/*
* This file is part of the GROMACS molecular simulation package.
*
- * Copyright (c) 2019,2020, by the GROMACS development team, led by
+ * Copyright (c) 2019,2020,2021, by the GROMACS development team, led by
* Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
* and including many others, as listed in the AUTHORS file in the
* top-level source directory and at http://www.gromacs.org.
#include <assert.h>
#include <stdio.h>
+#include <utility>
+
#include "gromacs/domdec/domdec.h"
#include "gromacs/domdec/domdec_struct.h"
#include "gromacs/domdec/gpuhaloexchange.h"
#include "gromacs/gpu_utils/cudautils.cuh"
#include "gromacs/gpu_utils/device_context.h"
#include "gromacs/gpu_utils/devicebuffer.h"
-#include "gromacs/gpu_utils/gpueventsynchronizer.cuh"
+#include "gromacs/gpu_utils/gpueventsynchronizer.h"
#include "gromacs/gpu_utils/typecasts.cuh"
#include "gromacs/gpu_utils/vectype_ops.cuh"
#include "gromacs/math/vectypes.h"
*gm_dataDest = *gm_dataSrc;
}
}
-
- return;
}
/*! \brief unpack non-local force data buffer on the GPU using pre-populated "map" containing index
*gm_dataDest = *gm_dataSrc;
}
}
-
- return;
}
void GpuHaloExchange::Impl::reinitHalo(float3* d_coordinatesBuffer, float3* d_forcesBuffer)
{
- wallcycle_start(wcycle_, ewcDOMDEC);
- wallcycle_sub_start(wcycle_, ewcsDD_GPU);
+ wallcycle_start(wcycle_, WallCycleCounter::Domdec);
+ wallcycle_sub_start(wcycle_, WallCycleSubCounter::DDGpu);
d_x_ = d_coordinatesBuffer;
d_f_ = d_forcesBuffer;
xSendSize_ = newSize;
#if GMX_MPI
- MPI_Sendrecv(&xSendSize_, sizeof(int), MPI_BYTE, sendRankX_, 0, &xRecvSize_, sizeof(int),
- MPI_BYTE, recvRankX_, 0, mpi_comm_mysim_, MPI_STATUS_IGNORE);
+ MPI_Sendrecv(&xSendSize_,
+ sizeof(int),
+ MPI_BYTE,
+ sendRankX_,
+ 0,
+ &xRecvSize_,
+ sizeof(int),
+ MPI_BYTE,
+ recvRankX_,
+ 0,
+ mpi_comm_mysim_,
+ MPI_STATUS_IGNORE);
#endif
fSendSize_ = xRecvSize_;
fRecvSize_ = xSendSize_;
"halo exchange index mapping array");
std::copy(ind.index.begin(), ind.index.end(), h_indexMap_.begin());
- copyToDeviceBuffer(&d_indexMap_, h_indexMap_.data(), 0, newSize, nonLocalStream_,
- GpuApiCallBehavior::Async, nullptr);
+ copyToDeviceBuffer(
+ &d_indexMap_, h_indexMap_.data(), 0, newSize, *haloStream_, GpuApiCallBehavior::Async, nullptr);
}
- // This rank will push data to its neighbor, so needs to know
- // the remote receive address and similarly send its receive
- // address to other neighbour. We can do this here in reinit fn
- // since the pointers will not change until the next NS step.
- // Coordinates buffer:
- void* recvPtr = static_cast<void*>(&d_x_[atomOffset_]);
#if GMX_MPI
- MPI_Sendrecv(&recvPtr, sizeof(void*), MPI_BYTE, recvRankX_, 0, &remoteXPtr_, sizeof(void*),
- MPI_BYTE, sendRankX_, 0, mpi_comm_mysim_, MPI_STATUS_IGNORE);
-
- // Force buffer:
- recvPtr = static_cast<void*>(d_recvBuf_);
- MPI_Sendrecv(&recvPtr, sizeof(void*), MPI_BYTE, recvRankF_, 0, &remoteFPtr_, sizeof(void*),
- MPI_BYTE, sendRankF_, 0, mpi_comm_mysim_, MPI_STATUS_IGNORE);
+ // Exchange of remote addresses from neighboring ranks is needed only with CUDA-direct as cudamemcpy needs both src/dst pointer
+ // MPI calls such as MPI_send doesn't worry about receiving address, that is taken care by MPI_recv call in neighboring rank
+ if (GMX_THREAD_MPI)
+ {
+ // This rank will push data to its neighbor, so needs to know
+ // the remote receive address and similarly send its receive
+ // address to other neighbour. We can do this here in reinit fn
+ // since the pointers will not change until the next NS step.
