Fix incorrect rvdw on GPU with rvdw<rcoulomb

[gromacs.git] / src / gromacs / mdlib / nbnxn_gpu_common.h

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/*! \internal \file
 * \brief Common functions for the different NBNXN GPU implementations.
 *
 * \author Szilard Pall <pall.szilard@gmail.com>
 *
 * \ingroup module_mdlib
 */

#ifndef GMX_MDLIB_NBNXN_GPU_COMMON_H
#define GMX_MDLIB_NBNXN_GPU_COMMON_H

#include "config.h"

#include <string>

#if GMX_GPU == GMX_GPU_CUDA
#include "nbnxn_cuda/nbnxn_cuda_types.h"
#endif

#if GMX_GPU == GMX_GPU_OPENCL
#include "nbnxn_ocl/nbnxn_ocl_types.h"
#endif

#include "gromacs/gpu_utils/gpu_utils.h"
#include "gromacs/math/vec.h"
#include "gromacs/mdlib/force_flags.h"
#include "gromacs/mdlib/nb_verlet.h"
#include "gromacs/mdlib/nbnxn_gpu_types.h"
#include "gromacs/pbcutil/ishift.h"
#include "gromacs/timing/gpu_timing.h"
#include "gromacs/utility/fatalerror.h"
#include "gromacs/utility/stringutil.h"

#include "nbnxn_gpu_common_utils.h"

/*! \brief Check that atom locality values are valid for the GPU module.
 *
 *  In the GPU module atom locality "all" is not supported, the local and
 *  non-local ranges are treated separately.
 *
 *  \param[in] atomLocality atom locality specifier
 */
static inline void validateGpuAtomLocality(int atomLocality)
{
    std::string str = gmx::formatString("Invalid atom locality passed (%d); valid here is only "
                                        "local (%d) or nonlocal (%d)", atomLocality, eatLocal, eatNonlocal);

    GMX_ASSERT(LOCAL_OR_NONLOCAL_A(atomLocality), str.c_str());
}

/*! \brief Convert atom locality to interaction locality.
 *
 *  In the current implementation the this is straightforward conversion:
 *  local to local, non-local to non-local.
 *
 *  \param[in] atomLocality Atom locality specifier
 *  \returns                Interaction locality corresponding to the atom locality passed.
 */
static inline int gpuAtomToInteractionLocality(int atomLocality)
{
    validateGpuAtomLocality(atomLocality);

    /* determine interaction locality from atom locality */
    if (LOCAL_A(atomLocality))
    {
        return eintLocal;
    }
    else if (NONLOCAL_A(atomLocality))
    {
        return eintNonlocal;
    }
    else
    {
        gmx_incons("Wrong locality");
    }
}

/*! \brief Calculate atom range and return start index and length.
 *
 * \param[in] atomData Atom descriptor data structure
 * \param[in] atomLocality Atom locality specifier
 * \param[out] atomRangeBegin Starting index of the atom range in the atom data array.
 * \param[out] atomRangeLen Atom range length in the atom data array.
 */
template <typename AtomDataT>
static inline void getGpuAtomRange(const AtomDataT *atomData,
                                   int              atomLocality,
                                   int             *atomRangeBegin,
                                   int             *atomRangeLen)
{
    assert(atomData);
    validateGpuAtomLocality(atomLocality);

    /* calculate the atom data index range based on locality */
    if (LOCAL_A(atomLocality))
    {
        *atomRangeBegin  = 0;
        *atomRangeLen    = atomData->natoms_local;
    }
    else
    {
        *atomRangeBegin  = atomData->natoms_local;
        *atomRangeLen    = atomData->natoms - atomData->natoms_local;
    }
}


/*! \brief Count pruning kernel time if either kernel has been triggered
 *
 *  We do the accounting for either of the two pruning kernel flavors:
 *   - 1st pass prune: ran during the current step (prior to the force kernel);
 *   - rolling prune:  ran at the end of the previous step (prior to the current step H2D xq);
 *
 * Note that the resetting of cu_timers_t::didPrune and cu_timers_t::didRollingPrune should happen
 * after calling this function.
 *
 * \param[in] timers   structs with GPU timer objects
 * \param[inout] timings  GPU task timing data
 * \param[in] iloc        interaction locality
 */
template <typename GpuTimers>
static void countPruneKernelTime(GpuTimers                 *timers,
                                 gmx_wallclock_gpu_nbnxn_t *timings,
                                 const int                  iloc)
{
    // We might have not done any pruning (e.g. if we skipped with empty domains).
    if (!timers->didPrune[iloc] && !timers->didRollingPrune[iloc])
    {
        return;
    }

    if (timers->didPrune[iloc])
    {
        timings->pruneTime.c++;
        timings->pruneTime.t += timers->prune_k[iloc].getLastRangeTime();
    }

    if (timers->didRollingPrune[iloc])
    {
        timings->dynamicPruneTime.c++;
        timings->dynamicPruneTime.t += timers->rollingPrune_k[iloc].getLastRangeTime();
    }
}

