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Diffstat (limited to 'src/core/NEON/kernels/arm_gemm/barrier.hpp')
-rw-r--r-- | src/core/NEON/kernels/arm_gemm/barrier.hpp | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/src/core/NEON/kernels/arm_gemm/barrier.hpp b/src/core/NEON/kernels/arm_gemm/barrier.hpp new file mode 100644 index 0000000000..cfd1079f74 --- /dev/null +++ b/src/core/NEON/kernels/arm_gemm/barrier.hpp @@ -0,0 +1,83 @@ +/* + * Copyright (c) 2019 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. + */ +#pragma once + +#ifndef NO_MULTI_THREADING + +#include <atomic> + +namespace arm_gemm { + +class barrier { +private: + unsigned int m_threads; + + std::atomic<unsigned int> m_waiters; + std::atomic<unsigned int> m_leavers; + +public: + barrier(unsigned int threads) : m_threads(threads), m_waiters(0), m_leavers(0) { } + + /* This isn't safe if any thread is waiting... */ + void set_nthreads(unsigned int nthreads) { + m_threads = nthreads; + } + + void arrive_and_wait() { + m_waiters++; + + while (m_waiters != m_threads) { + ; /* spin */ + } + + unsigned int v = m_leavers.fetch_add(1); + + if (v == (m_threads - 1)) { + m_waiters -= m_threads; + m_leavers = 0; + } else { + while (m_leavers > 0) { + ; /* spin */ + } + } + } +}; + +} // namespace arm_gemm + +#else + +namespace arm_gemm { + +class barrier { +public: + barrier(unsigned int) { } + + void arrive_and_wait() { } + void set_nthreads(unsigned int ) { } +}; + +} // namespace arm_gemm + +#endif |