[Feature] Make TensorAdapter Stream Aware (#4472)

* Allocate tensors in DGL's current stream

* make tensoradaptor stream-aware

* replace TAemtpy with cpu allocator

* fix typo

* try fix cpu allocation

* clean header

* redirect AllocDataSpace as well

* resolve comments

include/dgl/runtime/tensordispatch.h

 /*!
- *  Copyright (c) 2020 by Contributors
+ *  Copyright (c) 2020-2022 by Contributors
  * \file array/tensordispatch.h
  * \brief This file defines the dispatcher of tensor operators to framework-specific
  *  implementations.
@@ -8,8 +8,6 @@
  *  one separately-built shared library per supported backend.
  *
  *  Those shared libraries contain wrappers of the framework-specific operators.
- *  The wrappers have almost the same signatures as functions in aten namespace,
- *  except that they accept and return DLManagedTensors instead of NDArrays.
  *  The wrappers are defined with extern "C", meaning that the C++ compiler will
  *  not do name mangling for those functions so that DGL can conveniently locate
  *  them using dlsym(3) (or GetProcAddress in Windows).
@@ -23,21 +21,21 @@
  *
  *  A tensor operator in TensorDispatcher first checks whether the corresponding symbol
  *  address is found in the mapping.  If so, it calls the function located at the
- *  symbol address instead, translating NDArrays to DLManagedTensors using
- *  NDArray::ToDLPack(), and translates the DLManagedTensors in the return values
- *  back to NDArrays using NDArray::FromDLPack().  If not, it falls back to the
- *  implementation in dgl::aten namespace.
+ *  symbol address instead, allocate/free pieces of memory on CPU/GPU.
+ *  If not, it falls back to DeviceAPI::AllocWorkspace/FreeWorkspace.
  */
 
 #ifndef DGL_RUNTIME_TENSORDISPATCH_H_
 #define DGL_RUNTIME_TENSORDISPATCH_H_
 
-#include <dlpack/dlpack.h>
+#include <stddef.h>
 #include <tensoradapter.h>
 #if defined(WIN32) || defined(_WIN32)
 #include <windows.h>
 #endif  // WIN32
-#include <vector>
+#ifdef DGL_USE_CUDA
+#include <cuda_runtime.h>
+#endif  // DGL_USE_CUDA
 #include "ndarray.h"
 
 /*! \brief Casts a pointer \c entry to a function pointer with signature of \c func */
@@ -68,18 +66,27 @@ class TensorDispatcher {
   bool Load(const char *path_cstr);
 
   /*!
-   * \brief Allocate an empty tensor.
-   * Used in NDArray::Empty().
+   * \brief Allocate a piece of CPU memory via
+   * PyTorch's CPUAllocator.
+   * Used in CPUDeviceAPI::AllocWorkspace().
+   *
+   * \param nbytes The size to be allocated.
+   * \return Pointer to the allocated memory.
+   */
+  inline void* CPUAllocWorkspace(size_t nbytes) {
+    auto entry = entrypoints_[Op::kCPURawAlloc];
+    return FUNCCAST(tensoradapter::CPURawAlloc, entry)(nbytes);
+  }
 
-   * \param shape The shape
-   * \param dtype The data type
-   * \param ctx The device
-   * \return An empty NDArray.
+  /*!
+   * \brief Free the CPU memory.
+   * Used in CPUDeviceAPI::FreeWorkspace().
+   *
+   * \param ptr Pointer to the memory to be freed.
    */
-  inline NDArray Empty(std::vector<int64_t> shape, DLDataType dtype, DLContext ctx) const {
-    auto entry = entrypoints_[Op::kEmpty];
-    auto result = FUNCCAST(tensoradapter::TAempty, entry)(shape, dtype, ctx);
-    return NDArray::FromDLPack(result);
+  inline void CPUFreeWorkspace(void* ptr) {
+    auto entry = entrypoints_[Op::kCPURawDelete];
+    FUNCCAST(tensoradapter::CPURawDelete, entry)(ptr);
   }
 
