src/gromacs/taskassignment/decidegpuusage.h

   1 /*
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   5  * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
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  35 /*! \libinternal \file
  36  * \brief Declares functionality for deciding whether tasks will run on GPUs.
  37  *
  38  * \author Mark Abraham <mark.j.abraham@gmail.com>
  39  * \ingroup module_taskassignment
  40  * \inlibraryapi
  41  */
  42
  43 #ifndef GMX_TASKASSIGNMENT_DECIDEGPUUSAGE_H
  44 #define GMX_TASKASSIGNMENT_DECIDEGPUUSAGE_H
  45
  46 #include <vector>
  47
  48 struct gmx_hw_info_t;
  49
  50 enum class EmulateGpuNonbonded : bool;
  51
  52 namespace gmx
  53 {
  54
  55 //! Record where a compute task is targetted.
  56 enum class TaskTarget : int
  57 {
  58     Auto,
  59     Cpu,
  60     Gpu
  61 };
  62
  63 /*! \brief Decide whether this thread-MPI simulation will run
  64  * nonbonded tasks on GPUs.
  65  *
  66  * The number of GPU tasks and devices influences both the choice of
  67  * the number of ranks, and checks upon any such choice made by the
  68  * user. So we need to consider this before any automated choice of
  69  * the number of thread-MPI ranks.
  70  *
  71  * \param[in]  nonbondedTarget           The user's choice for mdrun -nb for where to assign short-ranged nonbonded interaction tasks.
  72  * \param[in]  gpuIdsToUse               The compatible GPUs that the user permitted us to use.
  73  * \param[in]  userGpuTaskAssignment     The user-specified assignment of GPU tasks to device IDs.
  74  * \param[in]  emulateGpuNonbonded       Whether we will emulate GPU calculation of nonbonded interactions.
  75  * \param[in]  usingVerletScheme         Whether the nonbondeds are using the Verlet scheme.
  76  * \param[in]  nonbondedOnGpuIsUseful    Whether computing nonbonded interactions on a GPU is useful for this calculation.
  77  * \param[in]  numRanksPerSimulation     The number of ranks in each simulation.
  78  *
  79  * \returns    Whether the simulation will run nonbonded tasks on GPUs.
  80  *
  81  * \throws     std::bad_alloc          If out of memory
  82  *             InconsistentInputError  If the user requirements are inconsistent. */
  83 bool decideWhetherToUseGpusForNonbondedWithThreadMpi(const TaskTarget          nonbondedTarget,
  84                                                      const std::vector<int>   &gpuIdsToUse,
  85                                                      const std::vector<int>   &userGpuTaskAssignment,
  86                                                      const EmulateGpuNonbonded emulateGpuNonbonded,
  87                                                      const bool                usingVerletScheme,
  88                                                      const bool                nonbondedOnGpuIsUseful,
  89                                                      const int                 numRanksPerSimulation);
  90
  91 /*! \brief Decide whether this thread-MPI simulation will run
  92  * PME tasks on GPUs.
  93  *
  94  * The number of GPU tasks and devices influences both the choice of
  95  * the number of ranks, and checks upon any such choice made by the
  96  * user. So we need to consider this before any automated choice of
  97  * the number of thread-MPI ranks.
  98  *
  99  * \param[in]  useGpuForNonbonded        Whether GPUs will be used for nonbonded interactions.
 100  * \param[in]  pmeTarget                 The user's choice for mdrun -pme for where to assign long-ranged PME nonbonded interaction tasks.
 101  * \param[in]  gpuIdsToUse               The compatible GPUs that the user permitted us to use.
 102  * \param[in]  userGpuTaskAssignment     The user-specified assignment of GPU tasks to device IDs.
 103  * \param[in]  canUseGpuForPme           Whether the form of PME chosen can run on a GPU
 104  * \param[in]  numRanksPerSimulation     The number of ranks in each simulation.
 105  *
 106  * \returns    Whether the simulation will run PME tasks on GPUs.
 107  *
 108  * \throws     std::bad_alloc          If out of memory
 109  *             InconsistentInputError  If the user requirements are inconsistent. */
 110 bool decideWhetherToUseGpusForPmeWithThreadMpi(const bool              useGpuForNonbonded,
 111                                                const TaskTarget        pmeTarget,
 112                                                const std::vector<int> &gpuIdsToUse,
 113                                                const std::vector<int> &userGpuTaskAssignment,
 114                                                const bool              canUseGpuForPme,
 115                                                const int               numRanksPerSimulation);
 116
 117 /*! \brief Decide whether the simulation will try to run nonbonded
 118  * tasks on GPUs.