+
+ // Coordinates buffer:
+ float3* recvPtr = &d_x_[atomOffset_];
+ MPI_Sendrecv(&recvPtr,
+ sizeof(void*),
+ MPI_BYTE,
+ recvRankX_,
+ 0,
+ &remoteXPtr_,
+ sizeof(void*),
+ MPI_BYTE,
+ sendRankX_,
+ 0,
+ mpi_comm_mysim_,
+ MPI_STATUS_IGNORE);
+
+ // Force buffer:
+ recvPtr = d_recvBuf_;
+ MPI_Sendrecv(&recvPtr,
+ sizeof(void*),
+ MPI_BYTE,
+ recvRankF_,
+ 0,
+ &remoteFPtr_,
+ sizeof(void*),
+ MPI_BYTE,
+ sendRankF_,
+ 0,
+ mpi_comm_mysim_,
+ MPI_STATUS_IGNORE);
+ }
#endif
- wallcycle_sub_stop(wcycle_, ewcsDD_GPU);
- wallcycle_stop(wcycle_, ewcDOMDEC);
+ wallcycle_sub_stop(wcycle_, WallCycleSubCounter::DDGpu);
+ wallcycle_stop(wcycle_, WallCycleCounter::Domdec);
+}
- return;
+void GpuHaloExchange::Impl::enqueueWaitRemoteCoordinatesReadyEvent(GpuEventSynchronizer* coordinatesReadyOnDeviceEvent)
+{
+ GMX_ASSERT(coordinatesReadyOnDeviceEvent != nullptr,
+ "Co-ordinate Halo exchange requires valid co-ordinate ready event");
+
+ // Wait for event from receiving task that remote coordinates are ready, and enqueue that event to stream used
+ // for subsequent data push. This avoids a race condition with the remote data being written in the previous timestep.
+ // Similarly send event to task that will push data to this task.
+ GpuEventSynchronizer* remoteCoordinatesReadyOnDeviceEvent;
+ MPI_Sendrecv(&coordinatesReadyOnDeviceEvent,
+ sizeof(GpuEventSynchronizer*), //NOLINT(bugprone-sizeof-expression)
+ MPI_BYTE,
+ recvRankX_,
+ 0,
+ &remoteCoordinatesReadyOnDeviceEvent,
+ sizeof(GpuEventSynchronizer*), //NOLINT(bugprone-sizeof-expression)
+ MPI_BYTE,
+ sendRankX_,
+ 0,
+ mpi_comm_mysim_,
+ MPI_STATUS_IGNORE);
+ remoteCoordinatesReadyOnDeviceEvent->enqueueWaitEvent(*haloStream_);
}
-void GpuHaloExchange::Impl::communicateHaloCoordinates(const matrix box,
- GpuEventSynchronizer* coordinatesReadyOnDeviceEvent)
+GpuEventSynchronizer* GpuHaloExchange::Impl::communicateHaloCoordinates(const matrix box,
+ GpuEventSynchronizer* dependencyEvent)
{
+ wallcycle_start(wcycle_, WallCycleCounter::LaunchGpu);
- wallcycle_start(wcycle_, ewcLAUNCH_GPU);
- if (pulse_ == 0)
- {
- // ensure stream waits until coordinate data is available on device
- coordinatesReadyOnDeviceEvent->enqueueWaitEvent(nonLocalStream_);
- }
+ // ensure stream waits until dependency has been satisfied
+ dependencyEvent->enqueueWaitEvent(*haloStream_);
- wallcycle_sub_start(wcycle_, ewcsLAUNCH_GPU_MOVEX);
+ wallcycle_sub_start(wcycle_, WallCycleSubCounter::LaunchGpuMoveX);
// launch kernel to pack send buffer
KernelLaunchConfig config;
// is used every step to pass the shift vector as an argument of
// the packing kernel.
