146 lines
6.7 KiB
C++
146 lines
6.7 KiB
C++
// Copyright 2009-2020 Intel Corporation
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// SPDX-License-Identifier: Apache-2.0
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#pragma once
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#include "parallel_for.h"
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namespace embree
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{
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template<typename Index, typename Value, typename Func, typename Reduction>
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__forceinline Value sequential_reduce( const Index first, const Index last, const Value& identity, const Func& func, const Reduction& reduction )
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{
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return func(range<Index>(first,last));
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}
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template<typename Index, typename Value, typename Func, typename Reduction>
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__forceinline Value sequential_reduce( const Index first, const Index last, const Index minStepSize, const Value& identity, const Func& func, const Reduction& reduction )
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{
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return func(range<Index>(first,last));
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}
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template<typename Index, typename Value, typename Func, typename Reduction>
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__noinline Value parallel_reduce_internal( Index taskCount, const Index first, const Index last, const Index minStepSize, const Value& identity, const Func& func, const Reduction& reduction )
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{
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const Index maxTasks = 512;
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const Index threadCount = (Index) TaskScheduler::threadCount();
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taskCount = min(taskCount,threadCount,maxTasks);
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/* parallel invokation of all tasks */
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dynamic_large_stack_array(Value,values,taskCount,8192); // consumes at most 8192 bytes on the stack
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parallel_for(taskCount, [&](const Index taskIndex) {
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const Index k0 = first+(taskIndex+0)*(last-first)/taskCount;
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const Index k1 = first+(taskIndex+1)*(last-first)/taskCount;
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values[taskIndex] = func(range<Index>(k0,k1));
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});
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/* perform reduction over all tasks */
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Value v = identity;
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for (Index i=0; i<taskCount; i++) v = reduction(v,values[i]);
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return v;
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}
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template<typename Index, typename Value, typename Func, typename Reduction>
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__forceinline Value parallel_reduce( const Index first, const Index last, const Index minStepSize, const Value& identity, const Func& func, const Reduction& reduction )
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{
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#if defined(TASKING_INTERNAL)
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/* fast path for small number of iterations */
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Index taskCount = (last-first+minStepSize-1)/minStepSize;
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if (likely(taskCount == 1)) {
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return func(range<Index>(first,last));
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}
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return parallel_reduce_internal(taskCount,first,last,minStepSize,identity,func,reduction);
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#elif defined(TASKING_TBB)
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#if TBB_INTERFACE_VERSION >= 12002
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tbb::task_group_context context;
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const Value v = tbb::parallel_reduce(tbb::blocked_range<Index>(first,last,minStepSize),identity,
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[&](const tbb::blocked_range<Index>& r, const Value& start) { return reduction(start,func(range<Index>(r.begin(),r.end()))); },
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reduction,context);
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if (context.is_group_execution_cancelled())
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throw std::runtime_error("task cancelled");
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return v;
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#else
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const Value v = tbb::parallel_reduce(tbb::blocked_range<Index>(first,last,minStepSize),identity,
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[&](const tbb::blocked_range<Index>& r, const Value& start) { return reduction(start,func(range<Index>(r.begin(),r.end()))); },
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reduction);
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if (tbb::task::self().is_cancelled())
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throw std::runtime_error("task cancelled");
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return v;
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#endif
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#else // TASKING_PPL
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struct AlignedValue
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{
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char storage[__alignof(Value)+sizeof(Value)];
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static uintptr_t alignUp(uintptr_t p, size_t a) { return p + (~(p - 1) % a); };
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Value* getValuePtr() { return reinterpret_cast<Value*>(alignUp(uintptr_t(storage), __alignof(Value))); }
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const Value* getValuePtr() const { return reinterpret_cast<Value*>(alignUp(uintptr_t(storage), __alignof(Value))); }
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AlignedValue(const Value& v) { new(getValuePtr()) Value(v); }
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AlignedValue(const AlignedValue& v) { new(getValuePtr()) Value(*v.getValuePtr()); }
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AlignedValue(const AlignedValue&& v) { new(getValuePtr()) Value(*v.getValuePtr()); };
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AlignedValue& operator = (const AlignedValue& v) { *getValuePtr() = *v.getValuePtr(); return *this; };
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AlignedValue& operator = (const AlignedValue&& v) { *getValuePtr() = *v.getValuePtr(); return *this; };
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operator Value() const { return *getValuePtr(); }
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};
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struct Iterator_Index
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{
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Index v;
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typedef std::forward_iterator_tag iterator_category;
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typedef AlignedValue value_type;
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typedef Index difference_type;
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typedef Index distance_type;
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typedef AlignedValue* pointer;
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typedef AlignedValue& reference;
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__forceinline Iterator_Index() {}
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__forceinline Iterator_Index(Index v) : v(v) {}
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__forceinline bool operator== (Iterator_Index other) { return v == other.v; }
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__forceinline bool operator!= (Iterator_Index other) { return v != other.v; }
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__forceinline Iterator_Index operator++() { return Iterator_Index(++v); }
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__forceinline Iterator_Index operator++(int) { return Iterator_Index(v++); }
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};
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auto range_reduction = [&](Iterator_Index begin, Iterator_Index end, const AlignedValue& start) {
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assert(begin.v < end.v);
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return reduction(start, func(range<Index>(begin.v, end.v)));
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};
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const Value v = concurrency::parallel_reduce(Iterator_Index(first), Iterator_Index(last), AlignedValue(identity), range_reduction, reduction);
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return v;
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#endif
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}
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template<typename Index, typename Value, typename Func, typename Reduction>
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__forceinline Value parallel_reduce( const Index first, const Index last, const Index minStepSize, const Index parallel_threshold, const Value& identity, const Func& func, const Reduction& reduction )
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{
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if (likely(last-first < parallel_threshold)) {
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return func(range<Index>(first,last));
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} else {
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return parallel_reduce(first,last,minStepSize,identity,func,reduction);
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}
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}
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template<typename Index, typename Value, typename Func, typename Reduction>
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__forceinline Value parallel_reduce( const range<Index> range, const Index minStepSize, const Index parallel_threshold, const Value& identity, const Func& func, const Reduction& reduction )
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{
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return parallel_reduce(range.begin(),range.end(),minStepSize,parallel_threshold,identity,func,reduction);
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}
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template<typename Index, typename Value, typename Func, typename Reduction>
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__forceinline Value parallel_reduce( const Index first, const Index last, const Value& identity, const Func& func, const Reduction& reduction )
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{
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auto funcr = [&] ( const range<Index> r ) {
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Value v = identity;
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for (Index i=r.begin(); i<r.end(); i++)
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v = reduction(v,func(i));
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return v;
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};
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return parallel_reduce(first,last,Index(1),identity,funcr,reduction);
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}
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template<typename Index, typename Value, typename Func, typename Reduction>
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__forceinline Value parallel_reduce( const range<Index> range, const Value& identity, const Func& func, const Reduction& reduction )
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{
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return parallel_reduce(range.begin(),range.end(),Index(1),identity,func,reduction);
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}
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}
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