/*! \brief Reduce data staged internally in the nbnxn module.
 *
 * Shift forces and electrostatic/LJ energies copied from the GPU into
 * a module-internal staging area are immediately reduced (CPU-side buffers passed)
 * after having waited for the transfers' completion.
 *
 * Note that this function should always be called after the transfers into the
 * staging buffers has completed.
 *
 * \tparam     StagingData    Type of staging data
 * \param[in]  nbst           Nonbonded staging data
 * \param[in]  iLocality      Interaction locality specifier
 * \param[in]  reduceEnergies True if energy reduction should be done
 * \param[in]  reduceFshift   True if shift force reduction should be done
 * \param[out] e_lj           Variable to accumulate LJ energy into
 * \param[out] e_el           Variable to accumulate electrostatic energy into
 * \param[out] fshift         Pointer to the array of shift forces to accumulate into
 */
template <typename StagingData>
static inline void nbnxn_gpu_reduce_staged_outputs(const StagingData &nbst,
                                                   int                iLocality,
                                                   bool               reduceEnergies,
                                                   bool               reduceFshift,
                                                   real              *e_lj,
                                                   real              *e_el,
                                                   rvec              *fshift)
{
    /* add up energies and shift forces (only once at local F wait) */
    if (LOCAL_I(iLocality))
    {
        if (reduceEnergies)
        {
            *e_lj += *nbst.e_lj;
            *e_el += *nbst.e_el;
        }

        if (reduceFshift)
        {
            for (int i = 0; i < SHIFTS; i++)
            {
                rvec_inc(fshift[i], nbst.fshift[i]);
            }
        }
    }
}

/*! \brief Do the per-step timing accounting of the nonbonded tasks.
 *
 *  Does timing accumulation and call-count increments for the nonbonded kernels.
 *  Note that this function should be called after the current step's nonbonded
 *  nonbonded tasks have completed with the exception of the rolling pruning kernels
 *  that are accounted for during the following step.
 *
 * NOTE: if timing with multiple GPUs (streams) becomes possible, the
 *      counters could end up being inconsistent due to not being incremented
 *      on some of the node when this is skipped on empty local domains!
 *
 * \tparam     GpuTimers         GPU timers type
 * \tparam     GpuPairlist       Pair list type
 * \param[out] timings           Pointer to the NB GPU timings data
 * \param[in]  timers            Pointer to GPU timers data
 * \param[in]  plist             Pointer to the pair list data
 * \param[in]  atomLocality      Atom locality specifier
 * \param[in]  didEnergyKernels  True if energy kernels have been called in the current step
 * \param[in]  doTiming          True if timing is enabled.
 *
 */
template <typename GpuTimers, typename GpuPairlist>
static inline void nbnxn_gpu_accumulate_timings(gmx_wallclock_gpu_nbnxn_t *timings,
                                                GpuTimers                 *timers,
                                                const GpuPairlist         *plist,
                                                int                        atomLocality,
                                                bool                       didEnergyKernels,
                                                bool                       doTiming)
{
    /* timing data accumulation */
    if (!doTiming)
    {
        return;
    }

    /* determine interaction locality from atom locality */
    int iLocality = gpuAtomToInteractionLocality(atomLocality);

    /* only increase counter once (at local F wait) */
    if (LOCAL_I(iLocality))
    {
        timings->nb_c++;
        timings->ktime[plist->haveFreshList ? 1 : 0][didEnergyKernels ? 1 : 0].c += 1;
    }

    /* kernel timings */
    timings->ktime[plist->haveFreshList ? 1 : 0][didEnergyKernels ? 1 : 0].t +=
        timers->nb_k[iLocality].getLastRangeTime();

