tbb/parallel_for.h

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/*
    Copyright (c) 2005-2020 Intel Corporation

    Licensed under the Apache License, Version 2.0 (the "License");
    you may not use this file except in compliance with the License.
    You may obtain a copy of the License at

        http://www.apache.org/licenses/LICENSE-2.0

    Unless required by applicable law or agreed to in writing, software
    distributed under the License is distributed on an "AS IS" BASIS,
    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    See the License for the specific language governing permissions and
    limitations under the License.
*/

#ifndef __TBB_parallel_for_H
#define __TBB_parallel_for_H

#define __TBB_parallel_for_H_include_area
#include "internal/_warning_suppress_enable_notice.h"

#include <new>
#include "task.h"
#include "partitioner.h"
#include "blocked_range.h"
#include "tbb_exception.h"
#include "internal/_tbb_trace_impl.h"

namespace tbb {

namespace interface9 {
namespace internal {

    void* allocate_sibling(task* start_for_task, size_t bytes);


    template<typename Range, typename Body, typename Partitioner>
    class start_for: public task {
        Range my_range;
        const Body my_body;
        typename Partitioner::task_partition_type my_partition;
        task* execute() __TBB_override;

        void note_affinity( affinity_id id ) __TBB_override {
            my_partition.note_affinity( id );
        }

    public:
        start_for( const Range& range, const Body& body, Partitioner& partitioner ) :
            my_range(range),
            my_body(body),
            my_partition(partitioner)
        {
            tbb::internal::fgt_algorithm(tbb::internal::PARALLEL_FOR_TASK, this, NULL);
        }

        start_for( start_for& parent_, typename Partitioner::split_type& split_obj) :
            my_range(parent_.my_range, split_obj),
            my_body(parent_.my_body),
            my_partition(parent_.my_partition, split_obj)
        {
            my_partition.set_affinity(*this);
            tbb::internal::fgt_algorithm(tbb::internal::PARALLEL_FOR_TASK, this, (void *)&parent_);
        }

        start_for( start_for& parent_, const Range& r, depth_t d ) :
            my_range(r),
            my_body(parent_.my_body),
            my_partition(parent_.my_partition, split())
        {
            my_partition.set_affinity(*this);
            my_partition.align_depth( d );
            tbb::internal::fgt_algorithm(tbb::internal::PARALLEL_FOR_TASK, this, (void *)&parent_);
        }
        static void run(  const Range& range, const Body& body, Partitioner& partitioner ) {
            if( !range.empty() ) {
#if !__TBB_TASK_GROUP_CONTEXT || TBB_JOIN_OUTER_TASK_GROUP
                start_for& a = *new(task::allocate_root()) start_for(range,body,partitioner);
#else
                // Bound context prevents exceptions from body to affect nesting or sibling algorithms,
                // and allows users to handle exceptions safely by wrapping parallel_for in the try-block.
                task_group_context context(PARALLEL_FOR);
                start_for& a = *new(task::allocate_root(context)) start_for(range,body,partitioner);
#endif /* __TBB_TASK_GROUP_CONTEXT && !TBB_JOIN_OUTER_TASK_GROUP */
                // REGION BEGIN
                fgt_begin_algorithm( tbb::internal::PARALLEL_FOR_TASK, (void*)&context );
                task::spawn_root_and_wait(a);
                fgt_end_algorithm( (void*)&context );
                // REGION END
            }
        }
#if __TBB_TASK_GROUP_CONTEXT
        static void run(  const Range& range, const Body& body, Partitioner& partitioner, task_group_context& context ) {
            if( !range.empty() ) {
                start_for& a = *new(task::allocate_root(context)) start_for(range,body,partitioner);
                // REGION BEGIN
                fgt_begin_algorithm( tbb::internal::PARALLEL_FOR_TASK, (void*)&context );
                task::spawn_root_and_wait(a);
                fgt_end_algorithm( (void*)&context );
                // END REGION
            }
        }
#endif /* __TBB_TASK_GROUP_CONTEXT */
        void run_body( Range &r ) {
            fgt_alg_begin_body( tbb::internal::PARALLEL_FOR_TASK, (void *)const_cast<Body*>(&(this->my_body)), (void*)this );
            my_body( r );
            fgt_alg_end_body( (void *)const_cast<Body*>(&(this->my_body)) );
        }

        void offer_work(typename Partitioner::split_type& split_obj) {
            spawn( *new( allocate_sibling(static_cast<task*>(this), sizeof(start_for)) ) start_for(*this, split_obj) );
        }
        void offer_work(const Range& r, depth_t d = 0) {
            spawn( *new( allocate_sibling(static_cast<task*>(this), sizeof(start_for)) ) start_for(*this, r, d) );
        }
    };