const int boxDimensionIndex = dd_->dim[dimIndex_];
- const float3 coordinateShift{ box[boxDimensionIndex][XX], box[boxDimensionIndex][YY],
+ const float3 coordinateShift{ box[boxDimensionIndex][XX],
+ box[boxDimensionIndex][YY],
box[boxDimensionIndex][ZZ] };
// Avoid launching kernel when there is no work to do
{
auto kernelFn = usePBC_ ? packSendBufKernel<true> : packSendBufKernel<false>;
- const auto kernelArgs = prepareGpuKernelArguments(kernelFn, config, &sendBuf, &d_x,
- &indexMap, &size, &coordinateShift);
+ const auto kernelArgs = prepareGpuKernelArguments(
+ kernelFn, config, &sendBuf, &d_x, &indexMap, &size, &coordinateShift);
- launchGpuKernel(kernelFn, config, nonLocalStream_, nullptr,
- "Domdec GPU Apply X Halo Exchange", kernelArgs);
+ launchGpuKernel(kernelFn, config, *haloStream_, nullptr, "Domdec GPU Apply X Halo Exchange", kernelArgs);
}
- wallcycle_sub_stop(wcycle_, ewcsLAUNCH_GPU_MOVEX);
- wallcycle_stop(wcycle_, ewcLAUNCH_GPU);
+ wallcycle_sub_stop(wcycle_, WallCycleSubCounter::LaunchGpuMoveX);
+ wallcycle_stop(wcycle_, WallCycleCounter::LaunchGpu);
// Consider time spent in communicateHaloData as Comm.X counter
// ToDo: We need further refinement here as communicateHaloData includes launch time for cudamemcpyasync
- wallcycle_start(wcycle_, ewcMOVEX);
+ wallcycle_start(wcycle_, WallCycleCounter::MoveX);
+
+ // wait for remote co-ordinates is implicit with process-MPI as non-local stream is synchronized before MPI calls
+ // and MPI_Waitall call makes sure both neighboring ranks' non-local stream is synchronized before data transfer is initiated
+ if (GMX_THREAD_MPI && dimIndex_ == 0 && pulse_ == 0)
+ {
+ enqueueWaitRemoteCoordinatesReadyEvent(dependencyEvent);
+ }
+
+ float3* recvPtr = GMX_THREAD_MPI ? remoteXPtr_ : &d_x_[atomOffset_];
+ communicateHaloData(d_sendBuf_, xSendSize_, sendRankX_, recvPtr, xRecvSize_, recvRankX_);
- communicateHaloData(d_x_, HaloQuantity::HaloCoordinates, coordinatesReadyOnDeviceEvent);
+ coordinateHaloLaunched_.markEvent(*haloStream_);
- wallcycle_stop(wcycle_, ewcMOVEX);
+ wallcycle_stop(wcycle_, WallCycleCounter::MoveX);
- return;
+ return &coordinateHaloLaunched_;
}
// The following method should be called after non-local buffer operations,
-// and before the local buffer operations. It operates in the non-local stream.
-void GpuHaloExchange::Impl::communicateHaloForces(bool accumulateForces)
+// and before the local buffer operations.