 #ifdef DGL_USE_CUDA
@@ -93,11 +100,12 @@ class TensorDispatcher {
    * before invoking this function.
    *
    * \param nbytes The size to be allocated.
+   * \param stream The stream to be allocated on.
    * \return Pointer to the allocated memory.
    */
-  inline void* AllocWorkspace(size_t nbytes) {
-    auto entry = entrypoints_[Op::kRawAlloc];
-    return FUNCCAST(tensoradapter::RawAlloc, entry)(nbytes);
+  inline void* CUDAAllocWorkspace(size_t nbytes, cudaStream_t stream) {
+    auto entry = entrypoints_[Op::kCUDARawAlloc];
+    return FUNCCAST(tensoradapter::CUDARawAlloc, entry)(nbytes, stream);
   }
 
   /*!
@@ -106,9 +114,9 @@ class TensorDispatcher {
    *
    * \param ptr Pointer to the memory to be freed.
    */
-  inline void FreeWorkspace(void* ptr) {
-    auto entry = entrypoints_[Op::kRawDelete];
-    FUNCCAST(tensoradapter::RawDelete, entry)(ptr);
+  inline void CUDAFreeWorkspace(void* ptr) {
+    auto entry = entrypoints_[Op::kCUDARawDelete];
+    FUNCCAST(tensoradapter::CUDARawDelete, entry)(ptr);
   }
 #endif  // DGL_USE_CUDA
 
@@ -124,20 +132,22 @@ class TensorDispatcher {
    * Must match the functions in tensoradapter/include/tensoradapter.h.
    */
   static constexpr const char *names_[] = {
-    "TAempty",
+    "CPURawAlloc",
+    "CPURawDelete",
 #ifdef DGL_USE_CUDA
-    "RawAlloc",
-    "RawDelete",
+    "CUDARawAlloc",
+    "CUDARawDelete",
 #endif  // DGL_USE_CUDA
   };
 
   /*! \brief Index of each function to the symbol list */
   class Op {
    public:
-    static constexpr int kEmpty = 0;
+    static constexpr int kCPURawAlloc = 0;
+    static constexpr int kCPURawDelete = 1;
 #ifdef DGL_USE_CUDA
-    static constexpr int kRawAlloc = 1;
-    static constexpr int kRawDelete = 2;
+    static constexpr int kCUDARawAlloc = 2;
+    static constexpr int kCUDARawDelete = 3;
 #endif  // DGL_USE_CUDA
   };
 
@@ -147,6 +157,7 @@ class TensorDispatcher {
   /*! \brief Entrypoints of each function */
   void* entrypoints_[num_entries_] = {
     nullptr,
+    nullptr,
 #ifdef DGL_USE_CUDA
     nullptr,
     nullptr,

src/runtime/cpu_device_api.cc

 /*!
- *  Copyright (c) 2016 by Contributors
+ *  Copyright (c) 2016-2022 by Contributors
  * \file cpu_device_api.cc
  */
 #include <dmlc/logging.h>
 #include <dmlc/thread_local.h>
 #include <dgl/runtime/registry.h>
 #include <dgl/runtime/device_api.h>
+#include <dgl/runtime/tensordispatch.h>
 #include <cstdlib>
 #include <cstring>
 #include "workspace_pool.h"
@@ -24,6 +25,10 @@ class CPUDeviceAPI final : public DeviceAPI {
                        size_t nbytes,
                        size_t alignment,
                        DGLType type_hint) final {
+    TensorDispatcher* td = TensorDispatcher::Global();
+    if (td->IsAvailable())
+      return td->CPUAllocWorkspace(nbytes);
+
     void* ptr;
 #if _MSC_VER || defined(__MINGW32__)
     ptr = _aligned_malloc(nbytes, alignment);
@@ -39,6 +44,10 @@ class CPUDeviceAPI final : public DeviceAPI {
   }
 
   void FreeDataSpace(DGLContext ctx, void* ptr) final {
+    TensorDispatcher* td = TensorDispatcher::Global();
+    if (td->IsAvailable())
+      return td->CPUFreeWorkspace(ptr);
+
 #if _MSC_VER || defined(__MINGW32__)
     _aligned_free(ptr);
 #else
@@ -83,11 +92,18 @@ struct CPUWorkspacePool : public WorkspacePool {
 void* CPUDeviceAPI::AllocWorkspace(DGLContext ctx,
                                    size_t size,
                                    DGLType type_hint) {
-  return dmlc::ThreadLocalStore<CPUWorkspacePool>::Get()
-      ->AllocWorkspace(ctx, size);
+  TensorDispatcher* td = TensorDispatcher::Global();
+  if (td->IsAvailable())
+    return td->CPUAllocWorkspace(size);
+
+  return dmlc::ThreadLocalStore<CPUWorkspacePool>::Get()->AllocWorkspace(ctx, size);
 }
 
