Merge pull request #162 from LLNL/release/2.2.2

Release v2.2.2

Author: davidbeckingsale

CMakeLists.txt

@@ -7,7 +7,7 @@
 cmake_policy(SET CMP0057 NEW)
 cmake_policy(SET CMP0048 NEW)
 
-project(Chai LANGUAGES CXX VERSION 2.2.1)
+project(Chai LANGUAGES CXX VERSION 2.2.2)
 
 set(ENABLE_CUDA Off CACHE BOOL "Enable CUDA")
 set(ENABLE_HIP Off CACHE BOOL "Enable HIP")

docs/sphinx/conf.py

@@ -63,7 +63,7 @@
 # The short X.Y version.
 version = u'2.2'
 # The full version, including alpha/beta/rc tags.
-release = u'2.2.1'
+release = u'2.2.2'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.

docs/sphinx/conf.py.in

@@ -62,7 +62,7 @@ author = u''
 # The short X.Y version.
 version = u'2.2'
 # The full version, including alpha/beta/rc tags.
-release = u'2.2.1'
+release = u'2.2.2'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.

docs/sphinx/index.rst

@@ -63,6 +63,7 @@ Any questions? Contact chai-dev@llnl.gov
 
   getting_started
   tutorial
+  user_guide
 
 .. toctree::
   :maxdepth: 2

docs/sphinx/user_guide.rst

@@ -0,0 +1,269 @@
+.. Copyright (c) 2016, Lawrence Livermore National Security, LLC. All
+ rights reserved.
+ 
+ Produced at the Lawrence Livermore National Laboratory
+ 
+ This file is part of CHAI.
+ 
+ LLNL-CODE-705877
+ 
+ For details, see https:://github.com/LLNL/CHAI
+ Please also see the NOTICE and LICENSE files.
+ 
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+ 
+ - Redistributions of source code must retain the above copyright
+   notice, this list of conditions and the following disclaimer.
+ 
+ - Redistributions in binary form must reproduce the above copyright
+   notice, this list of conditions and the following disclaimer in the
+   documentation and/or other materials provided with the
+   distribution.
+ 
+ - Neither the name of the LLNS/LLNL nor the names of its contributors
+   may be used to endorse or promote products derived from this
+   software without specific prior written permission.
+ 
+ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
+ WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ POSSIBILITY OF SUCH DAMAGE.
+
+.. _user_guide:
+
+**********
+User Guide
+**********
+
+-----------------------------------
+A Portable Pattern for Polymorphism
+-----------------------------------
+
+CHAI provides a data structure to help handle cases where it is desirable to call virtual functions on the device. If you only call virtual functions on the host, this pattern is unnecessary. But for those who do want to use virtual functions on the device without a painstaking amount of refactoring, we begin with a short, albeit admittedly contrived example.
+
+.. code-block:: cpp
+
+   class MyBaseClass {
+      public:
+         MyBaseClass() {}
+         virtual ~MyBaseClass() {}
+         virtual int getValue() const = 0;
+   };
+
+   class MyDerivedClass : public MyBaseClass {
+      public:
+         MyDerivedClass(int value) : MyBaseClass(), m_value(value) {}
+         ~MyDerivedClass() {}
+         int getValue() const { return m_value; }
+
+      private:
+         int m_value;
+   };
+
+   int main(int argc, char** argv) {
+      MyBaseClass* myBaseClass = new MyDerivedClass(0);
+      myBaseClass->getValue();
+      delete myBaseClass;
+      return 0;
+   }
+
+It is perfectly fine to call `myBaseClass->getValue()` in host code, since `myBaseClass` was created on the host. However, what if you want to call this virtual function on the device?
+
+.. code-block:: cpp
+
+   __global__ void callVirtualFunction(MyBaseClass* myBaseClass) {
+      myBaseClass->getValue();
+   }
+
+   int main(int argc, char** argv) {
+      MyBaseClass* myBaseClass = new MyDerivedClass(0);
+      callVirtualFunction<<<1, 1>>>(myBaseClass);
+      delete myBaseClass;
+      return 0;
+   }
+
+At best, calling this code will result in a crash. At worst, it will access garbage and happily continue while giving incorrect results. It is illegal to access host pointers on the device and produces undefined behavior. So what is our next attempt? Why not pass the argument by value rather than by a pointer?