+void GpuHaloExchange::Impl::communicateHaloForces(bool accumulateForces,
+ FixedCapacityVector<GpuEventSynchronizer*, 2>* dependencyEvents)
{
+
// Consider time spent in communicateHaloData as Comm.F counter
// ToDo: We need further refinement here as communicateHaloData includes launch time for cudamemcpyasync
- wallcycle_start(wcycle_, ewcMOVEF);
+ wallcycle_start(wcycle_, WallCycleCounter::MoveF);
- // Communicate halo data (in non-local stream)
- communicateHaloData(d_f_, HaloQuantity::HaloForces, nullptr);
+ while (!dependencyEvents->empty())
+ {
+ auto* dependency = dependencyEvents->back();
+ dependency->enqueueWaitEvent(*haloStream_);
+ dependencyEvents->pop_back();
+ }
- wallcycle_stop(wcycle_, ewcMOVEF);
+ float3* recvPtr = GMX_THREAD_MPI ? remoteFPtr_ : d_recvBuf_;
- wallcycle_start_nocount(wcycle_, ewcLAUNCH_GPU);
- wallcycle_sub_start(wcycle_, ewcsLAUNCH_GPU_MOVEF);
+ // Communicate halo data
+ communicateHaloData(&(d_f_[atomOffset_]), fSendSize_, sendRankF_, recvPtr, fRecvSize_, recvRankF_);
- float3* d_f = d_f_;
- // If this is the last pulse and index (noting the force halo
- // exchanges across multiple pulses and indices are called in
- // reverse order) then perform the following preparation
- // activities
- if ((pulse_ == (dd_->comm->cd[dimIndex_].numPulses() - 1)) && (dimIndex_ == (dd_->ndim - 1)))
- {
- if (!accumulateForces)
- {
- // Clear local portion of force array (in local stream)
- cudaMemsetAsync(d_f, 0, numHomeAtoms_ * sizeof(rvec), localStream_.stream());
- }
+ wallcycle_stop(wcycle_, WallCycleCounter::MoveF);
- // ensure non-local stream waits for local stream, due to dependence on
- // the previous H2D copy of CPU forces (if accumulateForces is true)
- // or the above clearing.
- // TODO remove this dependency on localStream - edmine Issue #3093
- GpuEventSynchronizer eventLocal;
- eventLocal.markEvent(localStream_);
- eventLocal.enqueueWaitEvent(nonLocalStream_);
- }
+ wallcycle_start_nocount(wcycle_, WallCycleCounter::LaunchGpu);
+ wallcycle_sub_start(wcycle_, WallCycleSubCounter::LaunchGpuMoveF);
+
+ float3* d_f = d_f_;
// Unpack halo buffer into force array
const auto kernelArgs =
prepareGpuKernelArguments(kernelFn, config, &d_f, &recvBuf, &indexMap, &size);
- launchGpuKernel(kernelFn, config, nonLocalStream_, nullptr,
- "Domdec GPU Apply F Halo Exchange", kernelArgs);
+ launchGpuKernel(kernelFn, config, *haloStream_, nullptr, "Domdec GPU Apply F Halo Exchange", kernelArgs);
}
- if (pulse_ == 0)
- {
- fReadyOnDevice_.markEvent(nonLocalStream_);
- }
+ fReadyOnDevice_.markEvent(*haloStream_);
- wallcycle_sub_stop(wcycle_, ewcsLAUNCH_GPU_MOVEF);
- wallcycle_stop(wcycle_, ewcLAUNCH_GPU);
+ wallcycle_sub_stop(wcycle_, WallCycleSubCounter::LaunchGpuMoveF);
+ wallcycle_stop(wcycle_, WallCycleCounter::LaunchGpu);
}
-
-void GpuHaloExchange::Impl::communicateHaloData(float3* d_ptr,
- HaloQuantity haloQuantity,
- GpuEventSynchronizer* coordinatesReadyOnDeviceEvent)
+void GpuHaloExchange::Impl::communicateHaloData(float3* sendPtr,
+ int sendSize,
+ int sendRank,
+ float3* recvPtr,
+ int recvSize,
+ int recvRank)
{
-
- void* sendPtr;
- int sendSize;
- void* remotePtr;
- int sendRank;
- int recvRank;
-
- if (haloQuantity == HaloQuantity::HaloCoordinates)
+ if (GMX_THREAD_MPI)
{
- sendPtr = static_cast<void*>(d_sendBuf_);
- sendSize = xSendSize_;
- remotePtr = remoteXPtr_;
- sendRank = sendRankX_;
- recvRank = recvRankX_;
-
-#if GMX_MPI
- // Wait for event from receiving task that remote coordinates are ready, and enqueue that event to stream used
- // for subsequent data push. This avoids a race condition with the remote data being written in the previous timestep.
- // Similarly send event to task that will push data to this task.
