2 This source code file is part of thread_mpi.
3 Written by Sander Pronk, Erik Lindahl, and possibly others.
5 Copyright (c) 2009, Sander Pronk, Erik Lindahl.
8 Redistribution and use in source and binary forms, with or without
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19 THIS SOFTWARE IS PROVIDED BY US ''AS IS'' AND ANY
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25 LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
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30 If you want to redistribute modifications, please consider that
31 scientific software is very special. Version control is crucial -
32 bugs must be traceable. We will be happy to consider code for
33 inclusion in the official distribution, but derived work should not
34 be called official thread_mpi. Details are found in the README & COPYING
42 #ifndef TMPI_WAIT_FOR_NO_ONE
44 #if !(defined( _WIN32 ) || defined( _WIN64 ) )
52 /* for now we just do sched_yield(). It's in POSIX. */
53 /* the data associated with waiting. */
54 #define TMPI_YIELD_WAIT_DATA
55 /* the initialization associated with waiting. */
56 #define TMPI_YIELD_WAIT_DATA_INIT(data)
58 /* the waiting macro */
59 #define TMPI_YIELD_WAIT(data) sched_yield()
62 /* and in Windows, we do SwitchToThread() alternated with Sleep(0). This
63 is apparently recommende practice (SwitchToThread() alone just gives
64 up the slice for threads on the current core, and Sleep(0) alone could
65 lead to starvation. This mixed approach actually gives better real-world
66 performance in the test program.*/
67 /* the data associated with waiting. */
68 #define TMPI_YIELD_WAIT_DATA int yield_wait_counter;
69 /* the initialization associated with waiting. */
70 #define TMPI_YIELD_WAIT_DATA_INIT(data) { (data)->yield_wait_counter = 0; }
72 /* the waiting macro is so complicated because using SwitchToThread only schedules */
73 #define TMPI_YIELD_WAIT(data) { \
74 if ( ((data)->yield_wait_counter++)%100 == 0) \
87 #else /* !TMPI_WAIT_FOR_NO_ONE */
89 /* the data associated with waiting. */
90 #define TMPI_YIELD_WAIT_DATA
91 /* the initialization associated with waiting. */
92 #define TMPI_YIELD_WAIT_DATA_INIT(data)
94 /* the waiting macro */
95 #define TMPI_YIELD_WAIT(data) tMPI_Atomic_memory_barrier()
98 #endif /* !TMPI_WAIT_FOR_NO_ONE */
100 #endif /* TMPI_WAIT_H_ */