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35 /*! \libinternal \file
36 * \brief Implements a GpuEventSynchronizer class for CUDA.
38 * \author Aleksei Iupinov <a.yupinov@gmail.com>
41 #ifndef GMX_GPU_UTILS_GPUEVENTSYNCHRONIZER_CUH
42 #define GMX_GPU_UTILS_GPUEVENTSYNCHRONIZER_CUH
44 #include "gromacs/gpu_utils/gputraits.cuh"
45 #include "gromacs/utility/gmxassert.h"
47 /*! \libinternal \brief
48 * A class which allows for CPU thread to mark and wait for certain GPU stream execution point.
49 * The event can be put into the stream with markEvent() and then later waited on with waitForEvent().
50 * This can be repeated as necessary, but the current implementation does not allow waiting on
51 * completed event more than once, expecting only exact pairs of markEvent(stream); waitForEvent().
52 * The class generally attempts to track the correctness of its state transitions, but
53 * please note that calling waitForEvent() right after the construction will succeed with CUDA but fail with OpenCL.
55 * Another possible mode of operation can be implemented if needed:
56 * multiple calls to waitForEvent() after a single markEvent().
57 * For this, only some small alterations to gpueventsynchronizer_ocl.h need to be made.
58 * This was tested to work both with CUDA and NVidia OpenCL, but not with AMD/Intel OpenCL.
60 class GpuEventSynchronizer
63 GpuEventSynchronizer()
65 cudaError_t gmx_used_in_debug stat = cudaEventCreateWithFlags(&event_, cudaEventDisableTiming);
66 GMX_RELEASE_ASSERT(stat == cudaSuccess, "cudaEventCreate failed");
68 ~GpuEventSynchronizer()
70 cudaError_t gmx_used_in_debug stat = cudaEventDestroy(event_);
71 GMX_ASSERT(stat == cudaSuccess, "cudaEventDestroy failed");
74 GpuEventSynchronizer(const GpuEventSynchronizer&) = delete;
76 GpuEventSynchronizer& operator=(GpuEventSynchronizer&&) = delete;
77 //! Moving is disabled but can be considered in the future if needed
78 GpuEventSynchronizer(GpuEventSynchronizer&&) = delete;
80 /*! \brief Marks the synchronization point in the \p stream.
81 * Should be followed by waitForEvent().
83 inline void markEvent(const DeviceStream& deviceStream)
85 cudaError_t gmx_used_in_debug stat = cudaEventRecord(event_, deviceStream.stream());
86 GMX_ASSERT(stat == cudaSuccess, "cudaEventRecord failed");
88 /*! \brief Synchronizes the host thread on the marked event. */
89 inline void waitForEvent()
91 cudaError_t gmx_used_in_debug stat = cudaEventSynchronize(event_);
92 GMX_ASSERT(stat == cudaSuccess, "cudaEventSynchronize failed");
94 /*! \brief Enqueues a wait for the recorded event in stream \p stream */
95 inline void enqueueWaitEvent(const DeviceStream& deviceStream)
97 cudaError_t gmx_used_in_debug stat = cudaStreamWaitEvent(deviceStream.stream(), event_, 0);
98 GMX_ASSERT(stat == cudaSuccess, "cudaStreamWaitEvent failed");