+
+.. code-block:: cpp
+
+   __global__ void callVirtualFunction(MyBaseClass myBaseClass) {
+      myBaseClass.getValue();
+   }
+
+   int main(int argc, char** argv) {
+      MyBaseClass* myBaseClass = new MyDerivedClass(0);
+      callVirtualFunction<<<1, 1>>>(*myBaseClass); // This will not compile
+      delete myBaseClass;
+      return 0;
+   }
+
+At first glance, this may seem like it would work, but this is not supported by nvidia: "It is not allowed to pass as an argument to a `__global__` function an object of a class with virtual functions" (https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#virtual-functions). Also: "It is not allowed to pass as an argument to a `__global__` function an object of a class derived from virtual base classes" (https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#virtual-base-classes). You could refactor to use the curiously recurring template pattern, but that would likely require a large development effort and also limits the programming patterns you can use. Also, there is a limitation on the size of the arguments passed to a global kernel, so if you have a very large class this is simply impossible. So we make another attempt.
+
+.. code-block:: cpp
+
+   __global__ void callVirtualFunction(MyBaseClass* myBaseClass) {
+      myBaseClass->getValue();
+   }
+
+   int main(int argc, char** argv) {
+      MyBaseClass* myBaseClass = new MyDerivedClass(0);
+      MyBaseClass* d_myBaseClass;
+      cudaMalloc(&d_myBaseClass, sizeof(MyBaseClass));
+      cudaMemcpy(d_myBaseClass, myBaseClass, sizeof(MyBaseClass), cudaMemcpyHostToDevice);
+
+      callVirtualFunction<<<1, 1>>>(d_myBaseClass);
+
+      cudaFree(d_myBaseClass);
+      delete myBaseClass;
+
+      return 0;
+   }
+
+We are getting nearer, but there is still a flaw. The bits of `myBaseClass` contain the virtual function table that allows virtual function lookups on the host, but that virtual function table is not valid for lookups on the device since it contains pointers to host functions. It will not work any better to cast to `MyDerivedClass` and copy the bits. The only option is to call the constructor on the device and keep that device pointer around.
+
+.. code-block:: cpp
+
+   __global__ void make_on_device(MyBaseClass** myBaseClass, int argument) {
+      *myBaseClass = new MyDerivedClass(argument);
+   }
+
+   __global__ void destroy_on_device(MyBaseClass* myBaseClass) {
+      delete myBaseClass;
+   }
+
+   __global__ void callVirtualFunction(MyBaseClass* myBaseClass) {
+      myBaseClass->getValue();
+   }
+
+   int main(int argc, char** argv) {
+      MyBaseClass** d_temp;
+      cudaMalloc(&d_temp, sizeof(MyBaseClass*));
+      make_on_device<<<1, 1>>>(d_temp, 0);
+
+      MyBaseClass** temp = (MyBaseClass**) malloc(sizeof(MyBaseClass*));
+      cudaMemcpy(temp, d_temp, sizeof(MyBaseClass*), cudaMemcpyDeviceToHost);
+      MyBaseClass d_myBaseClass = *temp;
+
+      callVirtualFunction<<<1, 1>>>(d_myBaseClass);
+
+      free(temp);
+      destroy_on_device<<<1, 1>>>(d_myBaseClass);
+      cudaFree(d_temp);
+
+      return 0;
+   }
+
+OK, this is finally correct, but super tedious. So we took care of all the boilerplate and underlying details for you. The final result is at least recognizable when compared to the original code. The added benefit is that you can use a `chai::managed_ptr` on the host AND the device.
+
+.. code-block:: cpp
+
+   __global__ void callVirtualFunction(chai::managed_ptr<MyBaseClass> myBaseClass) {
+      myBaseClass->getValue();
+   }
+
+   int main(int argc, char** argv) {
+      chai::managed_ptr<MyBaseClass> myBaseClass = chai::make_managed<MyDerivedClass>(0);
+      myBaseClass->getValue(); // Accessible on the host
+      callVirtualFunction<<<1, 1>>>(myBaseClass); // Accessible on the device
+      myBaseClass.free();
+      return 0;
+   }
+
