src/gromacs/ewald/pme_pp.cpp

   1 /*
   2  * This file is part of the GROMACS molecular simulation package.
   3  *
   4  * Copyright (c) 1991-2000, University of Groningen, The Netherlands.
   5  * Copyright (c) 2001-2004, The GROMACS development team.
   6  * Copyright (c) 2013,2014,2015,2016,2017 by the GROMACS development team.
   7  * Copyright (c) 2018,2019,2020,2021, by the GROMACS development team, led by
   8  * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
   9  * and including many others, as listed in the AUTHORS file in the
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  38 /*! \internal \file
  39  *
  40  * \brief This file contains function definitions necessary for
  41  * managing the offload of long-ranged PME work to separate MPI rank,
  42  * for computing energies and forces (Coulomb and LJ).
  43  *
  44  * \author Berk Hess <hess@kth.se>
  45  * \ingroup module_ewald
  46  */
  47
  48 #include "gmxpre.h"
  49
  50 #include "pme_pp.h"
  51
  52 #include "config.h"
  53
  54 #include <cstdio>
  55 #include <cstring>
  56
  57 #include "gromacs/domdec/domdec.h"
  58 #include "gromacs/domdec/domdec_struct.h"
  59 #include "gromacs/ewald/pme.h"
  60 #include "gromacs/ewald/pme_pp_comm_gpu.h"
  61 #include "gromacs/gmxlib/network.h"
  62 #include "gromacs/math/vec.h"
  63 #include "gromacs/mdlib/gmx_omp_nthreads.h"
  64 #include "gromacs/mdtypes/commrec.h"
  65 #include "gromacs/mdtypes/forceoutput.h"
  66 #include "gromacs/mdtypes/forcerec.h"
  67 #include "gromacs/mdtypes/interaction_const.h"
  68 #include "gromacs/mdtypes/md_enums.h"
  69 #include "gromacs/mdtypes/state_propagator_data_gpu.h"
  70 #include "gromacs/nbnxm/nbnxm.h"
  71 #include "gromacs/timing/wallcycle.h"
  72 #include "gromacs/utility/fatalerror.h"
  73 #include "gromacs/utility/gmxmpi.h"
  74 #include "gromacs/utility/smalloc.h"
  75
  76 #include "pme_pp_communication.h"
  77
  78 /*! \brief Block to wait for communication to PME ranks to complete
  79  *
  80  * This should be faster with a real non-blocking MPI implementation
  81  */
  82 static constexpr bool c_useDelayedWait = false;
  83
  84 /*! \brief Wait for the pending data send requests to PME ranks to complete */
  85 static void gmx_pme_send_coeffs_coords_wait(gmx_domdec_t* dd)
  86 {
  87     if (dd->nreq_pme)
  88     {
  89 #if GMX_MPI
  90         MPI_Waitall(dd->nreq_pme, dd->req_pme, MPI_STATUSES_IGNORE);
  91 #endif
  92         dd->nreq_pme = 0;
  93     }
  94 }
  95
  96 /*! \brief Send data to PME ranks */
  97 static void gmx_pme_send_coeffs_coords(t_forcerec*         fr,
  98                                        const t_commrec*    cr,
  99                                        unsigned int        flags,
 100                                        gmx::ArrayRef<real> chargeA,
 101                                        gmx::ArrayRef<real> chargeB,
 102                                        gmx::ArrayRef<real> c6A,
 103                                        gmx::ArrayRef<real> c6B,
 104                                        gmx::ArrayRef<real> sigmaA,
 105                                        gmx::ArrayRef<real> sigmaB,
 106                                        const matrix        box,
 107                                        const rvec gmx_unused* x,
 108                                        real                   lambda_q,
 109                                        real                   lambda_lj,
 110                                        int                    maxshift_x,
 111                                        int                    maxshift_y,
 112                                        int64_t                step,
 113                                        bool                   useGpuPmePpComms,
 114                                        bool                   reinitGpuPmePpComms,
 115                                        bool                   sendCoordinatesFromGpu,
 116                                        GpuEventSynchronizer*  coordinatesReadyOnDeviceEvent)
 117 {
 118     gmx_domdec_t*         dd;
 119     gmx_pme_comm_n_box_t* cnb;
 120     int                   n;
 121
 122     dd = cr->dd;
 123     n  = dd_numHomeAtoms(*dd);
 124
 125     if (debug)
 126     {
 127         fprintf(debug,
 128                 "PP rank %d sending to PME rank %d: %d%s%s%s%s\n",
