| /* |
| * Copyright (c) 2020 Arm Limited. |
| * |
| * SPDX-License-Identifier: MIT |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to |
| * deal in the Software without restriction, including without limitation the |
| * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or |
| * sell copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in all |
| * copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| * SOFTWARE. |
| */ |
| #include "src/runtime/SchedulerUtils.h" |
| |
| #include "arm_compute/core/Error.h" |
| |
| #include <cmath> |
| |
| namespace arm_compute |
| { |
| namespace scheduler_utils |
| { |
| #ifndef BARE_METAL |
| std::pair<unsigned, unsigned> split_2d(unsigned max_threads, std::size_t m, std::size_t n) |
| { |
| /* |
| * We want the same ratio of threads in M & N to the ratio of m and n problem size |
| * |
| * Therefore: mt/nt == m/n where mt*nt == max_threads |
| * |
| * max_threads/nt = mt & (max_threads/nt) * (m/n) = nt |
| * nt^2 = max_threads * (m/n) |
| * nt = sqrt( max_threads * (m/n) ) |
| */ |
| //ratio of m to n in problem dimensions |
| double ratio = m / static_cast<double>(n); |
| |
| // nt = sqrt(max_threads * (m / n) ) |
| const unsigned adjusted = std::round( |
| std::sqrt(max_threads * ratio)); |
| |
| //find the nearest factor of max_threads |
| for(unsigned i = 0; i != adjusted; ++i) |
| { |
| //try down |
| const unsigned adj_down = adjusted - i; |
| if(max_threads % adj_down == 0) |
| { |
| return { adj_down, max_threads / adj_down }; |
| } |
| |
| //try up |
| const unsigned adj_up = adjusted + i; |
| if(max_threads % adj_up == 0) |
| { |
| return { adj_up, max_threads / adj_up }; |
| } |
| } |
| |
| //we didn't find anything so lets bail out with maxes biased to the largest dimension |
| if(m > n) |
| { |
| return { std::min<unsigned>(m, max_threads), 1 }; |
| } |
| else |
| { |
| return { 1, std::min<unsigned>(n, max_threads) }; |
| } |
| } |
| #endif /* #ifndef BARE_METAL */ |
| } // namespace scheduler_utils |
| } // namespace arm_compute |