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37 /*! \libinternal \file
39 * \brief This file contains function declarations necessary for
40 * computing energies and forces for the PME long-ranged part (Coulomb
43 * \author Berk Hess <hess@kth.se>
45 * \ingroup module_ewald
48 #ifndef GMX_EWALD_PME_H
49 #define GMX_EWALD_PME_H
53 #include "gromacs/gpu_utils/gpu_macros.h"
54 #include "gromacs/math/vectypes.h"
55 #include "gromacs/timing/walltime_accounting.h"
56 #include "gromacs/utility/arrayref.h"
57 #include "gromacs/utility/basedefinitions.h"
58 #include "gromacs/utility/real.h"
61 struct interaction_const_t;
66 struct gmx_wallclock_gpu_pme_t;
67 struct gmx_device_info_t;
73 enum class GpuTaskCompletion;
76 using PmeGpuProgramHandle = const PmeGpuProgram *;
80 class ForceWithVirial;
82 enum class PinningPolicy : int;
86 GMX_SUM_GRID_FORWARD, GMX_SUM_GRID_BACKWARD
89 /*! \brief Possible PME codepaths on a rank.
90 * \todo: make this enum class with gmx_pme_t C++ refactoring
94 None, //!< No PME task is done
95 CPU, //!< Whole PME computation is done on CPU
96 GPU, //!< Whole PME computation is done on GPU
97 Mixed, //!< Mixed mode: only spread and gather run on GPU; FFT and solving are done on CPU.
100 //! PME gathering output forces treatment
101 enum class PmeForceOutputHandling
103 Set, /**< Gather simply writes into provided force buffer */
104 ReduceWithInput, /**< Gather adds its output to the buffer.
105 On GPU, that means additional H2D copy before the kernel launch. */
108 /*! \brief Return the smallest allowed PME grid size for \p pmeOrder */
109 int minimalPmeGridSize(int pmeOrder);
111 /*! \brief Check restrictions on pme_order and the PME grid nkx,nky,nkz.
113 * With errorsAreFatal=true, an exception or fatal error is generated
114 * on violation of restrictions.
115 * With errorsAreFatal=false, false is returned on violation of restrictions.
116 * When all restrictions are obeyed, true is returned.
117 * Argument useThreads tells if any MPI rank doing PME uses more than 1 threads.
118 * If at calling useThreads is unknown, pass true for conservative checking.
120 * The PME GPU restrictions are checked separately during pme_gpu_init().
122 bool gmx_pme_check_restrictions(int pme_order,
123 int nkx, int nky, int nkz,
124 int numPmeDomainsAlongX,
126 bool errorsAreFatal);
128 /*! \brief Construct PME data
130 * \throws gmx::InconsistentInputError if input grid sizes/PME order are inconsistent.
131 * \returns Pointer to newly allocated and initialized PME data.
133 * \todo We should evolve something like a \c GpuManager that holds \c
134 * gmx_device_info_t * and \c PmeGpuProgramHandle and perhaps other
135 * related things whose lifetime can/should exceed that of a task (or
136 * perhaps task manager). See Redmine #2522.
138 gmx_pme_t *gmx_pme_init(const t_commrec *cr,
139 const NumPmeDomains &numPmeDomains,
140 const t_inputrec *ir, int homenr,
141 gmx_bool bFreeEnergy_q, gmx_bool bFreeEnergy_lj,
142 gmx_bool bReproducible,
143 real ewaldcoeff_q, real ewaldcoeff_lj,
147 const gmx_device_info_t *gpuInfo,
148 PmeGpuProgramHandle pmeGpuProgram,
149 const gmx::MDLogger &mdlog);
151 /*! \brief Destroys the PME data structure.*/
152 void gmx_pme_destroy(gmx_pme_t *pme);
155 /*! \brief Flag values that control what gmx_pme_do() will calculate
157 * These can be combined with bitwise-OR if more than one thing is required.
159 #define GMX_PME_SPREAD (1<<0)
160 #define GMX_PME_SOLVE (1<<1)
161 #define GMX_PME_CALC_F (1<<2)
162 #define GMX_PME_CALC_ENER_VIR (1<<3)
163 /* This forces the grid to be backtransformed even without GMX_PME_CALC_F */
164 #define GMX_PME_CALC_POT (1<<4)
166 #define GMX_PME_DO_ALL_F (GMX_PME_SPREAD | GMX_PME_SOLVE | GMX_PME_CALC_F)
169 /*! \brief Do a PME calculation on a CPU for the long range electrostatics and/or LJ.