 129                 cr->sim_nodeid,
 130                 dd->pme_nodeid,
 131                 n,
 132                 (flags & PP_PME_CHARGE) ? " charges" : "",
 133                 (flags & PP_PME_SQRTC6) ? " sqrtC6" : "",
 134                 (flags & PP_PME_SIGMA) ? " sigma" : "",
 135                 (flags & PP_PME_COORD) ? " coordinates" : "");
 136     }
 137
 138     if (useGpuPmePpComms)
 139     {
 140         flags |= PP_PME_GPUCOMMS;
 141     }
 142
 143     if (c_useDelayedWait)
 144     {
 145         /* We can not use cnb until pending communication has finished */
 146         gmx_pme_send_coeffs_coords_wait(dd);
 147     }
 148
 149     if (dd->pme_receive_vir_ener)
 150     {
 151         /* Peer PP node: communicate all data */
 152         if (dd->cnb == nullptr)
 153         {
 154             snew(dd->cnb, 1);
 155         }
 156         cnb = dd->cnb;
 157
 158         cnb->flags      = flags;
 159         cnb->natoms     = n;
 160         cnb->maxshift_x = maxshift_x;
 161         cnb->maxshift_y = maxshift_y;
 162         cnb->lambda_q   = lambda_q;
 163         cnb->lambda_lj  = lambda_lj;
 164         cnb->step       = step;
 165         if (flags & PP_PME_COORD)
 166         {
 167             copy_mat(box, cnb->box);
 168         }
 169 #if GMX_MPI
 170         MPI_Isend(cnb,
 171                   sizeof(*cnb),
 172                   MPI_BYTE,
 173                   dd->pme_nodeid,
 174                   eCommType_CNB,
 175                   cr->mpi_comm_mysim,
 176                   &dd->req_pme[dd->nreq_pme++]);
 177 #endif
 178     }
 179     else if (flags & (PP_PME_CHARGE | PP_PME_SQRTC6 | PP_PME_SIGMA))
 180     {
 181 #if GMX_MPI
 182         /* Communicate only the number of atoms */
 183         MPI_Isend(&n,
 184                   sizeof(n),
 185                   MPI_BYTE,
 186                   dd->pme_nodeid,
 187                   eCommType_CNB,
 188                   cr->mpi_comm_mysim,
 189                   &dd->req_pme[dd->nreq_pme++]);
 190 #endif
 191     }
 192
 193 #if GMX_MPI
 194     if (n > 0)
 195     {
 196         if (flags & PP_PME_CHARGE)
 197         {
 198             MPI_Isend(chargeA.data(),
 199                       n * sizeof(real),
 200                       MPI_BYTE,
 201                       dd->pme_nodeid,
 202                       eCommType_ChargeA,
 203                       cr->mpi_comm_mysim,
 204                       &dd->req_pme[dd->nreq_pme++]);
 205         }
 206         if (flags & PP_PME_CHARGEB)
 207         {
 208             MPI_Isend(chargeB.data(),
 209                       n * sizeof(real),
 210                       MPI_BYTE,
 211                       dd->pme_nodeid,
 212                       eCommType_ChargeB,
 213                       cr->mpi_comm_mysim,
 214                       &dd->req_pme[dd->nreq_pme++]);
 215         }
 216         if (flags & PP_PME_SQRTC6)
 217         {
 218             MPI_Isend(c6A.data(),
 219                       n * sizeof(real),
 220                       MPI_BYTE,
 221                       dd->pme_nodeid,
 222                       eCommType_SQRTC6A,
 223                       cr->mpi_comm_mysim,
 224                       &dd->req_pme[dd->nreq_pme++]);
 225         }
 226         if (flags & PP_PME_SQRTC6B)
 227         {
 228             MPI_Isend(c6B.data(),
 229                       n * sizeof(real),
 230                       MPI_BYTE,
 231                       dd->pme_nodeid,
 232                       eCommType_SQRTC6B,
 233                       cr->mpi_comm_mysim,
 234                       &dd->req_pme[dd->nreq_pme++]);
 235         }
 236         if (flags & PP_PME_SIGMA)
 237         {
 238             MPI_Isend(sigmaA.data(),
 239                       n * sizeof(real),
 240                       MPI_BYTE,
 241                       dd->pme_nodeid,
 242                       eCommType_SigmaA,
 243                       cr->mpi_comm_mysim,
 244                       &dd->req_pme[dd->nreq_pme++]);
 245         }
 246         if (flags & PP_PME_SIGMAB)
 247         {
 248             MPI_Isend(sigmaB.data(),
 249                       n * sizeof(real),
 250                       MPI_BYTE,
 251                       dd->pme_nodeid,
 252                       eCommType_SigmaB,
 253                       cr->mpi_comm_mysim,
