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35 #ifndef GMX_GPU_UTILS_DEVICEBUFFER_SYCL_H
36 #define GMX_GPU_UTILS_DEVICEBUFFER_SYCL_H
38 /*! \libinternal \file
39 * \brief Implements the DeviceBuffer type and routines for SYCL.
40 * Should only be included directly by the main DeviceBuffer file devicebuffer.h.
41 * TODO: the intent is for DeviceBuffer to become a class.
43 * \author Artem Zhmurov <zhmurov@gmail.com>
44 * \author Erik Lindahl <erik.lindahl@gmail.com>
45 * \author Andrey Alekseenko <al42and@gmail.com>
52 #include "gromacs/gpu_utils/device_context.h"
53 #include "gromacs/gpu_utils/device_stream.h"
54 #include "gromacs/gpu_utils/devicebuffer_datatype.h"
55 #include "gromacs/gpu_utils/gmxsycl.h"
56 #include "gromacs/gpu_utils/gpu_utils.h" //only for GpuApiCallBehavior
57 #include "gromacs/gpu_utils/gputraits_sycl.h"
58 #include "gromacs/utility/gmxassert.h"
59 #include "gromacs/utility/stringutil.h"
63 class DeviceBuffer<T>::ClSyclBufferWrapper : public cl::sycl::buffer<T, 1>
65 using cl::sycl::buffer<T, 1>::buffer; // Get all the constructors
69 using ClSyclBufferWrapper = typename DeviceBuffer<T>::ClSyclBufferWrapper;
73 DeviceBuffer<T>::DeviceBuffer() : buffer_(nullptr)
79 DeviceBuffer<T>::~DeviceBuffer() = default;
81 //! Copy constructor (references the same underlying SYCL buffer).
83 DeviceBuffer<T>::DeviceBuffer(DeviceBuffer<T> const& src) :
84 buffer_(new ClSyclBufferWrapper(*src.buffer_))
90 DeviceBuffer<T>::DeviceBuffer(DeviceBuffer<T>&& src) noexcept = default;
92 //! Copy assignment (references the same underlying SYCL buffer).
94 DeviceBuffer<T>& DeviceBuffer<T>::operator=(DeviceBuffer<T> const& src)
96 buffer_.reset(new ClSyclBufferWrapper(*src.buffer_));
102 DeviceBuffer<T>& DeviceBuffer<T>::operator=(DeviceBuffer<T>&& src) noexcept = default;
104 /*! \brief Dummy assignment operator to allow compilation of some cross-platform code.
106 * A hacky way to make SYCL implementation of DeviceBuffer compatible with details of CUDA and
107 * OpenCL implementations.
109 * \todo Should be removed after DeviceBuffer refactoring.
111 * \tparam T Type of buffer content.
112 * \param nullPtr \c std::nullptr. Not possible to assign any other pointers.
115 DeviceBuffer<T>& DeviceBuffer<T>::operator=(std::nullptr_t nullPtr)
117 buffer_.reset(nullPtr);
122 namespace gmx::internal
124 //! Shorthand alias to create a placeholder SYCL accessor with chosen data type and access mode.
125 template<class T, enum cl::sycl::access::mode mode>
126 using PlaceholderAccessor =
127 cl::sycl::accessor<T, 1, mode, cl::sycl::access::target::global_buffer, cl::sycl::access::placeholder::true_t>;
128 } // namespace gmx::internal
131 * Thin wrapper around placeholder accessor that allows implicit construction from \c DeviceBuffer.
133 * "Placeholder accessor" is an indicator of the intent to create an accessor for certain buffer
134 * of a certain type, that is not yet bound to a specific command group handler (device). Such
135 * accessors can be created outside SYCL kernels, which is helpful if we want to pass them as
136 * function arguments.
138 * \tparam T Type of buffer content.
139 * \tparam mode Access mode.
141 template<class T, enum cl::sycl::access::mode mode>
142 class DeviceAccessor : public gmx::internal::PlaceholderAccessor<T, mode>
145 // Inherit all the constructors
146 using gmx::internal::PlaceholderAccessor<T, mode>::PlaceholderAccessor;
147 //! Construct Accessor from DeviceBuffer (must be initialized)
148 DeviceAccessor(DeviceBuffer<T>& buffer) :
149 gmx::internal::PlaceholderAccessor<T, mode>(getSyclBuffer(buffer))
154 //! Helper function to get sycl:buffer object from DeviceBuffer wrapper, with a sanity check.
