HIP (Heterogeneous-Compute Interface for Portability) is an open-source C++ runtime API and kernel language that allows developers to create portable applications for AMD and NVIDIA GPUs. It provides a way to write code that can run on both AMD ROCm and NVIDIA CUDA platforms, enabling easier migration between GPU architectures.

Pros

• Portability between AMD and NVIDIA GPUs
• Simplified code migration from CUDA to HIP
• Open-source and actively maintained by AMD
• Supports a wide range of GPU computing applications

Cons

• Performance may not always match native CUDA or ROCm implementations
• Limited support for some advanced CUDA features
• Learning curve for developers familiar with only one platform
• Ecosystem and community support still growing compared to CUDA

Code Examples

1. Vector Addition:

__global__ void vectorAdd(float* a, float* b, float* c, int n) {
    int i = blockDim.x * blockIdx.x + threadIdx.x;
    if (i < n) {
        c[i] = a[i] + b[i];
    }
}

// Host code
hipLaunchKernelGGL(vectorAdd, dim3(gridSize), dim3(blockSize), 0, 0, d_a, d_b, d_c, n);

2. Matrix Multiplication:

__global__ void matrixMul(float* A, float* B, float* C, int width) {
    int row = blockIdx.y * blockDim.y + threadIdx.y;
    int col = blockIdx.x * blockDim.x + threadIdx.x;
    float sum = 0.0f;
    for (int i = 0; i < width; ++i) {
        sum += A[row * width + i] * B[i * width + col];
    }
    C[row * width + col] = sum;
}

// Host code
hipLaunchKernelGGL(matrixMul, dim3(gridSize), dim3(blockSize), 0, 0, d_A, d_B, d_C, width);

3. Device Memory Allocation and Copy:

float* h_data = new float[size];
float* d_data;
hipMalloc(&d_data, size * sizeof(float));
hipMemcpy(d_data, h_data, size * sizeof(float), hipMemcpyHostToDevice);

// After computation
hipMemcpy(h_data, d_data, size * sizeof(float), hipMemcpyDeviceToHost);
hipFree(d_data);
delete[] h_data;

Getting Started

1. Install ROCm (for AMD GPUs) or CUDA (for NVIDIA GPUs)
2. Clone the HIP repository:

   git clone https://github.com/ROCm-Developer-Tools/HIP.git
   

3. Build and install HIP:

   cd HIP
   mkdir build && cd build
   cmake ..
   make -j$(nproc)
   sudo make install
   

4. Set up environment variables:

   export HIP_PLATFORM=hcc  # For AMD GPUs
   export HIP_PLATFORM=nvcc # For NVIDIA GPUs
   

5. Compile your HIP program:

   hipcc your_program.cpp -o your_program