Andrew Kerr
96dab34ad9
CUTLASS 2.1 contributes: - BLAS-style host-side API added to CUTLASS Library - Planar Complex GEMM kernels targeting Volta and Turing Tensor Cores - Minor enhancements and bug fixes
107 lines
3.5 KiB
C++
107 lines
3.5 KiB
C++
/***************************************************************************************************
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* Copyright (c) 2017-2019, NVIDIA CORPORATION. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without modification, are permitted
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* provided that the following conditions are met:
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* * Redistributions of source code must retain the above copyright notice, this list of
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* conditions and the following disclaimer.
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* * Redistributions in binary form must reproduce the above copyright notice, this list of
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* conditions and the following disclaimer in the documentation and/or other materials
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* provided with the distribution.
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* * Neither the name of the NVIDIA CORPORATION nor the names of its contributors may be used
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* to endorse or promote products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL NVIDIA CORPORATION BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
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* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TOR (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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**************************************************************************************************/
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/*! \file
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\brief Implementation of a CTA-wide semaphore for inter-CTA synchronization.
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*/
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#pragma once
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#include "cutlass/cutlass.h"
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#include "cutlass/aligned_buffer.h"
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#include "cutlass/array.h"
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#include "cutlass/numeric_types.h"
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#include "cutlass/matrix_shape.h"
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#include "cutlass/gemm/gemm.h"
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/////////////////////////////////////////////////////////////////////////////////////////////////
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namespace cutlass {
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/////////////////////////////////////////////////////////////////////////////////////////////////
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/// CTA-wide semaphore for inter-CTA synchronization.
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class Semaphore {
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public:
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int *lock;
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bool wait_thread;
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int state;
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public:
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/// Implements a semaphore to wait for a flag to reach a given value
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CUTLASS_HOST_DEVICE
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Semaphore(int *lock_, int thread_id):
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lock(lock_),
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wait_thread(thread_id < 0 || thread_id == 0),
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state(-1) {
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}
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/// Permit fetching the synchronization mechanism early
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CUTLASS_DEVICE
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void fetch() {
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if (wait_thread) {
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asm volatile ("ld.global.cg.b32 %0, [%1];\n" : "=r"(state) : "l"(lock));
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}
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}
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/// Gets the internal state
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CUTLASS_DEVICE
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int get_state() const {
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return state;
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}
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/// Waits until the semaphore is equal to the given value
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CUTLASS_DEVICE
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void wait(int status = 0) {
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while( __syncthreads_and(state != status) ) {
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fetch();
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}
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__syncthreads();
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}
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/// Updates the lock with the given result
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CUTLASS_DEVICE
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void release(int status = 0) {
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__syncthreads();
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if (wait_thread) {
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asm volatile ("st.global.cg.b32 [%0], %1;\n" : : "l"(lock), "r"(status));
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}
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}
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};
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/////////////////////////////////////////////////////////////////////////////////////////////////
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} // namespace cutlass
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/////////////////////////////////////////////////////////////////////////////////////////////////
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