    // TODO: 'inline' here is to avoid multiple definition error but for sake of code size this should not be inlined
    inline void* allocate_sibling(task* start_for_task, size_t bytes) {
        task* parent_ptr = new( start_for_task->allocate_continuation() ) flag_task();
        start_for_task->set_parent(parent_ptr);
        parent_ptr->set_ref_count(2);
        return &parent_ptr->allocate_child().allocate(bytes);
    }

    template<typename Range, typename Body, typename Partitioner>
    task* start_for<Range,Body,Partitioner>::execute() {
        my_partition.check_being_stolen( *this );
        my_partition.execute(*this, my_range);
        return NULL;
    }
} // namespace internal
} // namespace interfaceX

namespace internal {
    using interface9::internal::start_for;

    template<typename Function, typename Index>
    class parallel_for_body : internal::no_assign {
        const Function &my_func;
        const Index my_begin;
        const Index my_step;
    public:
        parallel_for_body( const Function& _func, Index& _begin, Index& _step )
            : my_func(_func), my_begin(_begin), my_step(_step) {}

        void operator()( const tbb::blocked_range<Index>& r ) const {
            // A set of local variables to help the compiler with vectorization of the following loop.
            Index b = r.begin();
            Index e = r.end();
            Index ms = my_step;
            Index k = my_begin + b*ms;

#if __INTEL_COMPILER
#pragma ivdep
#if __TBB_ASSERT_ON_VECTORIZATION_FAILURE
#pragma vector always assert
#endif
#endif
            for ( Index i = b; i < e; ++i, k += ms ) {
                my_func( k );
            }
        }
    };
} // namespace internal

// Requirements on Range concept are documented in blocked_range.h



template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body ) {
    internal::start_for<Range,Body,const __TBB_DEFAULT_PARTITIONER>::run(range,body,__TBB_DEFAULT_PARTITIONER());
}


template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, const simple_partitioner& partitioner ) {
    internal::start_for<Range,Body,const simple_partitioner>::run(range,body,partitioner);
}


template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, const auto_partitioner& partitioner ) {
    internal::start_for<Range,Body,const auto_partitioner>::run(range,body,partitioner);
}


template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, const static_partitioner& partitioner ) {
    internal::start_for<Range,Body,const static_partitioner>::run(range,body,partitioner);
}


template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, affinity_partitioner& partitioner ) {
    internal::start_for<Range,Body,affinity_partitioner>::run(range,body,partitioner);
}

#if __TBB_TASK_GROUP_CONTEXT

template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, task_group_context& context ) {
    internal::start_for<Range,Body,const __TBB_DEFAULT_PARTITIONER>::run(range, body, __TBB_DEFAULT_PARTITIONER(), context);
}


template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, const simple_partitioner& partitioner, task_group_context& context ) {
    internal::start_for<Range,Body,const simple_partitioner>::run(range, body, partitioner, context);
}


template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, const auto_partitioner& partitioner, task_group_context& context ) {
    internal::start_for<Range,Body,const auto_partitioner>::run(range, body, partitioner, context);
}


template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, const static_partitioner& partitioner, task_group_context& context ) {
    internal::start_for<Range,Body,const static_partitioner>::run(range, body, partitioner, context);
}


template<typename Range, typename Body>
void parallel_for( const Range& range, const Body& body, affinity_partitioner& partitioner, task_group_context& context ) {
    internal::start_for<Range,Body,affinity_partitioner>::run(range,body,partitioner, context);
}
#endif /* __TBB_TASK_GROUP_CONTEXT */


namespace strict_ppl {

template <typename Index, typename Function, typename Partitioner>
void parallel_for_impl(Index first, Index last, Index step, const Function& f, Partitioner& partitioner) {
    if (step <= 0 )
        internal::throw_exception(internal::eid_nonpositive_step); // throws std::invalid_argument
    else if (last > first) {
        // Above "else" avoids "potential divide by zero" warning on some platforms
        Index end = (last - first - Index(1)) / step + Index(1);
        tbb::blocked_range<Index> range(static_cast<Index>(0), end);
        internal::parallel_for_body<Function, Index> body(f, first, step);
        tbb::parallel_for(range, body, partitioner);
    }
}