 119  *
 120  * The final decision cannot be made until after the duty of the rank
 121  * is known. But we need to know if nonbonded will run on GPUs for
 122  * setting up DD (particularly rlist) and determining duty. If the
 123  * user requires GPUs for the tasks of that duty, then it will be an
 124  * error when none are found.
 125  *
 126  * With thread-MPI, calls have been made to
 127  * decideWhetherToUseGpusForNonbondedWithThreadMpi() and
 128  * decideWhetherToUseGpusForPmeWithThreadMpi() to help determine
 129  * the number of ranks and run some checks, but the final
 130  * decision is made in this routine, along with many more
 131  * consistency checks.
 132  *
 133  * \param[in]  nonbondedTarget           The user's choice for mdrun -nb for where to assign short-ranged nonbonded interaction tasks.
 134  * \param[in]  gpuIdsToUse               The compatible GPUs that the user permitted us to use.
 135  * \param[in]  userGpuTaskAssignment     The user-specified assignment of GPU tasks to device IDs.
 136  * \param[in]  emulateGpuNonbonded       Whether we will emulate GPU calculation of nonbonded interactions.
 137  * \param[in]  usingVerletScheme         Whether the nonbondeds are using the Verlet scheme.
 138  * \param[in]  nonbondedOnGpuIsUseful    Whether computing nonbonded interactions on a GPU is useful for this calculation.
 139  *
 140  * \returns    Whether the simulation will run nonbonded and PME tasks, respectively, on GPUs.
 141  *
 142  * \throws     std::bad_alloc          If out of memory
 143  *             InconsistentInputError  If the user requirements are inconsistent. */
 144 bool decideWhetherToUseGpusForNonbonded(const TaskTarget           nonbondedTarget,
 145                                         const std::vector<int>    &gpuIdsToUse,
 146                                         const std::vector<int>    &userGpuTaskAssignment,
 147                                         const EmulateGpuNonbonded  emulateGpuNonbonded,
 148                                         const bool                 usingVerletScheme,
 149                                         const bool                 nonbondedOnGpuIsUseful);
 150
 151 /*! \brief Decide whether the simulation will try to run tasks of
 152  * different types on GPUs.
 153  *
 154  * The final decision cannot be made until after the duty of the rank
 155  * is known. But we need to know if nonbonded will run on GPUs for
 156  * setting up DD (particularly rlist) and determining duty. If the
 157  * user requires GPUs for the tasks of that duty, then it will be an
 158  * error when none are found.
 159  *
 160  * With thread-MPI, calls have been made to
 161  * decideWhetherToUseGpusForNonbondedWithThreadMpi() and
 162  * decideWhetherToUseGpusForPmeWithThreadMpi() to help determine
 163  * the number of ranks and run some checks, but the final
 164  * decision is made in this routine, along with many more
 165  * consistency checks.
 166  *
 167  * \param[in]  useGpuForNonbonded        Whether GPUs will be used for nonbonded interactions.
 168  * \param[in]  pmeTarget                 The user's choice for mdrun -pme for where to assign long-ranged PME nonbonded interaction tasks.
 169  * \param[in]  userGpuTaskAssignment     The user-specified assignment of GPU tasks to device IDs.
 170  * \param[in]  canUseGpuForPme           Whether the form of PME chosen can run on a GPU
 171  * \param[in]  numRanksPerSimulation     The number of ranks in each simulation.
 172  *
 173  * \returns    Whether the simulation will run nonbonded and PME tasks, respectively, on GPUs.
 174  *
 175  * \throws     std::bad_alloc          If out of memory
 176  *             InconsistentInputError  If the user requirements are inconsistent. */
 177 bool decideWhetherToUseGpusForPme(const bool              useGpuForNonbonded,
 178                                   const TaskTarget        pmeTarget,
 179                                   const std::vector<int> &userGpuTaskAssignment,
 180                                   const bool              canUseGpuForPme,
 181                                   const int               numRanksPerSimulation);
 182
 183 }
 184
 185 #endif