155 static inline cl::sycl::buffer<T, 1>& getSyclBuffer(DeviceBuffer<T>& buffer)
157 GMX_ASSERT(bool(buffer), "Trying to construct accessor from an uninitialized buffer");
158 return *buffer.buffer_;
162 namespace gmx::internal
164 //! A "blackhole" class to be used when we want to ignore an argument to a function.
165 struct EmptyClassThatIgnoresConstructorArguments
167 template<class... Args>
168 [[maybe_unused]] EmptyClassThatIgnoresConstructorArguments(Args&&... /*args*/)
172 } // namespace gmx::internal
175 * Helper class to be used as function argument. Will either correspond to a device accessor, or an empty class.
179 template <bool doFoo>
180 void getBarKernel(handler& cgh, OptionalAccessor<float, mode::read, doFoo> a_fooPrms)
183 cgh.require(a_fooPrms);
184 // Can only use a_fooPrms if doFoo == true
187 template <bool doFoo>
188 void callBar(DeviceBuffer<float> b_fooPrms)
190 // If doFoo is false, b_fooPrms will be ignored (can be not initialized).
191 // Otherwise, an accessor will be built (b_fooPrms must be a valid buffer).
192 auto kernel = getBarKernel<doFoo>(b_fooPrms);
193 // If the accessor in not enabled, anything can be passed as its ctor argument.
194 auto kernel2 = getBarKernel<false>(nullptr_t);
198 * \tparam T Data type of the underlying buffer
199 * \tparam mode Access mode of the accessor
200 * \tparam enabled Compile-time flag indicating whether we want to actually create an accessor.
202 template<class T, enum cl::sycl::access::mode mode, bool enabled>
203 using OptionalAccessor =
204 std::conditional_t<enabled, DeviceAccessor<T, mode>, gmx::internal::EmptyClassThatIgnoresConstructorArguments>;
206 #endif // #ifndef DOXYGEN
208 /*! \brief Check the validity of the device buffer.
210 * Checks if the buffer is valid and if its allocation is big enough.
212 * \param[in] buffer Device buffer to be checked.
213 * \param[in] requiredSize Number of elements that the buffer will have to accommodate.
215 * \returns Whether the device buffer exists and has enough capacity.
218 static gmx_unused bool checkDeviceBuffer(const DeviceBuffer<T>& buffer, int requiredSize)
220 return buffer.buffer_ && (static_cast<int>(buffer.buffer_->get_count()) >= requiredSize);
223 /*! \libinternal \brief
224 * Allocates a device-side buffer.
225 * It is currently a caller's responsibility to call it only on not-yet allocated buffers.
227 * \tparam ValueType Raw value type of the \p buffer.
228 * \param[in,out] buffer Pointer to the device-side buffer.
229 * \param[in] numValues Number of values to accommodate.
230 * \param[in] deviceContext The buffer's device context-to-be.
232 template<typename ValueType>
233 void allocateDeviceBuffer(DeviceBuffer<ValueType>* buffer, size_t numValues, const DeviceContext& deviceContext)
235 /* SYCL does not require binding buffer to a specific context or device. The ::context_bound
236 * property only enforces the use of only given context, and possibly offers some optimizations */
237 const cl::sycl::property_list bufferProperties{ cl::sycl::property::buffer::context_bound(
238 deviceContext.context()) };
239 buffer->buffer_.reset(
240 new ClSyclBufferWrapper<ValueType>(cl::sycl::range<1>(numValues), bufferProperties));
244 * Frees a device-side buffer.
245 * This does not reset separately stored size/capacity integers,
246 * as this is planned to be a destructor of DeviceBuffer as a proper class,
247 * and no calls on \p buffer should be made afterwards.
249 * \param[in] buffer Pointer to the buffer to free.
251 template<typename ValueType>
252 void freeDeviceBuffer(DeviceBuffer<ValueType>* buffer)
254 buffer->buffer_.reset(nullptr);
258 * Performs the host-to-device data copy, synchronous or asynchronously on request.
260 * Unlike in CUDA and OpenCL, synchronous call does not guarantee that all previously
261 * submitted operations are complete, only the ones that are required for \p buffer consistency.
263 * \tparam ValueType Raw value type of the \p buffer.
