libcilkrts/runtime/signal_node.h

   1 /* signal_node.h                  -*-C++-*-
   2  *
   3  *************************************************************************
   4  *
   5  *  @copyright
   6  *  Copyright (C) 2009-2013, Intel Corporation
   7  *  All rights reserved.
   8  *
   9  *  @copyright
  10  *  Redistribution and use in source and binary forms, with or without
  11  *  modification, are permitted provided that the following conditions
  12  *  are met:
  13  *
  14  *    * Redistributions of source code must retain the above copyright
  15  *      notice, this list of conditions and the following disclaimer.
  16  *    * Redistributions in binary form must reproduce the above copyright
  17  *      notice, this list of conditions and the following disclaimer in
  18  *      the documentation and/or other materials provided with the
  19  *      distribution.
  20  *    * Neither the name of Intel Corporation nor the names of its
  21  *      contributors may be used to endorse or promote products derived
  22  *      from this software without specific prior written permission.
  23  *
  24  *  @copyright
  25  *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  28  *  A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  29  *  HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  30  *  INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  31  *  BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
  32  *  OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  33  *  AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  34  *  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
  35  *  WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  36  *  POSSIBILITY OF SUCH DAMAGE.
  37  **************************************************************************/
  38
  39 /**
  40  * @file signal_node.h
  41  *
  42  * @brief Signal nodes allow coordinated waking and sleeping of the runtime
  43  * without hammering on a single location in memory.
  44  *
  45  * The workers are logically arranged in a binary tree and propagate messages
  46  * leaf-ward.  User workers notify the root about waking and sleeping, so only
  47  * that one node need share a cache line with a user worker.
  48  */
  49
  50 #ifndef INCLUDED_SIGNAL_NODE_DOT_H
  51 #define INCLUDED_SIGNAL_NODE_DOT_H
  52
  53 #include "rts-common.h"
  54 #include <cilk/common.h>
  55
  56 __CILKRTS_BEGIN_EXTERN_C
  57
  58 /** Opaque type. */
  59 typedef struct signal_node_t signal_node_t;
  60
  61 /**
  62  * Allocate and initialize a signal_node_t
  63  *
  64  * @return The initialized signal_node_t
  65  */
  66 COMMON_SYSDEP
  67 signal_node_t *signal_node_create(void);
  68
  69 /**
  70  * Free any resources and deallocate a signal_node_t
  71  *
  72  * @param node The node to be deallocated.
  73  */
  74 COMMON_SYSDEP void signal_node_destroy(signal_node_t *node);
  75
  76 /**
  77  * Test whether the node thinks the worker should go to sleep
  78  *
  79  * @param node The node to be tested.
  80  *
  81  * @return 1 If the worker should go to sleep
  82  * @return 0 If the worker should not go to sleep
  83  */
  84 COMMON_SYSDEP
  85 unsigned int signal_node_should_wait(signal_node_t *node);
  86
  87 /**
  88  * Specify whether the worker should go to sleep
  89  *
  90  * @param node The node to be set.
  91  * @param msg The value to be set.  Valid values are:
  92  * - 0 - the worker should go to sleep
  93  * - 1 - the worker should stay active
  94  */
  95 COMMON_SYSDEP
  96 void signal_node_msg(signal_node_t *node, unsigned int msg);
  97
  98
  99 /**
 100  * Wait for the node to be set
 101  *
 102  * @param node The node to wait on
 103  */
 104 COMMON_SYSDEP
 105 void signal_node_wait(signal_node_t *node);
 106
 107 __CILKRTS_END_EXTERN_C
 108
 109 #endif // ! defined(INCLUDED_SIGNAL_NODE_DOT_H)