src/gromacs/ewald/pme_gpu.cpp

   1 /*
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   3  *
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  35
  36 /*! \internal \file
  37  * \brief Implements high-level PME GPU functions which do not require GPU framework-specific code.
  38  *
  39  * \author Aleksei Iupinov <a.yupinov@gmail.com>
  40  * \ingroup module_ewald
  41  */
  42
  43 #include "gmxpre.h"
  44
  45 #include "config.h"
  46
  47 #include <list>
  48
  49 #include "gromacs/ewald/ewald_utils.h"
  50 #include "gromacs/ewald/pme.h"
  51 #include "gromacs/fft/parallel_3dfft.h"
  52 #include "gromacs/math/invertmatrix.h"
  53 #include "gromacs/mdlib/gmx_omp_nthreads.h"
  54 #include "gromacs/mdtypes/enerdata.h"
  55 #include "gromacs/mdtypes/forceoutput.h"
  56 #include "gromacs/mdtypes/inputrec.h"
  57 #include "gromacs/utility/exceptions.h"
  58 #include "gromacs/utility/fatalerror.h"
  59 #include "gromacs/utility/gmxassert.h"
  60 #include "gromacs/utility/stringutil.h"
  61
  62 #include "pme_gpu_internal.h"
  63 #include "pme_grid.h"
  64 #include "pme_internal.h"
  65 #include "pme_solve.h"
  66
  67 void pme_gpu_reset_timings(const gmx_pme_t *pme)
  68 {
  69     if (pme_gpu_active(pme))
  70     {
  71         pme_gpu_reset_timings(pme->gpu);
  72     }
  73 }
  74
  75 void pme_gpu_get_timings(const gmx_pme_t *pme, gmx_wallclock_gpu_pme_t *timings)
  76 {
  77     if (pme_gpu_active(pme))
  78     {
  79         pme_gpu_get_timings(pme->gpu, timings);
  80     }
  81 }
  82
  83 int pme_gpu_get_padding_size(const gmx_pme_t *pme)
  84 {
  85
  86     if (!pme || !pme_gpu_active(pme))
  87     {
  88         return 0;
  89     }
  90     else
  91     {
  92         return pme_gpu_get_atom_data_alignment(pme->gpu);
  93     }
  94 }
  95
  96 /*! \brief
  97  * A convenience wrapper for launching either the GPU or CPU FFT.
  98  *
  99  * \param[in] pme            The PME structure.
 100  * \param[in] gridIndex      The grid index - should currently always be 0.
 101  * \param[in] dir            The FFT direction enum.
 102  * \param[in] wcycle         The wallclock counter.
 103  */
 104 void inline parallel_3dfft_execute_gpu_wrapper(gmx_pme_t              *pme,
 105                                                const int               gridIndex,
 106                                                enum gmx_fft_direction  dir,
 107                                                gmx_wallcycle_t         wcycle)
 108 {
 109     GMX_ASSERT(gridIndex == 0, "Only single grid supported");
 110     if (pme_gpu_performs_FFT(pme->gpu))
 111     {
 112         wallcycle_start_nocount(wcycle, ewcLAUNCH_GPU);
 113         wallcycle_sub_start_nocount(wcycle, ewcsLAUNCH_GPU_PME);
 114         pme_gpu_3dfft(pme->gpu, dir, gridIndex);
 115         wallcycle_sub_stop(wcycle, ewcsLAUNCH_GPU_PME);
 116         wallcycle_stop(wcycle, ewcLAUNCH_GPU);
 117     }
 118     else
 119     {
 120         wallcycle_start(wcycle, ewcPME_FFT_MIXED_MODE);
 121 #pragma omp parallel for num_threads(pme->nthread) schedule(static)
 122         for (int thread = 0; thread < pme->nthread; thread++)
 123         {
 124             gmx_parallel_3dfft_execute(pme->pfft_setup[gridIndex], dir, thread, wcycle);
 125         }
 126         wallcycle_stop(wcycle, ewcPME_FFT_MIXED_MODE);
 127     }
 128 }
 129
 130 /* The PME computation code split into a few separate functions. */
 131
 132 void pme_gpu_prepare_computation(gmx_pme_t            *pme,
 133                                  bool                  needToUpdateBox,
 134                                  const matrix          box,