 void CPUDeviceAPI::FreeWorkspace(DGLContext ctx, void* data) {
+  TensorDispatcher* td = TensorDispatcher::Global();
+  if (td->IsAvailable())
+    return td->CPUFreeWorkspace(data);
+
   dmlc::ThreadLocalStore<CPUWorkspacePool>::Get()->FreeWorkspace(ctx, data);
 }
 

src/runtime/cuda/cuda_device_api.cc

 /*!
- *  Copyright (c) 2017 by Contributors
+ *  Copyright (c) 2017-2022 by Contributors
  * \file cuda_device_api.cc
  * \brief GPU specific API
  */
@@ -107,7 +107,12 @@ class CUDADeviceAPI final : public DeviceAPI {
                        size_t nbytes,
                        size_t alignment,
                        DGLType type_hint) final {
-    CUDA_CALL(cudaSetDevice(ctx.device_id));
+    SetDevice(ctx);
+    // Redirect to PyTorch's allocator when available.
+    TensorDispatcher* td = TensorDispatcher::Global();
+    if (td->IsAvailable())
+      return td->CUDAAllocWorkspace(nbytes, CUDAThreadEntry::ThreadLocal()->stream);
+
     CHECK_EQ(256 % alignment, 0U)
         << "CUDA space is aligned at 256 bytes";
     void *ret;
@@ -116,7 +121,11 @@ class CUDADeviceAPI final : public DeviceAPI {
   }
 
   void FreeDataSpace(DGLContext ctx, void* ptr) final {
-    CUDA_CALL(cudaSetDevice(ctx.device_id));
+    SetDevice(ctx);
+    TensorDispatcher* td = TensorDispatcher::Global();
+    if (td->IsAvailable())
+      return td->CUDAFreeWorkspace(ptr);
+
     CUDA_CALL(cudaFree(ptr));
   }
 
@@ -246,20 +255,21 @@ class CUDADeviceAPI final : public DeviceAPI {
   }
 
   void* AllocWorkspace(DGLContext ctx, size_t size, DGLType type_hint) final {
-    // Redirect to PyTorch's allocator when available.
     SetDevice(ctx);
+    // Redirect to PyTorch's allocator when available.
     TensorDispatcher* td = TensorDispatcher::Global();
     if (td->IsAvailable())
-      return td->AllocWorkspace(size);
-    else
+      return td->CUDAAllocWorkspace(size, CUDAThreadEntry::ThreadLocal()->stream);
+
     return CUDAThreadEntry::ThreadLocal()->pool.AllocWorkspace(ctx, size);
   }
 
   void FreeWorkspace(DGLContext ctx, void* data) final {
+    SetDevice(ctx);
     TensorDispatcher* td = TensorDispatcher::Global();
     if (td->IsAvailable())
-      td->FreeWorkspace(data);
-    else
+      return td->CUDAFreeWorkspace(data);
+
     CUDAThreadEntry::ThreadLocal()->pool.FreeWorkspace(ctx, data);
   }
 

src/runtime/ndarray.cc

 /*!
- *  Copyright (c) 2017 by Contributors
+ *  Copyright (c) 2017-2022 by Contributors
  * \file ndarray.cc
  * \brief NDArray container infratructure.
  */
@@ -214,10 +214,6 @@ NDArray NDArray::EmptyShared(const std::string &name,
 NDArray NDArray::Empty(std::vector<int64_t> shape,
                        DLDataType dtype,
                        DLContext ctx) {
-  TensorDispatcher* td = TensorDispatcher::Global();
-  if (td->IsAvailable())
-    return td->Empty(shape, dtype, ctx);
-
   NDArray ret = Internal::Create(shape, dtype, ctx);
   // setup memory content
   size_t size = GetDataSize(ret.data_->dl_tensor);

tensoradapter/include/tensoradapter.h

 /*!
- *  Copyright (c) 2020 by Contributors
+ *  Copyright (c) 2020-2022 by Contributors
  * \file tensoradapter.h
  * \brief Header file for functions exposed by the adapter library.
  *
@@ -10,23 +10,29 @@
 #ifndef TENSORADAPTER_H_
 #define TENSORADAPTER_H_
 