- GpuEventSynchronizer* remoteCoordinatesReadyOnDeviceEvent;
- MPI_Sendrecv(&coordinatesReadyOnDeviceEvent, sizeof(GpuEventSynchronizer*), MPI_BYTE,
- recvRank, 0, &remoteCoordinatesReadyOnDeviceEvent, sizeof(GpuEventSynchronizer*),
- MPI_BYTE, sendRank, 0, mpi_comm_mysim_, MPI_STATUS_IGNORE);
- remoteCoordinatesReadyOnDeviceEvent->enqueueWaitEvent(nonLocalStream_);
-#else
- GMX_UNUSED_VALUE(coordinatesReadyOnDeviceEvent);
-#endif
+ // no need to explicitly sync with GMX_THREAD_MPI as all operations are
+ // anyway launched in correct stream
+ communicateHaloDataWithCudaDirect(sendPtr, sendSize, sendRank, recvPtr, recvRank);
}
else
{
- sendPtr = static_cast<void*>(&(d_ptr[atomOffset_]));
- sendSize = fSendSize_;
- remotePtr = remoteFPtr_;
- sendRank = sendRankF_;
- recvRank = recvRankF_;
+ communicateHaloDataWithCudaMPI(sendPtr, sendSize, sendRank, recvPtr, recvSize, recvRank);
+ }
+}
+
+void GpuHaloExchange::Impl::communicateHaloDataWithCudaMPI(float3* sendPtr,
+ int sendSize,
+ int sendRank,
+ float3* recvPtr,
+ int recvSize,
+ int recvRank)
+{
+ // no need to wait for haloDataReadyOnDevice event if this rank is not sending any data
+ if (sendSize > 0)
+ {
+ // wait for halo stream to complete all outstanding
+ // activities, to ensure that buffer is up-to-date in GPU memory
+ // before transferring to remote rank
+
+ // ToDo: Replace stream synchronize with event synchronize
+ haloStream_->synchronize();
}
- communicateHaloDataWithCudaDirect(sendPtr, sendSize, sendRank, remotePtr, recvRank);
+ // perform halo exchange directly in device buffers
+#if GMX_MPI
+ MPI_Request request;
+
+ // recv remote data into halo region
+ MPI_Irecv(recvPtr, recvSize * DIM, MPI_FLOAT, recvRank, 0, mpi_comm_mysim_, &request);
+
+ // send data to remote halo region
+ MPI_Send(sendPtr, sendSize * DIM, MPI_FLOAT, sendRank, 0, mpi_comm_mysim_);
+
+ MPI_Wait(&request, MPI_STATUS_IGNORE);
+#endif
}
-void GpuHaloExchange::Impl::communicateHaloDataWithCudaDirect(void* sendPtr,
- int sendSize,
- int sendRank,
- void* remotePtr,
- int recvRank)
+void GpuHaloExchange::Impl::communicateHaloDataWithCudaDirect(float3* sendPtr,
+ int sendSize,
+ int sendRank,
+ float3* remotePtr,
+ int recvRank)
{
cudaError_t stat;
// send data to neighbor, if any data exists to send
if (sendSize > 0)
{
- stat = cudaMemcpyAsync(remotePtr, sendPtr, sendSize * DIM * sizeof(float),
- cudaMemcpyDeviceToDevice, nonLocalStream_.stream());
+ stat = cudaMemcpyAsync(remotePtr,
+ sendPtr,
+ sendSize * DIM * sizeof(float),
+ cudaMemcpyDeviceToDevice,
+ haloStream_->stream());
CU_RET_ERR(stat, "cudaMemcpyAsync on GPU Domdec CUDA direct data transfer failed");
}
// to its stream.