 135                                  gmx_wallcycle        *wcycle,
 136                                  int                   flags,
 137                                  bool                  useGpuForceReduction)
 138 {
 139     GMX_ASSERT(pme_gpu_active(pme), "This should be a GPU run of PME but it is not enabled.");
 140     GMX_ASSERT(pme->nnodes > 0, "");
 141     GMX_ASSERT(pme->nnodes == 1 || pme->ndecompdim > 0, "");
 142
 143     PmeGpu *pmeGpu = pme->gpu;
 144     pmeGpu->settings.currentFlags         = flags;
 145     // TODO these flags are only here to honor the CPU PME code, and probably should be removed
 146     pmeGpu->settings.useGpuForceReduction = useGpuForceReduction;
 147
 148     bool shouldUpdateBox = false;
 149     for (int i = 0; i < DIM; ++i)
 150     {
 151         for (int j = 0; j <= i; ++j)
 152         {
 153             shouldUpdateBox                  |= (pmeGpu->common->previousBox[i][j] != box[i][j]);
 154             pmeGpu->common->previousBox[i][j] = box[i][j];
 155         }
 156     }
 157
 158     if (needToUpdateBox || shouldUpdateBox) // || is to make the first computation always update
 159     {
 160         wallcycle_start_nocount(wcycle, ewcLAUNCH_GPU);
 161         wallcycle_sub_start_nocount(wcycle, ewcsLAUNCH_GPU_PME);
 162         pme_gpu_update_input_box(pmeGpu, box);
 163         wallcycle_sub_stop(wcycle, ewcsLAUNCH_GPU_PME);
 164         wallcycle_stop(wcycle, ewcLAUNCH_GPU);
 165
 166         if (!pme_gpu_performs_solve(pmeGpu))
 167         {
 168             // TODO remove code duplication and add test coverage
 169             matrix scaledBox;
 170             pmeGpu->common->boxScaler->scaleBox(box, scaledBox);
 171             gmx::invertBoxMatrix(scaledBox, pme->recipbox);
 172             pme->boxVolume = scaledBox[XX][XX] * scaledBox[YY][YY] * scaledBox[ZZ][ZZ];
 173         }
 174     }
 175 }
 176
 177 void pme_gpu_copy_coordinates_to_gpu(gmx_pme_t            *pme,
 178                                      const rvec           *coordinatesHost,
 179                                      gmx_wallcycle        *wcycle)
 180 {
 181     GMX_ASSERT(pme_gpu_active(pme), "This should be a GPU run of PME but it is not enabled.");
 182
 183     PmeGpu *pmeGpu = pme->gpu;
 184
 185     // The only spot of PME GPU where LAUNCH_GPU counter increases call-count
 186     wallcycle_start(wcycle, ewcLAUNCH_GPU);
 187     // The only spot of PME GPU where ewcsLAUNCH_GPU_PME subcounter increases call-count
 188     wallcycle_sub_start(wcycle, ewcsLAUNCH_GPU_PME);
 189     pme_gpu_copy_input_coordinates(pmeGpu, coordinatesHost);
 190     wallcycle_sub_stop(wcycle, ewcsLAUNCH_GPU_PME);
 191     wallcycle_stop(wcycle, ewcLAUNCH_GPU);
 192 }
 193
 194 void pme_gpu_launch_spread(gmx_pme_t            *pme,
 195                            gmx_wallcycle        *wcycle)
 196 {
 197     GMX_ASSERT(pme_gpu_active(pme), "This should be a GPU run of PME but it is not enabled.");
 198
 199     PmeGpu            *pmeGpu = pme->gpu;
 200
 201     const unsigned int gridIndex  = 0;
 202     real              *fftgrid    = pme->fftgrid[gridIndex];
 203     if (pmeGpu->settings.currentFlags & GMX_PME_SPREAD)
 204     {
 205         /* Spread the coefficients on a grid */
 206         const bool computeSplines = true;
 207         const bool spreadCharges  = true;
 208         wallcycle_start_nocount(wcycle, ewcLAUNCH_GPU);
 209         wallcycle_sub_start_nocount(wcycle, ewcsLAUNCH_GPU_PME);
 210         pme_gpu_spread(pmeGpu, gridIndex, fftgrid, computeSplines, spreadCharges);
 211         wallcycle_sub_stop(wcycle, ewcsLAUNCH_GPU_PME);