264 * \param[in,out] buffer Pointer to the device-side buffer.
265 * \param[in] hostBuffer Pointer to the raw host-side memory, also typed \p ValueType.
266 * \param[in] startingOffset Offset (in values) at the device-side buffer to copy into.
267 * \param[in] numValues Number of values to copy.
268 * \param[in] deviceStream GPU stream to perform asynchronous copy in.
269 * \param[in] transferKind Copy type: synchronous or asynchronous.
270 * \param[out] timingEvent A pointer to the H2D copy timing event to be filled in.
273 template<typename ValueType>
274 void copyToDeviceBuffer(DeviceBuffer<ValueType>* buffer,
275 const ValueType* hostBuffer,
276 size_t startingOffset,
278 const DeviceStream& deviceStream,
279 GpuApiCallBehavior transferKind,
280 CommandEvent* gmx_unused timingEvent)
284 return; // such calls are actually made with empty domains
286 GMX_ASSERT(buffer, "needs a buffer pointer");
287 GMX_ASSERT(hostBuffer, "needs a host buffer pointer");
289 GMX_ASSERT(checkDeviceBuffer(*buffer, startingOffset + numValues),
290 "buffer too small or not initialized");
292 cl::sycl::buffer<ValueType>& syclBuffer = *buffer->buffer_;
294 cl::sycl::event ev = deviceStream.stream().submit([&](cl::sycl::handler& cgh) {
295 /* Here and elsewhere in this file, accessor constructor is user instead of a more common
296 * buffer::get_access, since the compiler (icpx 2021.1-beta09) occasionally gets confused
297 * by all the overloads */
298 auto d_bufferAccessor = cl::sycl::accessor<ValueType, 1, cl::sycl::access::mode::discard_write>{
299 syclBuffer, cgh, cl::sycl::range(numValues), cl::sycl::id(startingOffset)
301 cgh.copy(hostBuffer, d_bufferAccessor);
303 if (transferKind == GpuApiCallBehavior::Sync)
310 * Performs the device-to-host data copy, synchronous or asynchronously on request.
312 * Unlike in CUDA and OpenCL, synchronous call does not guarantee that all previously
313 * submitted operations are complete, only the ones that are required for \p buffer consistency.
315 * \tparam ValueType Raw value type of the \p buffer.
316 * \param[in,out] hostBuffer Pointer to the raw host-side memory, also typed \p ValueType
317 * \param[in] buffer Pointer to the device-side buffer.
318 * \param[in] startingOffset Offset (in values) at the device-side buffer to copy from.
319 * \param[in] numValues Number of values to copy.
320 * \param[in] deviceStream GPU stream to perform asynchronous copy in.
321 * \param[in] transferKind Copy type: synchronous or asynchronous.
322 * \param[out] timingEvent A pointer to the H2D copy timing event to be filled in.
325 template<typename ValueType>
326 void copyFromDeviceBuffer(ValueType* hostBuffer,
327 DeviceBuffer<ValueType>* buffer,
328 size_t startingOffset,
330 const DeviceStream& deviceStream,
331 GpuApiCallBehavior transferKind,
332 CommandEvent* gmx_unused timingEvent)
336 return; // such calls are actually made with empty domains
338 GMX_ASSERT(buffer, "needs a buffer pointer");
339 GMX_ASSERT(hostBuffer, "needs a host buffer pointer");
341 GMX_ASSERT(checkDeviceBuffer(*buffer, startingOffset + numValues),
342 "buffer too small or not initialized");
344 cl::sycl::buffer<ValueType>& syclBuffer = *buffer->buffer_;
346 cl::sycl::event ev = deviceStream.stream().submit([&](cl::sycl::handler& cgh) {
347 const auto d_bufferAccessor = cl::sycl::accessor<ValueType, 1, cl::sycl::access::mode::read>{
348 syclBuffer, cgh, cl::sycl::range(numValues), cl::sycl::id(startingOffset)
350 cgh.copy(d_bufferAccessor, hostBuffer);
352 if (transferKind == GpuApiCallBehavior::Sync)
359 namespace gmx::internal
361 /*! \brief Helper function to clear device buffer.
363 * Not applicable to GROMACS's float3 (a.k.a. gmx::RVec) and other custom types.
364 * From SYCL specs: "T must be a scalar value or a SYCL vector type."