template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f) {
    parallel_for_impl<Index,Function,const auto_partitioner>(first, last, step, f, auto_partitioner());
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, const simple_partitioner& partitioner) {
    parallel_for_impl<Index,Function,const simple_partitioner>(first, last, step, f, partitioner);
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, const auto_partitioner& partitioner) {
    parallel_for_impl<Index,Function,const auto_partitioner>(first, last, step, f, partitioner);
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, const static_partitioner& partitioner) {
    parallel_for_impl<Index,Function,const static_partitioner>(first, last, step, f, partitioner);
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, affinity_partitioner& partitioner) {
    parallel_for_impl(first, last, step, f, partitioner);
}

template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f) {
    parallel_for_impl<Index,Function,const auto_partitioner>(first, last, static_cast<Index>(1), f, auto_partitioner());
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f, const simple_partitioner& partitioner) {
    parallel_for_impl<Index,Function,const simple_partitioner>(first, last, static_cast<Index>(1), f, partitioner);
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f, const auto_partitioner& partitioner) {
    parallel_for_impl<Index,Function,const auto_partitioner>(first, last, static_cast<Index>(1), f, partitioner);
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f, const static_partitioner& partitioner) {
    parallel_for_impl<Index,Function,const static_partitioner>(first, last, static_cast<Index>(1), f, partitioner);
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f, affinity_partitioner& partitioner) {
    parallel_for_impl(first, last, static_cast<Index>(1), f, partitioner);
}

#if __TBB_TASK_GROUP_CONTEXT
template <typename Index, typename Function, typename Partitioner>
void parallel_for_impl(Index first, Index last, Index step, const Function& f, Partitioner& partitioner, tbb::task_group_context &context) {
    if (step <= 0 )
        internal::throw_exception(internal::eid_nonpositive_step); // throws std::invalid_argument
    else if (last > first) {
        // Above "else" avoids "potential divide by zero" warning on some platforms
        Index end = (last - first - Index(1)) / step + Index(1);
        tbb::blocked_range<Index> range(static_cast<Index>(0), end);
        internal::parallel_for_body<Function, Index> body(f, first, step);
        tbb::parallel_for(range, body, partitioner, context);
    }
}

template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, tbb::task_group_context &context) {
    parallel_for_impl<Index,Function,const auto_partitioner>(first, last, step, f, auto_partitioner(), context);
}
 template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, const simple_partitioner& partitioner, tbb::task_group_context &context) {
    parallel_for_impl<Index,Function,const simple_partitioner>(first, last, step, f, partitioner, context);
}
 template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, const auto_partitioner& partitioner, tbb::task_group_context &context) {
    parallel_for_impl<Index,Function,const auto_partitioner>(first, last, step, f, partitioner, context);
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, const static_partitioner& partitioner, tbb::task_group_context &context) {
    parallel_for_impl<Index,Function,const static_partitioner>(first, last, step, f, partitioner, context);
}
 template <typename Index, typename Function>
void parallel_for(Index first, Index last, Index step, const Function& f, affinity_partitioner& partitioner, tbb::task_group_context &context) {
    parallel_for_impl(first, last, step, f, partitioner, context);
}


template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f, tbb::task_group_context &context) {
    parallel_for_impl<Index,Function,const auto_partitioner>(first, last, static_cast<Index>(1), f, auto_partitioner(), context);
}
 template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f, const simple_partitioner& partitioner, tbb::task_group_context &context) {
    parallel_for_impl<Index,Function,const simple_partitioner>(first, last, static_cast<Index>(1), f, partitioner, context);
}
 template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f, const auto_partitioner& partitioner, tbb::task_group_context &context) {
    parallel_for_impl<Index,Function,const auto_partitioner>(first, last, static_cast<Index>(1), f, partitioner, context);
}
template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f, const static_partitioner& partitioner, tbb::task_group_context &context) {
    parallel_for_impl<Index,Function,const static_partitioner>(first, last, static_cast<Index>(1), f, partitioner, context);
}
 template <typename Index, typename Function>
void parallel_for(Index first, Index last, const Function& f, affinity_partitioner& partitioner, tbb::task_group_context &context) {
    parallel_for_impl(first, last, static_cast<Index>(1), f, partitioner, context);
}

#endif /* __TBB_TASK_GROUP_CONTEXT */


} // namespace strict_ppl

using strict_ppl::parallel_for;

} // namespace tbb

#if TBB_PREVIEW_SERIAL_SUBSET
#define __TBB_NORMAL_EXECUTION
#include "../serial/tbb/parallel_for.h"
#undef __TBB_NORMAL_EXECUTION
#endif

#include "internal/_warning_suppress_disable_notice.h"
#undef __TBB_parallel_for_H_include_area

#endif /* __TBB_parallel_for_H */