171 * The meaning of \p flags is defined above, and determines which
172 * parts of the calculation are performed.
174 * \return 0 indicates all well, non zero is an error code.
176 int gmx_pme_do(struct gmx_pme_t *pme,
177 int start, int homenr,
179 real chargeA[], real chargeB[],
180 real c6A[], real c6B[],
181 real sigmaA[], real sigmaB[],
182 matrix box, const t_commrec *cr,
183 int maxshift_x, int maxshift_y,
184 t_nrnb *nrnb, gmx_wallcycle *wcycle,
185 matrix vir_q, matrix vir_lj,
186 real *energy_q, real *energy_lj,
187 real lambda_q, real lambda_lj,
188 real *dvdlambda_q, real *dvdlambda_lj,
191 /*! \brief Called on the nodes that do PME exclusively */
192 int gmx_pmeonly(struct gmx_pme_t *pme,
193 const t_commrec *cr, t_nrnb *mynrnb,
194 gmx_wallcycle *wcycle,
195 gmx_walltime_accounting_t walltime_accounting,
196 t_inputrec *ir, PmeRunMode runMode);
198 /*! \brief Calculate the PME grid energy V for n charges.
200 * The potential (found in \p pme) must have been found already with a
201 * call to gmx_pme_do() with at least GMX_PME_SPREAD and GMX_PME_SOLVE
202 * specified. Note that the charges are not spread on the grid in the
203 * pme struct. Currently does not work in parallel or with free
206 void gmx_pme_calc_energy(struct gmx_pme_t *pme, int n, rvec *x, real *q, real *V);
208 /*! \brief Send the charges and maxshift to out PME-only node. */
209 void gmx_pme_send_parameters(const t_commrec *cr,
210 const interaction_const_t *ic,
211 gmx_bool bFreeEnergy_q, gmx_bool bFreeEnergy_lj,
212 real *chargeA, real *chargeB,
213 real *sqrt_c6A, real *sqrt_c6B,
214 real *sigmaA, real *sigmaB,
215 int maxshift_x, int maxshift_y);
217 /*! \brief Send the coordinates to our PME-only node and request a PME calculation */
218 void gmx_pme_send_coordinates(const t_commrec *cr, matrix box, rvec *x,
219 real lambda_q, real lambda_lj,
221 int64_t step, gmx_wallcycle *wcycle);
223 /*! \brief Tell our PME-only node to finish */
224 void gmx_pme_send_finish(const t_commrec *cr);
226 /*! \brief Tell our PME-only node to reset all cycle and flop counters */
227 void gmx_pme_send_resetcounters(const t_commrec *cr, int64_t step);
229 /*! \brief PP nodes receive the long range forces from the PME nodes */
230 void gmx_pme_receive_f(const t_commrec *cr,
231 gmx::ForceWithVirial *forceWithVirial,
232 real *energy_q, real *energy_lj,
233 real *dvdlambda_q, real *dvdlambda_lj,
237 * This function updates the local atom data on GPU after DD (charges, coordinates, etc.).
238 * TODO: it should update the PME CPU atom data as well.
239 * (currently PME CPU call gmx_pme_do() gets passed the input pointers for each computation).
241 * \param[in] pme The PME structure.
242 * \param[in] nAtoms The number of particles.
243 * \param[in] charges The pointer to the array of particle charges.
245 void gmx_pme_reinit_atoms(const gmx_pme_t *pme, int nAtoms, const real *charges);
247 /* A block of PME GPU functions */
249 /*! \brief Checks whether the GROMACS build allows to run PME on GPU.
250 * TODO: this partly duplicates an internal PME assert function
251 * pme_gpu_check_restrictions(), except that works with a
252 * formed gmx_pme_t structure. Should that one go away/work with inputrec?
254 * \param[in] hwinfo Information about the detected hardware
255 * \param[out] error If non-null, the error message when PME is not supported on GPU.
257 * \returns true if PME can run on GPU on this build, false otherwise.
259 bool pme_gpu_supports_build(const gmx_hw_info_t &hwinfo,
262 /*! \brief Checks whether the input system allows to run PME on GPU.