 254                       &dd->req_pme[dd->nreq_pme++]);
 255         }
 256         if (flags & PP_PME_COORD)
 257         {
 258             if (reinitGpuPmePpComms)
 259             {
 260                 fr->pmePpCommGpu->reinit(n);
 261             }
 262
 263
 264             /* MPI_Isend does not accept a const buffer pointer */
 265             real* xRealPtr = const_cast<real*>(x[0]);
 266             if (useGpuPmePpComms && (fr != nullptr))
 267             {
 268                 void* sendPtr = sendCoordinatesFromGpu
 269                                         ? static_cast<void*>(fr->stateGpu->getCoordinates())
 270                                         : static_cast<void*>(xRealPtr);
 271                 fr->pmePpCommGpu->sendCoordinatesToPmeCudaDirect(
 272                         sendPtr, n, sendCoordinatesFromGpu, coordinatesReadyOnDeviceEvent);
 273             }
 274             else
 275             {
 276                 MPI_Isend(xRealPtr,
 277                           n * sizeof(rvec),
 278                           MPI_BYTE,
 279                           dd->pme_nodeid,
 280                           eCommType_COORD,
 281                           cr->mpi_comm_mysim,
 282                           &dd->req_pme[dd->nreq_pme++]);
 283             }
 284         }
 285     }
 286 #else
 287     GMX_UNUSED_VALUE(fr);
 288     GMX_UNUSED_VALUE(chargeA);
 289     GMX_UNUSED_VALUE(chargeB);
 290     GMX_UNUSED_VALUE(c6A);
 291     GMX_UNUSED_VALUE(c6B);
 292     GMX_UNUSED_VALUE(sigmaA);
 293     GMX_UNUSED_VALUE(sigmaB);
 294     GMX_UNUSED_VALUE(reinitGpuPmePpComms);
 295     GMX_UNUSED_VALUE(sendCoordinatesFromGpu);
 296     GMX_UNUSED_VALUE(coordinatesReadyOnDeviceEvent);
 297 #endif
 298     if (!c_useDelayedWait)
 299     {
 300         /* Wait for the data to arrive */
 301         /* We can skip this wait as we are sure x and q will not be modified
 302          * before the next call to gmx_pme_send_x_q or gmx_pme_receive_f.
 303          */
 304         gmx_pme_send_coeffs_coords_wait(dd);
 305     }
 306 }
 307
 308 void gmx_pme_send_parameters(const t_commrec*           cr,
 309                              const interaction_const_t& interactionConst,
 310                              bool                       bFreeEnergy_q,
 311                              bool                       bFreeEnergy_lj,
 312                              gmx::ArrayRef<real>        chargeA,
 313                              gmx::ArrayRef<real>        chargeB,
 314                              gmx::ArrayRef<real>        sqrt_c6A,
 315                              gmx::ArrayRef<real>        sqrt_c6B,
 316                              gmx::ArrayRef<real>        sigmaA,
 317                              gmx::ArrayRef<real>        sigmaB,
 318                              int                        maxshift_x,
 319                              int                        maxshift_y)
 320 {
 321     unsigned int flags = 0;
 322
 323     if (EEL_PME(interactionConst.eeltype))
 324     {
 325         flags |= PP_PME_CHARGE;
 326     }
 327     if (EVDW_PME(interactionConst.vdwtype))
 328     {
 329         flags |= (PP_PME_SQRTC6 | PP_PME_SIGMA);
 330     }
 331     if (bFreeEnergy_q || bFreeEnergy_lj)
 332     {
 333         /* Assumes that the B state flags are in the bits just above
 334          * the ones for the A state. */
 335         flags |= (flags << 1);
 336     }
 337
 338     gmx_pme_send_coeffs_coords(nullptr,
 339                                cr,
 340                                flags,
 341                                chargeA,
 342                                chargeB,
 343                                sqrt_c6A,
 344                                sqrt_c6B,
 345                                sigmaA,
 346                                sigmaB,
 347                                nullptr,
 348                                nullptr,
 349                                0,
 350                                0,
 351                                maxshift_x,
 352                                maxshift_y,
 353                                -1,
 354                                false,
 355                                false,
 356                                false,
 357                                nullptr);
 358 }
 359