 212         wallcycle_stop(wcycle, ewcLAUNCH_GPU);
 213     }
 214 }
 215
 216 void pme_gpu_launch_complex_transforms(gmx_pme_t      *pme,
 217                                        gmx_wallcycle  *wcycle)
 218 {
 219     PmeGpu            *pmeGpu                 = pme->gpu;
 220     const bool         computeEnergyAndVirial = (pmeGpu->settings.currentFlags & GMX_PME_CALC_ENER_VIR) != 0;
 221     const bool         performBackFFT         = (pmeGpu->settings.currentFlags & (GMX_PME_CALC_F | GMX_PME_CALC_POT)) != 0;
 222     const unsigned int gridIndex              = 0;
 223     t_complex         *cfftgrid               = pme->cfftgrid[gridIndex];
 224
 225     if (pmeGpu->settings.currentFlags & GMX_PME_SPREAD)
 226     {
 227         if (!pme_gpu_performs_FFT(pmeGpu))
 228         {
 229             wallcycle_start(wcycle, ewcWAIT_GPU_PME_SPREAD);
 230             pme_gpu_sync_spread_grid(pme->gpu);
 231             wallcycle_stop(wcycle, ewcWAIT_GPU_PME_SPREAD);
 232         }
 233     }
 234
 235     try
 236     {
 237         if (pmeGpu->settings.currentFlags & GMX_PME_SOLVE)
 238         {
 239             /* do R2C 3D-FFT */
 240             parallel_3dfft_execute_gpu_wrapper(pme, gridIndex, GMX_FFT_REAL_TO_COMPLEX, wcycle);
 241
 242             /* solve in k-space for our local cells */
 243             if (pme_gpu_performs_solve(pmeGpu))
 244             {
 245                 const auto gridOrdering = pme_gpu_uses_dd(pmeGpu) ? GridOrdering::YZX : GridOrdering::XYZ;
 246                 wallcycle_start_nocount(wcycle, ewcLAUNCH_GPU);
 247                 wallcycle_sub_start_nocount(wcycle, ewcsLAUNCH_GPU_PME);
 248                 pme_gpu_solve(pmeGpu, cfftgrid, gridOrdering, computeEnergyAndVirial);
 249                 wallcycle_sub_stop(wcycle, ewcsLAUNCH_GPU_PME);
 250                 wallcycle_stop(wcycle, ewcLAUNCH_GPU);
 251             }
 252             else
 253             {
 254                 wallcycle_start(wcycle, ewcPME_SOLVE_MIXED_MODE);
 255 #pragma omp parallel for num_threads(pme->nthread) schedule(static)
 256                 for (int thread = 0; thread < pme->nthread; thread++)
 257                 {
 258                     solve_pme_yzx(pme, cfftgrid, pme->boxVolume,
 259                                   computeEnergyAndVirial, pme->nthread, thread);
 260                 }
 261                 wallcycle_stop(wcycle, ewcPME_SOLVE_MIXED_MODE);
 262             }
 263         }
 264
 265         if (performBackFFT)
 266         {
 267             parallel_3dfft_execute_gpu_wrapper(pme, gridIndex, GMX_FFT_COMPLEX_TO_REAL, wcycle);
 268         }
 269     } GMX_CATCH_ALL_AND_EXIT_WITH_FATAL_ERROR;
 270 }
 271
 272 void pme_gpu_launch_gather(const gmx_pme_t                 *pme,
 273                            gmx_wallcycle gmx_unused        *wcycle,
 274                            PmeForceOutputHandling           forceTreatment)
 275 {
 276     GMX_ASSERT(pme_gpu_active(pme), "This should be a GPU run of PME but it is not enabled.");
 277
 278     if (!pme_gpu_performs_gather(pme->gpu))
 279     {
 280         return;
 281     }
 282
 283     wallcycle_start_nocount(wcycle, ewcLAUNCH_GPU);
 284     wallcycle_sub_start_nocount(wcycle, ewcsLAUNCH_GPU_PME);
 285     const unsigned int gridIndex  = 0;
 286     real              *fftgrid    = pme->fftgrid[gridIndex];
 287     pme_gpu_gather(pme->gpu, forceTreatment, reinterpret_cast<float *>(fftgrid));
 288     wallcycle_sub_stop(wcycle, ewcsLAUNCH_GPU_PME);
 289     wallcycle_stop(wcycle, ewcLAUNCH_GPU);
 290 }
 291
 292 //! Accumulate the \c forcesToAdd to \c f, using the available threads.
