forked from OSchip/llvm-project
89 lines
3.2 KiB
C++
89 lines
3.2 KiB
C++
//===------- state-queuei.h - OpenMP GPU State Queue ------------- CUDA -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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//
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// This file contains the implementation of a queue to hand out OpenMP state
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// objects to teams of one or more kernels.
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//
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// Reference:
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// Thomas R.W. Scogland and Wu-chun Feng. 2015.
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// Design and Evaluation of Scalable Concurrent Queues for Many-Core
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// Architectures. International Conference on Performance Engineering.
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//
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//===----------------------------------------------------------------------===//
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#include "state-queue.h"
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template <typename ElementType, uint32_t SIZE>
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INLINE uint32_t omptarget_nvptx_Queue<ElementType, SIZE>::ENQUEUE_TICKET() {
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return __kmpc_atomic_add((unsigned int *)&tail, 1u);
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}
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template <typename ElementType, uint32_t SIZE>
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INLINE uint32_t omptarget_nvptx_Queue<ElementType, SIZE>::DEQUEUE_TICKET() {
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return __kmpc_atomic_add((unsigned int *)&head, 1u);
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}
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template <typename ElementType, uint32_t SIZE>
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INLINE uint32_t omptarget_nvptx_Queue<ElementType, SIZE>::ID(uint32_t ticket) {
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return (ticket / SIZE) * 2;
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}
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template <typename ElementType, uint32_t SIZE>
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INLINE bool omptarget_nvptx_Queue<ElementType, SIZE>::IsServing(uint32_t slot,
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uint32_t id) {
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return __kmpc_atomic_add((unsigned int *)&ids[slot], 0u) == id;
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}
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template <typename ElementType, uint32_t SIZE>
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INLINE void
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omptarget_nvptx_Queue<ElementType, SIZE>::PushElement(uint32_t slot,
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ElementType *element) {
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__kmpc_atomic_exchange((unsigned long long *)&elementQueue[slot],
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(unsigned long long)element);
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}
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template <typename ElementType, uint32_t SIZE>
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INLINE ElementType *
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omptarget_nvptx_Queue<ElementType, SIZE>::PopElement(uint32_t slot) {
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return (ElementType *)__kmpc_atomic_add(
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(unsigned long long *)&elementQueue[slot], (unsigned long long)0);
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}
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template <typename ElementType, uint32_t SIZE>
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INLINE void omptarget_nvptx_Queue<ElementType, SIZE>::DoneServing(uint32_t slot,
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uint32_t id) {
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__kmpc_atomic_exchange((unsigned int *)&ids[slot], (id + 1) % MAX_ID);
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}
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template <typename ElementType, uint32_t SIZE>
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INLINE void
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omptarget_nvptx_Queue<ElementType, SIZE>::Enqueue(ElementType *element) {
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uint32_t ticket = ENQUEUE_TICKET();
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uint32_t slot = ticket % SIZE;
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uint32_t id = ID(ticket) + 1;
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while (!IsServing(slot, id))
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;
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PushElement(slot, element);
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DoneServing(slot, id);
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}
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template <typename ElementType, uint32_t SIZE>
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INLINE ElementType *omptarget_nvptx_Queue<ElementType, SIZE>::Dequeue() {
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uint32_t ticket = DEQUEUE_TICKET();
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uint32_t slot = ticket % SIZE;
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uint32_t id = ID(ticket);
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while (!IsServing(slot, id))
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;
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ElementType *element = PopElement(slot);
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// This is to populate the queue because of the lack of GPU constructors.
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if (element == 0)
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element = &elements[slot];
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DoneServing(slot, id);
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return element;
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}
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