263 * TODO: this partly duplicates an internal PME assert function
264 * pme_gpu_check_restrictions(), except that works with a
265 * formed gmx_pme_t structure. Should that one go away/work with inputrec?
267 * \param[in] ir Input system.
268 * \param[in] mtop Complete system topology to check if an FE simulation perturbs charges.
269 * \param[out] error If non-null, the error message if the input is not supported on GPU.
271 * \returns true if PME can run on GPU with this input, false otherwise.
273 bool pme_gpu_supports_input(const t_inputrec &ir, const gmx_mtop_t &mtop, std::string *error);
276 * Returns the active PME codepath (CPU, GPU, mixed).
277 * \todo This is a rather static data that should be managed by the higher level task scheduler.
279 * \param[in] pme The PME data structure.
280 * \returns active PME codepath.
282 PmeRunMode pme_run_mode(const gmx_pme_t *pme);
284 /*! \libinternal \brief
285 * Return the pinning policy appropriate for this build configuration
286 * for relevant buffers used for PME task on this rank (e.g. running
288 gmx::PinningPolicy pme_get_pinning_policy();
291 * Tells if PME is enabled to run on GPU (not necessarily active at the moment).
292 * \todo This is a rather static data that should be managed by the hardware assignment manager.
293 * For now, it is synonymous with the active PME codepath (in the absence of dynamic switching).
295 * \param[in] pme The PME data structure.
296 * \returns true if PME can run on GPU, false otherwise.
298 inline bool pme_gpu_task_enabled(const gmx_pme_t *pme)
300 return (pme != nullptr) && (pme_run_mode(pme) != PmeRunMode::CPU);
303 // The following functions are all the PME GPU entry points,
304 // currently inlining to nothing on non-CUDA builds.
307 * Resets the PME GPU timings. To be called at the reset step.
309 * \param[in] pme The PME structure.
311 GPU_FUNC_QUALIFIER void pme_gpu_reset_timings(const gmx_pme_t *GPU_FUNC_ARGUMENT(pme)) GPU_FUNC_TERM
314 * Copies the PME GPU timings to the gmx_wallclock_gpu_pme_t structure (for log output). To be called at the run end.
316 * \param[in] pme The PME structure.
317 * \param[in] timings The gmx_wallclock_gpu_pme_t structure.
319 GPU_FUNC_QUALIFIER void pme_gpu_get_timings(const gmx_pme_t *GPU_FUNC_ARGUMENT(pme),
320 gmx_wallclock_gpu_pme_t *GPU_FUNC_ARGUMENT(timings)) GPU_FUNC_TERM
322 /* The main PME GPU functions */
325 * Prepares PME on GPU computation (updating the box if needed)
326 * \param[in] pme The PME data structure.
327 * \param[in] needToUpdateBox Tells if the stored unit cell parameters should be updated from \p box.
328 * \param[in] box The unit cell box.
329 * \param[in] wcycle The wallclock counter.
330 * \param[in] flags The combination of flags to affect this PME computation.
331 * The flags are the GMX_PME_ flags from pme.h.
333 GPU_FUNC_QUALIFIER void pme_gpu_prepare_computation(gmx_pme_t *GPU_FUNC_ARGUMENT(pme),
334 bool GPU_FUNC_ARGUMENT(needToUpdateBox),
335 const matrix GPU_FUNC_ARGUMENT(box),
336 gmx_wallcycle *GPU_FUNC_ARGUMENT(wcycle),
337 int GPU_FUNC_ARGUMENT(flags)) GPU_FUNC_TERM
340 * Launches first stage of PME on GPU - H2D input transfers, spreading kernel, and D2H grid transfer if needed.
342 * \param[in] pme The PME data structure.
343 * \param[in] x The array of local atoms' coordinates.
344 * \param[in] wcycle The wallclock counter.
346 GPU_FUNC_QUALIFIER void pme_gpu_launch_spread(gmx_pme_t *GPU_FUNC_ARGUMENT(pme),
347 const rvec *GPU_FUNC_ARGUMENT(x),
348 gmx_wallcycle *GPU_FUNC_ARGUMENT(wcycle)) GPU_FUNC_TERM
351 * Launches middle stages of PME (FFT R2C, solving, FFT C2R) either on GPU or on CPU, depending on the run mode.
353 * \param[in] pme The PME data structure.