 293 static void sum_forces(gmx::ArrayRef<gmx::RVec>       f,
 294                        gmx::ArrayRef<const gmx::RVec> forceToAdd)
 295 {
 296     const int      end = forceToAdd.size();
 297
 298     int gmx_unused nt = gmx_omp_nthreads_get(emntPME);
 299 #pragma omp parallel for num_threads(nt) schedule(static)
 300     for (int i = 0; i < end; i++)
 301     {
 302         f[i] += forceToAdd[i];
 303     }
 304 }
 305
 306 //! Reduce quantities from \c output to \c forceWithVirial and \c enerd.
 307 static void pme_gpu_reduce_outputs(const int             flags,
 308                                    const PmeOutput      &output,
 309                                    gmx_wallcycle        *wcycle,
 310                                    gmx::ForceWithVirial *forceWithVirial,
 311                                    gmx_enerdata_t       *enerd)
 312 {
 313     wallcycle_start(wcycle, ewcPME_GPU_F_REDUCTION);
 314     GMX_ASSERT(forceWithVirial, "Invalid force pointer");
 315
 316     const bool haveComputedEnergyAndVirial = (flags & GMX_PME_CALC_ENER_VIR) != 0;
 317     if (haveComputedEnergyAndVirial)
 318     {
 319         GMX_ASSERT(enerd, "Invalid energy output manager");
 320         forceWithVirial->addVirialContribution(output.coulombVirial_);
 321         enerd->term[F_COUL_RECIP] += output.coulombEnergy_;
 322     }
 323     if (output.haveForceOutput_)
 324     {
 325         sum_forces(forceWithVirial->force_, output.forces_);
 326     }
 327     wallcycle_stop(wcycle, ewcPME_GPU_F_REDUCTION);
 328 }
 329
 330 bool pme_gpu_try_finish_task(gmx_pme_t            *pme,
 331                              const int             flags,
 332                              gmx_wallcycle        *wcycle,
 333                              gmx::ForceWithVirial *forceWithVirial,
 334                              gmx_enerdata_t       *enerd,
 335                              GpuTaskCompletion     completionKind)
 336 {
 337     GMX_ASSERT(pme_gpu_active(pme), "This should be a GPU run of PME but it is not enabled.");
 338     GMX_ASSERT(!pme->gpu->settings.useGpuForceReduction, "GPU force reduction should not be active on the pme_gpu_try_finish_task() path");
 339
 340     // First, if possible, check whether all tasks on the stream have
 341     // completed, and return fast if not. Accumulate to wcycle the
 342     // time needed for that checking, but do not yet record that the
 343     // gather has occured.
 344     bool           needToSynchronize      = true;
 345     constexpr bool c_streamQuerySupported = (GMX_GPU == GMX_GPU_CUDA);
 346     // TODO: implement c_streamQuerySupported with an additional GpuEventSynchronizer per stream (#2521)
 347     if ((completionKind == GpuTaskCompletion::Check) && c_streamQuerySupported)
 348     {
 349         wallcycle_start_nocount(wcycle, ewcWAIT_GPU_PME_GATHER);
 350         // Query the PME stream for completion of all tasks enqueued and
 351         // if we're not done, stop the timer before early return.
 352         const bool pmeGpuDone = pme_gpu_stream_query(pme->gpu);
 353         wallcycle_stop(wcycle, ewcWAIT_GPU_PME_GATHER);
 354
 355         if (!pmeGpuDone)
 356         {
 357             return false;
 358         }
 359         needToSynchronize = false;
 360     }
 361
 362     wallcycle_start(wcycle, ewcWAIT_GPU_PME_GATHER);
 363     // If the above check passed, then there is no need to make an
 364     // explicit synchronization call.
 365     if (needToSynchronize)
 366     {
 367         // Synchronize the whole PME stream at once, including D2H result transfers.
