Revision control
++ // Copyright 2009-2021 Intel Corporation
++ // SPDX-License-Identifier: Apache-2.0
++
++ #pragma once
++
++ #include "intrinsics.h"
++ #include "sysinfo.h"
++ #include "atomic.h"
++
++ namespace embree
++ {
++ /*! system barrier using operating system */
++ class BarrierSys
++ {
++ public:
++
++ /*! construction / destruction */
++ BarrierSys (size_t N = 0);
++ ~BarrierSys ();
++
++ private:
++ /*! class in non-copyable */
++ BarrierSys (const BarrierSys& other) DELETED; // do not implement
++ BarrierSys& operator= (const BarrierSys& other) DELETED; // do not implement
++
++ public:
++ /*! intializes the barrier with some number of threads */
++ void init(size_t count);
++
++ /*! lets calling thread wait in barrier */
++ void wait();
++
++ private:
++ void* opaque;
++ };
++
++ /*! fast active barrier using atomitc counter */
++ struct BarrierActive
++ {
++ public:
++ BarrierActive ()
++ : cntr(0) {}
++
++ void reset() {
++ cntr.store(0);
++ }
++
++ void wait (size_t numThreads)
++ {
++ cntr++;
++ while (cntr.load() != numThreads)
++ pause_cpu();
++ }
++
++ private:
++ std::atomic<size_t> cntr;
++ };
++
++ /*! fast active barrier that does not require initialization to some number of threads */
++ struct BarrierActiveAutoReset
++ {
++ public:
++ BarrierActiveAutoReset ()
++ : cntr0(0), cntr1(0) {}
++
++ void wait (size_t threadCount)
++ {
++ cntr0.fetch_add(1);
++ while (cntr0 != threadCount) pause_cpu();
++ cntr1.fetch_add(1);
++ while (cntr1 != threadCount) pause_cpu();
++ cntr0.fetch_add(-1);
++ while (cntr0 != 0) pause_cpu();
++ cntr1.fetch_add(-1);
++ while (cntr1 != 0) pause_cpu();
++ }
++
++ private:
++ std::atomic<size_t> cntr0;
++ std::atomic<size_t> cntr1;
++ };
++
++ class LinearBarrierActive
++ {
++ public:
++
++ /*! construction and destruction */
++ LinearBarrierActive (size_t threadCount = 0);
++ ~LinearBarrierActive();
++
++ private:
++ /*! class in non-copyable */
++ LinearBarrierActive (const LinearBarrierActive& other) DELETED; // do not implement
++ LinearBarrierActive& operator= (const LinearBarrierActive& other) DELETED; // do not implement
++
++ public:
++ /*! intializes the barrier with some number of threads */
++ void init(size_t threadCount);
++
++ /*! thread with threadIndex waits in the barrier */
++ void wait (const size_t threadIndex);
++
++ private:
++ volatile unsigned char* count0;
++ volatile unsigned char* count1;
++ volatile unsigned int mode;
++ volatile unsigned int flag0;
++ volatile unsigned int flag1;
++ volatile size_t threadCount;
++ };
++ }
++