354 * \param[in] wcycle The wallclock counter.
356 GPU_FUNC_QUALIFIER void pme_gpu_launch_complex_transforms(gmx_pme_t *GPU_FUNC_ARGUMENT(pme),
357 gmx_wallcycle *GPU_FUNC_ARGUMENT(wcycle)) GPU_FUNC_TERM
360 * Launches last stage of PME on GPU - force gathering and D2H force transfer.
362 * \param[in] pme The PME data structure.
363 * \param[in] wcycle The wallclock counter.
364 * \param[in] forceTreatment Tells how data should be treated. The gathering kernel either stores
365 * the output reciprocal forces into the host array, or copies its contents to the GPU first
366 * and accumulates. The reduction is non-atomic.
368 GPU_FUNC_QUALIFIER void pme_gpu_launch_gather(const gmx_pme_t *GPU_FUNC_ARGUMENT(pme),
369 gmx_wallcycle *GPU_FUNC_ARGUMENT(wcycle),
370 PmeForceOutputHandling GPU_FUNC_ARGUMENT(forceTreatment)) GPU_FUNC_TERM
373 * Blocks until PME GPU tasks are completed, and gets the output forces and virial/energy
374 * (if they were to be computed).
376 * \param[in] pme The PME data structure.
377 * \param[out] wcycle The wallclock counter.
378 * \param[out] forces The output forces.
379 * \param[out] virial The output virial matrix.
380 * \param[out] energy The output energy.
382 GPU_FUNC_QUALIFIER void pme_gpu_wait_finish_task(const gmx_pme_t *GPU_FUNC_ARGUMENT(pme),
383 gmx_wallcycle *GPU_FUNC_ARGUMENT(wcycle),
384 gmx::ArrayRef<const gmx::RVec> *GPU_FUNC_ARGUMENT(forces),
385 matrix GPU_FUNC_ARGUMENT(virial),
386 real *GPU_FUNC_ARGUMENT(energy)) GPU_FUNC_TERM
388 * Attempts to complete PME GPU tasks.
390 * The \p completionKind argument controls whether the function blocks until all
391 * PME GPU tasks enqueued completed (as pme_gpu_wait_finish_task() does) or only
392 * checks and returns immediately if they did not.
393 * When blocking or the tasks have completed it also gets the output forces
394 * by assigning the ArrayRef to the \p forces pointer passed in.
395 * Virial/energy are also outputs if they were to be computed.
397 * Note: also launches the reinitalization of the PME output buffers.
398 * TODO: this should be moved out to avoid miscounting its wall-time (as wait iso launch).
400 * \param[in] pme The PME data structure.
401 * \param[in] wcycle The wallclock counter.
402 * \param[out] forces The output forces.
403 * \param[out] virial The output virial matrix.
404 * \param[out] energy The output energy.
405 * \param[in] completionKind Indicates whether PME task completion should only be checked rather than waited for
406 * \returns True if the PME GPU tasks have completed
408 GPU_FUNC_QUALIFIER bool pme_gpu_try_finish_task(const gmx_pme_t *GPU_FUNC_ARGUMENT(pme),
409 gmx_wallcycle *GPU_FUNC_ARGUMENT(wcycle),
410 gmx::ArrayRef<const gmx::RVec> *GPU_FUNC_ARGUMENT(forces),
411 matrix GPU_FUNC_ARGUMENT(virial),
412 real *GPU_FUNC_ARGUMENT(energy),
413 GpuTaskCompletion GPU_FUNC_ARGUMENT(completionKind)) GPU_FUNC_TERM_WITH_RETURN(false)
416 * The PME GPU reinitialization function that is called both at the end of any PME computation and on any load balancing.
418 * Clears the internal grid and energy/virial buffers; it is not safe to start
419 * the PME computation without calling this.
420 * Note that unlike in the nbnxn module, the force buffer does not need clearing.
422 * \todo Rename this function to *clear* -- it clearly only does output resetting
423 * and we should be clear about what the function does..
425 * \param[in] pme The PME data structure.
426 * \param[in] wcycle The wallclock counter.
428 GPU_FUNC_QUALIFIER void pme_gpu_reinit_computation(const gmx_pme_t *GPU_FUNC_ARGUMENT(pme),
429 gmx_wallcycle *GPU_FUNC_ARGUMENT(wcycle)) GPU_FUNC_TERM