-#include <dlpack/dlpack.h>
-#include <vector>
+#ifdef DGL_USE_CUDA
+#include <cuda_runtime.h>
+#endif  // DGL_USE_CUDA
 
 namespace tensoradapter {
 
 extern "C" {
 
 /*!
- * \brief Allocate an empty tensor.
+ * \brief Allocate a piece of CPU memory via
+ * PyTorch's CPUAllocator
  *
- * \param shape The shape
- * \param dtype The data type
- * \param ctx The device
- * \return The allocated tensor
+ * \param nbytes The size to be allocated.
+ * \return Pointer to the allocated memory.
+ */
+void* CPURawAlloc(size_t nbytes);
+
+/*!
+ * \brief Free the CPU memory.
+ *
+ * \param ptr Pointer to the memory to be freed.
  */
-DLManagedTensor* TAempty(
-    std::vector<int64_t> shape, DLDataType dtype, DLContext ctx);
+void CPURawDelete(void* ptr);
 
 #ifdef DGL_USE_CUDA
 /*!
@@ -34,16 +40,17 @@ DLManagedTensor* TAempty(
  * PyTorch's THCCachingAllocator.
  *
  * \param nbytes The size to be allocated.
+ * \param stream The stream to be allocated on.
  * \return Pointer to the allocated memory.
  */
-void* RawAlloc(size_t nbytes);
+void* CUDARawAlloc(size_t nbytes, cudaStream_t stream);
 
 /*!
  * \brief Free the GPU memory.
  *
  * \param ptr Pointer to the memory to be freed.
  */
-void RawDelete(void* ptr);
+void CUDARawDelete(void* ptr);
 #endif  // DGL_USE_CUDA
 
 }

tensoradapter/pytorch/torch.cpp

 /*!
- *  Copyright (c) 2020 by Contributors
+ *  Copyright (c) 2020-2022 by Contributors
  * \file torch/torch.cpp
  * \brief Implementation of PyTorch adapter library.
  */
 
 #include <tensoradapter_exports.h>
-#include <torch/torch.h>
-#include <ATen/DLConvertor.h>
+#include <c10/core/CPUAllocator.h>
 #ifdef DGL_USE_CUDA
 #include <c10/cuda/CUDACachingAllocator.h>
+#include <cuda_runtime.h>
 #endif  // DGL_USE_CUDA
-#include <vector>
-#include <iostream>
-
-#if DLPACK_VERSION > 040
-// Compatibility across DLPack - note that this assumes that the ABI stays the same.
-#define kDLGPU kDLCUDA
-#define DLContext DLDevice
-#endif
 
 namespace tensoradapter {
 
-static at::Device get_device(DLContext ctx) {
-  switch (ctx.device_type) {
-   case kDLCPU:
-    return at::Device(torch::kCPU);
-    break;
-   case kDLGPU:
-    return at::Device(torch::kCUDA, ctx.device_id);
-    break;
-   default:
-    // fallback to CPU
-    return at::Device(torch::kCPU);
-    break;
-  }
-}
-
 extern "C" {
 
-TA_EXPORTS DLManagedTensor* TAempty(
-    std::vector<int64_t> shape,
-    DLDataType dtype,
-    DLContext ctx) {
-  auto options = torch::TensorOptions()
-    .layout(torch::kStrided)
-    .device(get_device(ctx))
-    .dtype(at::toScalarType(dtype));
-  torch::Tensor tensor = torch::empty(shape, options);
-  return at::toDLPack(tensor);
+TA_EXPORTS void* CPURawAlloc(size_t nbytes) {
+  return c10::GetCPUAllocator()->raw_allocate(nbytes);
+}
+
+TA_EXPORTS void CPURawDelete(void* ptr) {
+  c10::GetCPUAllocator()->raw_deallocate(ptr);
 }
 
 #ifdef DGL_USE_CUDA
-TA_EXPORTS void* RawAlloc(size_t nbytes) {
-  return c10::cuda::CUDACachingAllocator::raw_alloc(nbytes);
+TA_EXPORTS void* CUDARawAlloc(size_t nbytes, cudaStream_t stream) {
+  return c10::cuda::CUDACachingAllocator::raw_alloc_with_stream(
+    nbytes, stream);
 }
 
-TA_EXPORTS void RawDelete(void* ptr) {
+TA_EXPORTS void CUDARawDelete(void* ptr) {
   c10::cuda::CUDACachingAllocator::raw_delete(ptr);
 }
 #endif  // DGL_USE_CUDA