GpuEventSynchronizer* haloDataTransferRemote;
- haloDataTransferLaunched_->markEvent(nonLocalStream_);
-
- MPI_Sendrecv(&haloDataTransferLaunched_, sizeof(GpuEventSynchronizer*), MPI_BYTE, sendRank, 0,
- &haloDataTransferRemote, sizeof(GpuEventSynchronizer*), MPI_BYTE, recvRank, 0,
- mpi_comm_mysim_, MPI_STATUS_IGNORE);
-
- haloDataTransferRemote->enqueueWaitEvent(nonLocalStream_);
+ GMX_ASSERT(haloDataTransferLaunched_ != nullptr,
+ "Halo exchange requires valid event to synchronize data transfer initiated in "
+ "remote rank");
+ haloDataTransferLaunched_->markEvent(*haloStream_);
+
+ MPI_Sendrecv(&haloDataTransferLaunched_,
+ sizeof(GpuEventSynchronizer*), //NOLINT(bugprone-sizeof-expression)
+ MPI_BYTE,
+ sendRank,
+ 0,
+ &haloDataTransferRemote,
+ sizeof(GpuEventSynchronizer*), //NOLINT(bugprone-sizeof-expression)
+ MPI_BYTE,
+ recvRank,
+ 0,
+ mpi_comm_mysim_,
+ MPI_STATUS_IGNORE);
+
+ haloDataTransferRemote->enqueueWaitEvent(*haloStream_);
#else
GMX_UNUSED_VALUE(sendRank);
GMX_UNUSED_VALUE(recvRank);
int dimIndex,
MPI_Comm mpi_comm_mysim,
const DeviceContext& deviceContext,
- const DeviceStream& localStream,
- const DeviceStream& nonLocalStream,
int pulse,
gmx_wallcycle* wcycle) :
dd_(dd),
sendRankF_(dd->neighbor[dimIndex][0]),
recvRankF_(dd->neighbor[dimIndex][1]),
usePBC_(dd->ci[dd->dim[dimIndex]] == 0),
- haloDataTransferLaunched_(new GpuEventSynchronizer()),
+ haloDataTransferLaunched_(GMX_THREAD_MPI ? new GpuEventSynchronizer() : nullptr),
mpi_comm_mysim_(mpi_comm_mysim),
deviceContext_(deviceContext),
- localStream_(localStream),
- nonLocalStream_(nonLocalStream),
+ haloStream_(new DeviceStream(deviceContext, DeviceStreamPriority::High, false)),
dimIndex_(dimIndex),
pulse_(pulse),
wcycle_(wcycle)
{
-
- GMX_RELEASE_ASSERT(GMX_THREAD_MPI,
- "GPU Halo exchange is currently only supported with thread-MPI enabled");
-
if (usePBC_ && dd->unitCellInfo.haveScrewPBC)
{
gmx_fatal(FARGS, "Error: screw is not yet supported in GPU halo exchange\n");
int dimIndex,
MPI_Comm mpi_comm_mysim,
const DeviceContext& deviceContext,
- const DeviceStream& localStream,
- const DeviceStream& nonLocalStream,
int pulse,
gmx_wallcycle* wcycle) :
- impl_(new Impl(dd, dimIndex, mpi_comm_mysim, deviceContext, localStream, nonLocalStream, pulse, wcycle))
+ impl_(new Impl(dd, dimIndex, mpi_comm_mysim, deviceContext, pulse, wcycle))
+{
+}
+
+GpuHaloExchange::GpuHaloExchange(GpuHaloExchange&&) noexcept = default;
+
+GpuHaloExchange& GpuHaloExchange::operator=(GpuHaloExchange&& other) noexcept
{
+ std::swap(impl_, other.impl_);
+ return *this;
}
GpuHaloExchange::~GpuHaloExchange() = default;
impl_->reinitHalo(asFloat3(d_coordinatesBuffer), asFloat3(d_forcesBuffer));
}
-void GpuHaloExchange::communicateHaloCoordinates(const matrix box,
- GpuEventSynchronizer* coordinatesReadyOnDeviceEvent)
+GpuEventSynchronizer* GpuHaloExchange::communicateHaloCoordinates(const matrix box,
+ GpuEventSynchronizer* dependencyEvent)
{
- impl_->communicateHaloCoordinates(box, coordinatesReadyOnDeviceEvent);
+ return impl_->communicateHaloCoordinates(box, dependencyEvent);
}
-void GpuHaloExchange::communicateHaloForces(bool accumulateForces)
+void GpuHaloExchange::communicateHaloForces(bool accumulateForces,
+ FixedCapacityVector<GpuEventSynchronizer*, 2>* dependencyEvents)
{
- impl_->communicateHaloForces(accumulateForces);
+ impl_->communicateHaloForces(accumulateForces, dependencyEvents);
}
GpuEventSynchronizer* GpuHaloExchange::getForcesReadyOnDeviceEvent()