+OK, so we didn't do all the work for you, but we definitely gave you a leg up. What's left for you to do? You just need to make sure the functions accessed on the device have the `__device__` specifier (including constructors and destructors). We use the `CHAI_HOST_DEVICE` macro in this example, which actually annotates the functions as `__host__ __device__` so we can call the virtual method on both the host and the device. You also need to make sure the destructors of all base classes are virtual so the object gets cleaned up properly on the device.
+
+.. code-block:: cpp
+
+   class MyBaseClass {
+      public:
+         CARE_HOST_DEVICE MyBaseClass() {}
+         CARE_HOST_DEVICE virtual ~MyBaseClass() {}
+         CARE_HOST_DEVICE virtual int getValue() const = 0;
+   };
+
+   class MyDerivedClass : public MyBaseClass {
+      public:
+         CARE_HOST_DEVICE MyDerivedClass(int value) : MyBaseClass(), m_value(value) {}
+         CARE_HOST_DEVICE ~MyDerivedClass() {}
+         CARE_HOST_DEVICE int getValue() const { return m_value; }
+
+      private:
+         int m_value;
+   };
+
+Now you may rightfully ask, what happens when this class contains raw pointers? There is a convenient solution for this case and we demonstrate with a more interesting example.
+
+.. code-block:: cpp
+
+   class MyBaseClass {
+      public:
+         CARE_HOST_DEVICE MyBaseClass() {}
+         CARE_HOST_DEVICE virtual ~MyBaseClass() {}
+         CARE_HOST_DEVICE virtual int getScalarValue() const = 0;
+         CARE_HOST_DEVICE virtual int getArrayValue(int index) const = 0;
+   };
+
+   class MyDerivedClass : public MyBaseClass {
+      public:
+         CARE_HOST_DEVICE MyDerivedClass(int scalarValue, int* arrayValue)
+            : MyBaseClass(), m_scalarValue(scalarValue), m_arrayValue(arrayValue) {}
+         CARE_HOST_DEVICE ~MyDerivedClass() {}
+         CARE_HOST_DEVICE int getScalarValue() const { return m_scalarValue; }
+         CARE_HOST_DEVICE int getArrayValue() const { return m_arrayValue; }
+
+      private:
+         int m_scalarValue;
+         int* m_arrayValue;
+   };
+
+   __global__ void callVirtualFunction(chai::managed_ptr<MyBaseClass> myBaseClass) {
+      int i = blockIdx.x*blockDim.x + threadIdx.x;
+      myBaseClass->getScalarValue();
+      myBaseClass->getArrayValue(i);
+   }
+
+   int main(int argc, char** argv) {
+      chai::ManagedArray<int> arrayValue(10);
+      chai::managed_ptr<MyBaseClass> myBaseClass
+         = chai::make_managed<MyDerivedClass>(0, chai::unpack(arrayValue));
+      callVirtualFunction<<<1, 10>>>(myBaseClass);
+      myBaseClass.free();
+      arrayValue.free();
+      return 0;
+   }
+
+The respective host and device pointers contained in the `chai::ManagedArray` can be extracted and passed to the host and device instance of `MyDerivedClass` using `chai::unpack`. Of course, if you never dereference `m_arrayValue` on the device, you could simply pass a raw pointer to `chai::make_managed`. If the class contains a `chai::ManagedArray`, a `chai::ManagedArray` can simply be passed to the constructor. The same rules apply for passing a `chai::managed_ptr`, calling `chai::unpack` on a `chai::managed_ptr`, or passing a raw pointer and not accessing it on the device.
+
+More complicated rules apply for keeping the data in sync between the host and device instances of an object, but it is possible to do so to a limited extent. It is also possible to control the lifetimes of objects passed to `chai::make_managed`.
+
+.. code-block:: cpp
+   int main(int argc, char** argv) {
+      chai::ManagedArray<int> arrayValue(10);
+
+      chai::managed_ptr<MyBaseClass> myBaseClass
+         = chai::make_managed<MyDerivedClass>(0, chai::unpack(arrayValue));
+      myBaseClass.set_callback([=] (chai::Action action, chai::ExecutionSpace space, void*) mutable {
+         if (action == chai::ACTION_MOVE) {
+            (void) chai::ManagedArray<int> temp(arrayValue); // Copy constructor triggers movement
+         }
+         else if (action == chai::ACTION_FREE && space == chai::NONE) {
+            temp.free();
+         }
+
+         return false;
+      });
+
+      callVirtualFunction<<<1, 10>>>(myBaseClass);
+      myBaseClass.free();
+      // arrayValue.free(); // Not needed anymore
+      return 0;
+   }