 360 void gmx_pme_send_coordinates(t_forcerec*           fr,
 361                               const t_commrec*      cr,
 362                               const matrix          box,
 363                               const rvec*           x,
 364                               real                  lambda_q,
 365                               real                  lambda_lj,
 366                               bool                  computeEnergyAndVirial,
 367                               int64_t               step,
 368                               bool                  useGpuPmePpComms,
 369                               bool                  receiveCoordinateAddressFromPme,
 370                               bool                  sendCoordinatesFromGpu,
 371                               GpuEventSynchronizer* coordinatesReadyOnDeviceEvent,
 372                               gmx_wallcycle*        wcycle)
 373 {
 374     wallcycle_start(wcycle, ewcPP_PMESENDX);
 375
 376     unsigned int flags = PP_PME_COORD;
 377     if (computeEnergyAndVirial)
 378     {
 379         flags |= PP_PME_ENER_VIR;
 380     }
 381     gmx_pme_send_coeffs_coords(fr,
 382                                cr,
 383                                flags,
 384                                {},
 385                                {},
 386                                {},
 387                                {},
 388                                {},
 389                                {},
 390                                box,
 391                                x,
 392                                lambda_q,
 393                                lambda_lj,
 394                                0,
 395                                0,
 396                                step,
 397                                useGpuPmePpComms,
 398                                receiveCoordinateAddressFromPme,
 399                                sendCoordinatesFromGpu,
 400                                coordinatesReadyOnDeviceEvent);
 401
 402     wallcycle_stop(wcycle, ewcPP_PMESENDX);
 403 }
 404
 405 void gmx_pme_send_finish(const t_commrec* cr)
 406 {
 407     unsigned int flags = PP_PME_FINISH;
 408
 409     gmx_pme_send_coeffs_coords(
 410             nullptr, cr, flags, {}, {}, {}, {}, {}, {}, nullptr, nullptr, 0, 0, 0, 0, -1, false, false, false, nullptr);
 411 }
 412
 413 void gmx_pme_send_switchgrid(const t_commrec* cr, ivec grid_size, real ewaldcoeff_q, real ewaldcoeff_lj)
 414 {
 415 #if GMX_MPI
 416     gmx_pme_comm_n_box_t cnb;
 417
 418     /* Only let one PP node signal each PME node */
 419     if (cr->dd->pme_receive_vir_ener)
 420     {
 421         cnb.flags = PP_PME_SWITCHGRID;
 422         copy_ivec(grid_size, cnb.grid_size);
 423         cnb.ewaldcoeff_q  = ewaldcoeff_q;
 424         cnb.ewaldcoeff_lj = ewaldcoeff_lj;
 425
 426         /* We send this, uncommon, message blocking to simplify the code */
 427         MPI_Send(&cnb, sizeof(cnb), MPI_BYTE, cr->dd->pme_nodeid, eCommType_CNB, cr->mpi_comm_mysim);
 428     }
 429 #else
 430     GMX_UNUSED_VALUE(cr);
 431     GMX_UNUSED_VALUE(grid_size);
 432     GMX_UNUSED_VALUE(ewaldcoeff_q);
 433     GMX_UNUSED_VALUE(ewaldcoeff_lj);
 434 #endif
 435 }
 436
 437 void gmx_pme_send_resetcounters(const t_commrec gmx_unused* cr, int64_t gmx_unused step)
 438 {
 439 #if GMX_MPI
 440     gmx_pme_comm_n_box_t cnb;
 441
 442     /* Only let one PP node signal each PME node */
 443     if (cr->dd->pme_receive_vir_ener)
 444     {
 445         cnb.flags = PP_PME_RESETCOUNTERS;
 446         cnb.step  = step;
 447
 448         /* We send this, uncommon, message blocking to simplify the code */
 449         MPI_Send(&cnb, sizeof(cnb), MPI_BYTE, cr->dd->pme_nodeid, eCommType_CNB, cr->mpi_comm_mysim);
 450     }
 451 #endif
 452 }
 453
 454 /*! \brief Receive virial and energy from PME rank */
 455 static void receive_virial_energy(const t_commrec*      cr,
 456                                   gmx::ForceWithVirial* forceWithVirial,
 457                                   real*                 energy_q,
 458                                   real*                 energy_lj,
 459                                   real*                 dvdlambda_q,
 460                                   real*                 dvdlambda_lj,
 461                                   float*                pme_cycles)
