74 lines
2.2 KiB
Text
74 lines
2.2 KiB
Text
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#include "kernel_config.cuh"
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#include <algorithm>
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#include <cstdio>
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size_t KernelConfig::total_threads() const {
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return (size_t)blocks.x * blocks.y * blocks.z * threads.x * threads.y *
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threads.z;
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}
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void KernelConfig::print() const {
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printf("Grid: (%u, %u, %u), Block: (%u, %u, %u), Total threads: %zu\n",
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blocks.x, blocks.y, blocks.z, threads.x, threads.y, threads.z,
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total_threads());
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}
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KernelConfig get_launch_config(size_t n_elements, int threads_per_block,
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int max_blocks_per_dim) {
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// Ensure threads_per_block is valid
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threads_per_block = std::min(threads_per_block, 1024);
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threads_per_block = std::max(threads_per_block, 32);
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// Calculate total blocks needed
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size_t total_blocks =
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(n_elements + threads_per_block - 1) / threads_per_block;
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dim3 threads(threads_per_block);
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dim3 blocks;
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if (total_blocks <= max_blocks_per_dim) {
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// Simple 1D grid
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blocks = dim3(total_blocks);
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} else {
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// Use 2D grid
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blocks.x = max_blocks_per_dim;
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blocks.y = (total_blocks + max_blocks_per_dim - 1) / max_blocks_per_dim;
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// If still too big, use 3D grid
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if (blocks.y > max_blocks_per_dim) {
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blocks.y = max_blocks_per_dim;
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blocks.z =
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(total_blocks + (size_t)max_blocks_per_dim * max_blocks_per_dim - 1) /
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((size_t)max_blocks_per_dim * max_blocks_per_dim);
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}
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}
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return KernelConfig(blocks, threads);
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}
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int get_optimal_block_size(int device_id) {
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cudaDeviceProp prop;
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cudaGetDeviceProperties(&prop, device_id);
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// Use a fraction of max threads per block for better occupancy
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// Typically 256 or 512 work well for most kernels
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if (prop.maxThreadsPerBlock >= 1024) {
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return 256; // Good balance of occupancy and register usage
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} else if (prop.maxThreadsPerBlock >= 512) {
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return 256;
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} else {
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return prop.maxThreadsPerBlock / 2;
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}
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}
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KernelConfig get_launch_config_advanced(size_t n_elements, int device_id) {
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cudaDeviceProp prop;
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cudaGetDeviceProperties(&prop, device_id);
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int threads_per_block = get_optimal_block_size(device_id);
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int max_blocks_per_dim = prop.maxGridSize[0];
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return get_launch_config(n_elements, threads_per_block, max_blocks_per_dim);
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}
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