 368         pme_gpu_synchronize(pme->gpu);
 369     }
 370     pme_gpu_update_timings(pme->gpu);
 371     PmeOutput output = pme_gpu_getOutput(*pme, flags);
 372     wallcycle_stop(wcycle, ewcWAIT_GPU_PME_GATHER);
 373
 374     GMX_ASSERT(pme->gpu->settings.useGpuForceReduction == !output.haveForceOutput_, "When forces are reduced on the CPU, there needs to be force output");
 375     pme_gpu_reduce_outputs(flags, output, wcycle, forceWithVirial, enerd);
 376
 377     return true;
 378 }
 379
 380 // This is used by PME-only ranks
 381 PmeOutput pme_gpu_wait_finish_task(gmx_pme_t     *pme,
 382                                    const int      flags,
 383                                    gmx_wallcycle *wcycle)
 384 {
 385     GMX_ASSERT(pme_gpu_active(pme), "This should be a GPU run of PME but it is not enabled.");
 386
 387     wallcycle_start(wcycle, ewcWAIT_GPU_PME_GATHER);
 388
 389     // Synchronize the whole PME stream at once, including D2H result transfers.
 390     //
 391     // TODO: make this sync conditional to wait only for virial/energies
 392     pme_gpu_synchronize(pme->gpu);
 393
 394     pme_gpu_update_timings(pme->gpu);
 395     PmeOutput output = pme_gpu_getOutput(*pme, flags);
 396     wallcycle_stop(wcycle, ewcWAIT_GPU_PME_GATHER);
 397     return output;
 398 }
 399
 400 // This is used when not using the alternate-waiting reduction
 401 void pme_gpu_wait_and_reduce(gmx_pme_t            *pme,
 402                              const int             flags,
 403                              gmx_wallcycle        *wcycle,
 404                              gmx::ForceWithVirial *forceWithVirial,
 405                              gmx_enerdata_t       *enerd)
 406 {
 407     PmeOutput output = pme_gpu_wait_finish_task(pme, flags, wcycle);
 408     GMX_ASSERT(pme->gpu->settings.useGpuForceReduction == !output.haveForceOutput_, "When forces are reduced on the CPU, there needs to be force output");
 409     pme_gpu_reduce_outputs(flags, output, wcycle, forceWithVirial, enerd);
 410 }
 411
 412 void pme_gpu_reinit_computation(const gmx_pme_t *pme,
 413                                 gmx_wallcycle   *wcycle)
 414 {
 415     GMX_ASSERT(pme_gpu_active(pme), "This should be a GPU run of PME but it is not enabled.");
 416
 417     wallcycle_start_nocount(wcycle, ewcLAUNCH_GPU);
 418     wallcycle_sub_start_nocount(wcycle, ewcsLAUNCH_GPU_PME);
 419
 420     pme_gpu_clear_grids(pme->gpu);
 421     pme_gpu_clear_energy_virial(pme->gpu);
 422
 423     wallcycle_sub_stop(wcycle, ewcsLAUNCH_GPU_PME);
 424     wallcycle_stop(wcycle, ewcLAUNCH_GPU);
 425 }
 426
 427 DeviceBuffer<float> pme_gpu_get_device_x(const gmx_pme_t *pme)
 428 {
 429     GMX_ASSERT((pme && pme_gpu_active(pme)), "PME GPU coordinates buffer was requested from uninitialized PME module");
 430     return pme_gpu_get_kernelparam_coordinates(pme->gpu);
 431 }
 432
 433 void *pme_gpu_get_device_f(const gmx_pme_t *pme)
 434 {
 435     if (!pme || !pme_gpu_active(pme))
 436     {
 437         return nullptr;
 438     }
 439     return pme_gpu_get_kernelparam_forces(pme->gpu);
 440 }
 441
 442 void *pme_gpu_get_device_stream(const gmx_pme_t *pme)
 443 {
 444     if (!pme || !pme_gpu_active(pme))
 445     {
 446         return nullptr;
 447     }
 448     return pme_gpu_get_stream(pme->gpu);
 449 }
 450
 451 GpuEventSynchronizer * pme_gpu_get_f_ready_synchronizer(const gmx_pme_t *pme)
 452 {
 453     if (!pme || !pme_gpu_active(pme))
 454     {
 455         return nullptr;
 456     }
 457
 458     return pme_gpu_get_forces_ready_synchronizer(pme->gpu);
 459 }