+	double giga_ops_per_second =
+		(ops_per_multiplication * 1.0e-9f) / (msec_per_iteration / 1000.0f);
+	printf("Performance= %.2f GFlop/s, Time= %.3f msec, Size= %.0f Ops\n",
+		giga_ops_per_second, msec_per_iteration, ops_per_multiplication);
+
+	cuda::memory::copy(h_CUBLAS, d_C);
+
+	// Destroy the handle
+	cublasDestroy(handle);
+}
+
+////////////////////////////////////////////////////////////////////////////////
+//! Run a simple test matrix multiply using CUBLAS
+////////////////////////////////////////////////////////////////////////////////
+
+int main(int argc, char **argv)
+{
+	std::cout << "[Matrix Multiply CUBLAS] - Starting...\n";
+	auto device_id = choose_device(argc, argv);
+	auto device = cuda::device::get(device_id);
+
+	std::cout << "GPU Device " << device_id << ": \"" << device.name() << "\" "
+			  << "with compute capability " << device.compute_capability() << '\n';
+
+	auto matrix_dims = initialize_matrix_dimensions();
+	int num_iterations = 30;
+
+	auto size_A = matrix_dims.uiWA * matrix_dims.uiHA;
+	auto size_B = matrix_dims.uiWB * matrix_dims.uiHB;
+	auto size_C = matrix_dims.uiWC * matrix_dims.uiHC;
+
+	auto h_A = cuda::make_unique_span<float>(size_A);
+	auto h_B = cuda::make_unique_span<float>(size_B);
+	auto h_CUBLAS_result = cuda::make_unique_span<float>(size_C);
+
+	// set seed for rand()
+	srand(2006);
+
+	// initialize host memory
+	auto generator = []() { return rand() / (float) RAND_MAX; };
+	std::generate(h_A.begin(), h_A.end(), generator);
+	std::generate(h_B.begin(), h_B.end(), generator);
+
+	// allocate device memory
+	auto d_A = cuda::memory::make_unique_span<float>(device, size_A);
+	auto d_B = cuda::memory::make_unique_span<float>(device, size_B);
+	auto d_C = cuda::memory::make_unique_span<float>(device, size_C);
+
+	cuda::memory::copy(d_A, h_A);
+	cuda::memory::copy(d_B, h_B);
+
+	multiply_and_time_with_cublas(device, d_A, d_B, d_C, h_CUBLAS_result, matrix_dims, num_iterations);
+
+	// compute reference solution
+	std::cout << "Computing result using host CPU... ";
+	auto h_CPU_result = cuda::make_unique_span<float>(size_C);
+	matrixMulCPU(h_CPU_result.data(), h_A.data(), h_B.data(), matrix_dims.uiHA, matrix_dims.uiWA, matrix_dims.uiWB);
+	std::cout << "done.\n";
+
+	bool about_equal = compare_l2_norm(h_CPU_result, h_CUBLAS_result, 1.0e-6f);
+
+	std::cout << "CUBLAS Matrix Multiply is close enough to CPU results: " << (about_equal ? "Yes" : "No") << '\n';
+	std::cout << (about_equal ? "SUCCESS" : "FAILURE") << '\n';
+}