libcilkrts/runtime/reducer_impl.h

   1 /* reducer_impl.h                  -*-C++-*-
   2  *
   3  *************************************************************************
   4  *
   5  *  @copyright
   6  *  Copyright (C) 2009-2013, Intel Corporation
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  22  *      from this software without specific prior written permission.
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  24  *  @copyright
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  38
  39 /**
  40  * @file reducer_impl.h
  41  *
  42  * @brief Functions to implement reducers in the runtime.
  43  */
  44
  45 #ifndef INCLUDED_REDUCER_IMPL_DOT_H
  46 #define INCLUDED_REDUCER_IMPL_DOT_H
  47
  48 #include <cilk/common.h>
  49 #include <internal/abi.h>
  50 #include "rts-common.h"
  51
  52 __CILKRTS_BEGIN_EXTERN_C
  53
  54 /**
  55  * Construct an empty reducer map from the memory pool associated with the
  56  * given worker.  This reducer map must be destroyed before the worker's
  57  * associated global context is destroyed.
  58  *
  59  * @param w __cilkrts_worker the cilkred_map is being created for.
  60  *
  61  * @return Pointer to the initialized cilkred_map.
  62  */
  63 COMMON_SYSDEP
  64 cilkred_map *__cilkrts_make_reducer_map(__cilkrts_worker *w);
  65
  66 /**
  67  * Destroy a reducer map.  The map must have been allocated from the worker's
  68  * global context and should have been allocated from the same worker.
  69  *
  70  * @param w __cilkrts_worker the cilkred_map was created for.
  71  * @param h The cilkred_map to be deallocated.
  72  */
  73 COMMON_SYSDEP
  74 void __cilkrts_destroy_reducer_map(__cilkrts_worker *w,
  75                                    cilkred_map *h);
  76
  77 /**
  78  * Set the specified reducer map as the leftmost map if is_leftmost is true,
  79  * otherwise, set it to not be the leftmost map.
  80  *
  81  * @param h The cilkred_map to be modified.
  82  * @param is_leftmost true if the reducer map is leftmost.
  83  */
  84 COMMON_SYSDEP
  85 void __cilkrts_set_leftmost_reducer_map(cilkred_map *h,
  86                                         int is_leftmost);
  87
  88 /**
  89  * Merge reducer map RIGHT_MAP into LEFT_MAP and return the result of the
  90  * merge.  Both maps must be allocated from the global context associated
  91  * with the specified worker.  The returned reducer map must be destroyed
  92  * before the worker's associated global context is destroyed.
  93  *
  94  * If two cilkred_maps are specified, one will be destroyed and the other
  95  * one will be returned as the merged cilkred_map.
  96  *
  97  * When reducers can contain nested parallelism, execution can return
  98  * on a different worker than when it started (but still using the
  99  * same stack).
 100  *
 101  * Upon return, *w_ptr stores the pointer to the worker that execution
 102  * returns on.
 103  *
 104  * @param w_ptr      Pointer to the currently executing worker.
 105  * @param left_map   The left cilkred_map.
 106  * @param right_map  The right cilkred_map.
 107  *
 108  * @return pointer to merged cilkred_map.
 109  */
 110 extern
 111 cilkred_map *merge_reducer_maps(__cilkrts_worker **w_ptr,
 112                                 cilkred_map *left_map,
 113                                 cilkred_map *right_map);
 114
 115 /**
 116  * Similar to merge_reducer_maps(), except that after merging
 117  * RIGHT_MAP into LEFT_MAP, it repeatedly merges (*w_ptr)->reducer_map
 118  * into LEFT_MAP.  This procedure ensures that any new reducers
 119  * created by the reductions themselves also get merged into LEFT_MAP.
 120  */
 121 extern
 122 cilkred_map *repeated_merge_reducer_maps(__cilkrts_worker **w_ptr,
 123                                          cilkred_map *left_map,
 124                                          cilkred_map *right_map);
 125
 126 __CILKRTS_END_EXTERN_C
 127
 128 #endif // ! defined(INCLUDED_REDUCER_IMPL_DOT_H)