    /* X/q H2D and F D2H timings */
    timings->nb_h2d_t += timers->nb_h2d[iLocality].getLastRangeTime();
    timings->nb_d2h_t += timers->nb_d2h[iLocality].getLastRangeTime();

    /* Count the pruning kernel times for both cases:1st pass (at search step)
       and rolling pruning (if called at the previous step).
       We do the accounting here as this is the only sync point where we
       know (without checking or additional sync-ing) that prune tasks in
       in the current stream have completed (having just blocking-waited
       for the force D2H). */
    countPruneKernelTime(timers, timings, iLocality);

    /* only count atdat and pair-list H2D at pair-search step */
    if (timers->didPairlistH2D[iLocality])
    {
        /* atdat transfer timing (add only once, at local F wait) */
        if (LOCAL_A(atomLocality))
        {
            timings->pl_h2d_c++;
            timings->pl_h2d_t += timers->atdat.getLastRangeTime();
        }

        timings->pl_h2d_t += timers->pl_h2d[iLocality].getLastRangeTime();

        /* Clear the timing flag for the next step */
        timers->didPairlistH2D[iLocality] = false;
    }
}

//TODO: move into shared source file with gmx_compile_cpp_as_cuda
//NOLINTNEXTLINE(misc-definitions-in-headers)
bool nbnxn_gpu_try_finish_task(gmx_nbnxn_gpu_t  *nb,
                               int               flags,
                               int               aloc,
                               bool              haveOtherWork,
                               real             *e_lj,
                               real             *e_el,
                               rvec             *fshift,
                               GpuTaskCompletion completionKind)
{
    /* determine interaction locality from atom locality */
    int iLocality = gpuAtomToInteractionLocality(aloc);

    //  We skip when during the non-local phase there was actually no work to do.
    //  This is consistent with nbnxn_gpu_launch_kernel.
    if (haveOtherWork || !canSkipWork(nb, iLocality))
    {
        // Query the state of the GPU stream and return early if we're not done
        if (completionKind == GpuTaskCompletion::Check)
        {
            if (!haveStreamTasksCompleted(nb->stream[iLocality]))
            {
                // Early return to skip the steps below that we have to do only
                // after the NB task completed
                return false;
            }
        }
        else
        {
            gpuStreamSynchronize(nb->stream[iLocality]);
        }

        bool calcEner   = (flags & GMX_FORCE_ENERGY) != 0;
        bool calcFshift = (flags & GMX_FORCE_VIRIAL) != 0;

        nbnxn_gpu_accumulate_timings(nb->timings, nb->timers, nb->plist[iLocality], aloc, calcEner,
                                     nb->bDoTime != 0);

        nbnxn_gpu_reduce_staged_outputs(nb->nbst, iLocality, calcEner, calcFshift, e_lj, e_el, fshift);
    }

    /* Always reset both pruning flags (doesn't hurt doing it even when timing is off). */
    nb->timers->didPrune[iLocality] = nb->timers->didRollingPrune[iLocality] = false;

    /* Turn off initial list pruning (doesn't hurt if this is not pair-search step). */
    nb->plist[iLocality]->haveFreshList = false;

    return true;
}

/*! \brief
 * Wait for the asynchronously launched nonbonded tasks and data
 * transfers to finish.
 *
 * Also does timing accounting and reduction of the internal staging buffers.
 * As this is called at the end of the step, it also resets the pair list and
 * pruning flags.
 *
 * \param[in] nb The nonbonded data GPU structure
 * \param[in] flags Force flags
 * \param[in] aloc Atom locality identifier
 * \param[in] haveOtherWork  Tells whether there is other work than non-bonded work in the nbnxn stream(s)
 * \param[out] e_lj Pointer to the LJ energy output to accumulate into
 * \param[out] e_el Pointer to the electrostatics energy output to accumulate into
 * \param[out] fshift Pointer to the shift force buffer to accumulate into
 */
//NOLINTNEXTLINE(misc-definitions-in-headers) TODO: move into source file
void nbnxn_gpu_wait_finish_task(gmx_nbnxn_gpu_t *nb,
                                int              flags,
                                int              aloc,
                                bool             haveOtherWork,
                                real            *e_lj,
                                real            *e_el,
                                rvec            *fshift)
{
    nbnxn_gpu_try_finish_task(nb, flags, aloc, haveOtherWork, e_lj, e_el, fshift,
                              GpuTaskCompletion::Wait);
}

#endif