| 33 | { |
| 34 | #ifndef BARE_METAL |
| 35 | std::pair<unsigned, unsigned> split_2d(unsigned max_threads, std::size_t m, std::size_t n) |
| 36 | { |
| 37 | /* |
| 38 | * We want the same ratio of threads in M & N to the ratio of m and n problem size |
| 39 | * |
| 40 | * Therefore: mt/nt == m/n where mt*nt == max_threads |
| 41 | * |
| 42 | * max_threads/nt = mt & (max_threads/nt) * (m/n) = nt |
| 43 | * nt^2 = max_threads * (m/n) |
| 44 | * nt = sqrt( max_threads * (m/n) ) |
| 45 | */ |
| 46 | //ratio of m to n in problem dimensions |
| 47 | double ratio = m / static_cast<double>(n); |
| 48 | |
| 49 | // nt = sqrt(max_threads * (m / n) ) |
| 50 | const unsigned adjusted = std::round(std::sqrt(max_threads * ratio)); |
| 51 | |
| 52 | //find the nearest factor of max_threads |
| 53 | for (unsigned i = 0; i != adjusted; ++i) |
| 54 | { |
| 55 | //try down |
| 56 | const unsigned adj_down = adjusted - i; |
| 57 | if (max_threads % adj_down == 0) |
| 58 | { |
| 59 | return {adj_down, max_threads / adj_down}; |
| 60 | } |
| 61 | |
| 62 | //try up |
| 63 | const unsigned adj_up = adjusted + i; |
| 64 | if (max_threads % adj_up == 0) |
| 65 | { |
| 66 | return {adj_up, max_threads / adj_up}; |
| 67 | } |
| 68 | } |
| 69 | |
| 70 | //we didn't find anything so lets bail out with maxes biased to the largest dimension |
| 71 | if (m > n) |
| 72 | { |
| 73 | return {std::min<unsigned>(m, max_threads), 1}; |
| 74 | } |
| 75 | else |
| 76 | { |
| 77 | return {1, std::min<unsigned>(n, max_threads)}; |
| 78 | } |
| 79 | } |
| 80 | #endif /* #ifndef BARE_METAL */ |
| 81 | } // namespace scheduler_utils |
| 82 | } // namespace arm_compute |
no test coverage detected