 462 {
 463     gmx_pme_comm_vir_ene_t cve;
 464
 465     if (cr->dd->pme_receive_vir_ener)
 466     {
 467         if (debug)
 468         {
 469             fprintf(debug,
 470                     "PP rank %d receiving from PME rank %d: virial and energy\n",
 471                     cr->sim_nodeid,
 472                     cr->dd->pme_nodeid);
 473         }
 474 #if GMX_MPI
 475         MPI_Recv(&cve, sizeof(cve), MPI_BYTE, cr->dd->pme_nodeid, 1, cr->mpi_comm_mysim, MPI_STATUS_IGNORE);
 476 #else
 477         memset(&cve, 0, sizeof(cve));
 478 #endif
 479
 480         forceWithVirial->addVirialContribution(cve.vir_q);
 481         forceWithVirial->addVirialContribution(cve.vir_lj);
 482         *energy_q  = cve.energy_q;
 483         *energy_lj = cve.energy_lj;
 484         *dvdlambda_q += cve.dvdlambda_q;
 485         *dvdlambda_lj += cve.dvdlambda_lj;
 486         *pme_cycles = cve.cycles;
 487
 488         if (cve.stop_cond != gmx_stop_cond_none)
 489         {
 490             gmx_set_stop_condition(cve.stop_cond);
 491         }
 492     }
 493     else
 494     {
 495         *energy_q   = 0;
 496         *energy_lj  = 0;
 497         *pme_cycles = 0;
 498     }
 499 }
 500
 501 /*! \brief Recieve force data from PME ranks */
 502 static void recvFFromPme(gmx::PmePpCommGpu* pmePpCommGpu,
 503                          void*              recvptr,
 504                          int                n,
 505                          const t_commrec*   cr,
 506                          bool               useGpuPmePpComms,
 507                          bool               receivePmeForceToGpu)
 508 {
 509     if (useGpuPmePpComms)
 510     {
 511         GMX_ASSERT(pmePpCommGpu != nullptr, "Need valid pmePpCommGpu");
 512         // Receive directly using CUDA memory copy
 513         pmePpCommGpu->receiveForceFromPmeCudaDirect(recvptr, n, receivePmeForceToGpu);
 514     }
 515     else
 516     {
 517         // Receive data using MPI
 518 #if GMX_MPI
 519         MPI_Recv(recvptr, n * sizeof(rvec), MPI_BYTE, cr->dd->pme_nodeid, 0, cr->mpi_comm_mysim, MPI_STATUS_IGNORE);
 520 #else
 521         GMX_UNUSED_VALUE(cr);
 522 #endif
 523     }
 524 }
 525
 526
 527 void gmx_pme_receive_f(gmx::PmePpCommGpu*    pmePpCommGpu,
 528                        const t_commrec*      cr,
 529                        gmx::ForceWithVirial* forceWithVirial,
 530                        real*                 energy_q,
 531                        real*                 energy_lj,
 532                        real*                 dvdlambda_q,
 533                        real*                 dvdlambda_lj,
 534                        bool                  useGpuPmePpComms,
 535                        bool                  receivePmeForceToGpu,
 536                        float*                pme_cycles)
 537 {
 538     if (c_useDelayedWait)
 539     {
 540         /* Wait for the x request to finish */
 541         gmx_pme_send_coeffs_coords_wait(cr->dd);
 542     }
 543
 544     const int               natoms = dd_numHomeAtoms(*cr->dd);
 545     std::vector<gmx::RVec>& buffer = cr->dd->pmeForceReceiveBuffer;
 546     buffer.resize(natoms);
 547
 548     void* recvptr = reinterpret_cast<void*>(buffer.data());
 549     recvFFromPme(pmePpCommGpu, recvptr, natoms, cr, useGpuPmePpComms, receivePmeForceToGpu);
 550
 551     int nt = gmx_omp_nthreads_get_simple_rvec_task(emntDefault, natoms);
 552
 553     gmx::ArrayRef<gmx::RVec> f = forceWithVirial->force_;
 554
 555     if (!receivePmeForceToGpu)
 556     {
 557         /* Note that we would like to avoid this conditional by putting it
 558          * into the omp pragma instead, but then we still take the full
 559          * omp parallel for overhead (at least with gcc5).
 560          */
 561         if (nt == 1)
 562         {
 563             for (int i = 0; i < natoms; i++)
 564             {
 565                 f[i] += buffer[i];
 566             }
 567         }
 568         else
 569         {
 570 #pragma omp parallel for num_threads(nt) schedule(static)
 571             for (int i = 0; i < natoms; i++)
 572             {
 573                 f[i] += buffer[i];
 574             }
 575         }
 576     }
 577
 578     receive_virial_energy(cr, forceWithVirial, energy_q, energy_lj, dvdlambda_q, dvdlambda_lj, pme_cycles);
 579 }