scripts/make_release_tarball.sh

@@ -7,13 +7,13 @@
 ##############################################################################
 
 TAR_CMD=gtar
-VERSION=2.2.1
+VERSION=2.2.2
 
 git archive --prefix=chai-${VERSION}/ -o chai-${VERSION}.tar HEAD 2> /dev/null
 
 echo "Running git archive submodules..."
 
-p=`pwd` && (echo .; git submodule foreach) | while read entering path; do
+p=`pwd` && (echo .; git submodule foreach --recursive) | while read entering path; do
     temp="${path%\'}";
     temp="${temp#\'}";
     path=$temp;

src/chai/ArrayManager.cpp

@@ -445,8 +445,11 @@ PointerRecord* ArrayManager::deepCopyRecord(PointerRecord const* record)
   copy->m_user_callback = [] (const PointerRecord*, Action, ExecutionSpace) {};
 
   const ExecutionSpace last_space = record->m_last_space;
-
   copy->m_last_space = last_space;
+  for (int space = CPU; space < NUM_EXECUTION_SPACES; ++space) {
+    copy->m_allocators[space] = record->m_allocators[space];
+  }
+
   allocate(copy, last_space);
 
   for (int space = CPU; space < NUM_EXECUTION_SPACES; ++space) {

src/chai/ArrayManager.hpp

@@ -75,6 +75,8 @@ inline void synchronize() {
 #endif
 }
 
+#if defined(CHAI_GPUCC)
+
 // wrapper for hip/cuda free
 CHAI_HOST inline void gpuFree(void* buffer) {
 #if defined (CHAI_ENABLE_HIP)
@@ -111,6 +113,8 @@ CHAI_HOST inline void  gpuMemcpy(void* dst, const void* src, size_t count, gpuMe
 #endif
 }
 
+#endif //#if defined(CHAI_GPUCC)
+
 /*!
  * \brief Singleton that manages caching and movement of ManagedArray objects.
  *

src/chai/ManagedArray.hpp

@@ -173,7 +173,8 @@ class ManagedArray : public CHAICopyable
    */
   CHAI_HOST void registerTouch(ExecutionSpace space);
 
-  CHAI_HOST void move(ExecutionSpace space=NONE) const;
+  CHAI_HOST void move(ExecutionSpace space=NONE,
+                      bool registerTouch=!std::is_const<T>::value) const;
 
   CHAI_HOST_DEVICE ManagedArray<T> slice(size_t begin, size_t elems=(size_t)-1) const;
 
@@ -207,6 +208,15 @@ class ManagedArray : public CHAICopyable
    */
   CHAI_HOST_DEVICE T* data() const;
 
+  /*!
+   * \brief Move data to the current execution space (actually determined
+   *        by where the code is executing) and return a raw pointer. Do
+   *        not mark data as touched since a pointer to const is returned.
+   *
+   * \return Raw pointer to data in the current execution space
+   */
+  CHAI_HOST_DEVICE const T* cdata() const;
+
   /*!
    * \brief Return the raw pointer to the data in the given execution
    *        space. Optionally move the data to that execution space.