366 template<typename ValueType>
367 cl::sycl::event fillSyclBufferWithNull(cl::sycl::buffer<ValueType, 1>& buffer,
368 size_t startingOffset,
370 cl::sycl::queue queue)
372 using cl::sycl::access::mode;
373 const cl::sycl::range<1> range(numValues);
374 const cl::sycl::id<1> offset(startingOffset);
375 const ValueType pattern = ValueType(0); // SYCL vectors support initialization by scalar
377 return queue.submit([&](cl::sycl::handler& cgh) {
378 auto d_bufferAccessor =
379 cl::sycl::accessor<ValueType, 1, mode::discard_write>{ buffer, cgh, range, offset };
380 cgh.fill(d_bufferAccessor, pattern);
384 //! \brief Helper function to clear device buffer of type float3.
386 inline cl::sycl::event fillSyclBufferWithNull(cl::sycl::buffer<Float3, 1>& buffer,
387 size_t startingOffset,
389 cl::sycl::queue queue)
391 cl::sycl::buffer<float, 1> bufferAsFloat = buffer.reinterpret<float, 1>(buffer.get_count() * DIM);
392 return fillSyclBufferWithNull<float>(
393 bufferAsFloat, startingOffset * DIM, numValues * DIM, std::move(queue));
395 } // namespace gmx::internal
398 * Clears the device buffer asynchronously.
400 * \tparam ValueType Raw value type of the \p buffer.
401 * \param[in,out] buffer Pointer to the device-side buffer.
402 * \param[in] startingOffset Offset (in values) at the device-side buffer to start clearing at.
403 * \param[in] numValues Number of values to clear.
404 * \param[in] deviceStream GPU stream.
406 template<typename ValueType>
407 void clearDeviceBufferAsync(DeviceBuffer<ValueType>* buffer,
408 size_t startingOffset,
410 const DeviceStream& deviceStream)
416 GMX_ASSERT(buffer, "needs a buffer pointer");
418 GMX_ASSERT(checkDeviceBuffer(*buffer, startingOffset + numValues),
419 "buffer too small or not initialized");
421 cl::sycl::buffer<ValueType>& syclBuffer = *(buffer->buffer_);
423 gmx::internal::fillSyclBufferWithNull<ValueType>(
424 syclBuffer, startingOffset, numValues, deviceStream.stream());
427 /*! \brief Create a texture object for an array of type ValueType.
429 * Creates the device buffer and copies read-only data for an array of type ValueType.
430 * Like OpenCL, does not really do anything with textures, simply creates a buffer
431 * and initializes it.
433 * \tparam ValueType Raw data type.
435 * \param[out] deviceBuffer Device buffer to store data in.
436 * \param[in] hostBuffer Host buffer to get date from.
437 * \param[in] numValues Number of elements in the buffer.
438 * \param[in] deviceContext GPU device context.
440 template<typename ValueType>
441 void initParamLookupTable(DeviceBuffer<ValueType>* deviceBuffer,
442 DeviceTexture* /* deviceTexture */,
443 const ValueType* hostBuffer,
445 const DeviceContext& deviceContext)
447 GMX_ASSERT(hostBuffer, "Host buffer should be specified.");
448 GMX_ASSERT(deviceBuffer, "Device buffer should be specified.");
450 /* Constructing buffer with cl::sycl::buffer(T* data, size_t size) will take ownership
451 * of this memory region making it unusable, which might lead to side-effects.
452 * On the other hand, cl::sycl::buffer(InputIterator<T> begin, InputIterator<T> end) will
453 * initialize the buffer without affecting ownership of the memory, although
454 * it will consume extra memory on host. */
455 const cl::sycl::property_list bufferProperties{ cl::sycl::property::buffer::context_bound(
456 deviceContext.context()) };
457 deviceBuffer->buffer_.reset(new ClSyclBufferWrapper<ValueType>(
458 hostBuffer, hostBuffer + numValues, bufferProperties));
461 /*! \brief Release the OpenCL device buffer.
463 * \tparam ValueType Raw data type.
465 * \param[in,out] deviceBuffer Device buffer to store data in.
467 template<typename ValueType>
468 void destroyParamLookupTable(DeviceBuffer<ValueType>* deviceBuffer, DeviceTexture& /* deviceTexture */)
470 deviceBuffer->buffer_.reset(nullptr);
473 #endif // GMX_GPU_UTILS_DEVICEBUFFER_SYCL_H