Add automatic check AVX in CMake (#145)

* Add automatic check AVX in CMake
* Revise table format and some words in build docs

CMakeLists.txt

@@ -17,6 +17,7 @@ find_package(PythonInterp 2.7 REQUIRED)
 find_package(ZLIB REQUIRED)
 find_package(NumPy REQUIRED)
 find_package(Threads REQUIRED)
+find_package(AVX QUIET)
 find_package(Glog)
 find_package(Gflags QUIET)
 find_package(GTest)
@@ -28,7 +29,7 @@ find_program(M4_EXECUTABLE m4)
 option(WITH_DSO "Compile PaddlePaddle with dynamic linked libraries" ON)
 option(WITH_GPU "Compile PaddlePaddle with gpu" ${CUDA_FOUND})
 option(WITH_DOUBLE "Compile PaddlePaddle with double precision, otherwise use single precision" OFF)
-option(WITH_AVX "Compile PaddlePaddle with avx intrinsics" ON) # TODO(yuyang18): Check AVX is supported or not as default value
+option(WITH_AVX "Compile PaddlePaddle with avx intrinsics" ${AVX_FOUND})
 option(WITH_PYTHON "Compile PaddlePaddle with python interpreter" ON)
 option(WITH_STYLE_CHECK "Style Check for PaddlePaddle" ${PYTHONINTERP_FOUND})
 option(WITH_RDMA "Compile PaddlePaddle with rdma support" OFF)
@@ -101,8 +102,8 @@ if(NOT WITH_TIMER)
 endif(NOT WITH_TIMER)
 
 if(WITH_AVX)
-    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -mavx")
-    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -mavx")
+    set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} ${AVX_FLAGS}")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${AVX_FLAGS}")
 else(WITH_AVX)
     set(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -msse3")
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -msse3")

cmake/FindAVX.cmake

+# This file is use to check all support level of AVX on your machine
+# so that PaddlePaddle can unleash the vectorization power of muticore.
+
+INCLUDE(CheckCXXSourceRuns)
+
+SET(FIND_AVX_10)
+SET(FIND_AVX_20)
+SET(AVX_FLAGS)
+SET(AVX_FOUND)
+
+# Check AVX 2
+SET(CMAKE_REQUIRED_FLAGS)
+IF(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  SET(CMAKE_REQUIRED_FLAGS "-mavx2")
+ELSEIF(MSVC AND NOT CMAKE_CL_64)  # reserve for WINDOWS
+  SET(CMAKE_REQUIRED_FLAGS "/arch:AVX2")
+ENDIF()
+
+CHECK_CXX_SOURCE_RUNS("
+#include <immintrin.h>
+int main()
+{
+    __m256i a = _mm256_set_epi32 (-1, 2, -3, 4, -1, 2, -3, 4);
+    __m256i result = _mm256_abs_epi32 (a);
+    return 0;
+}" FIND_AVX_20)
+
+# Check AVX
+SET(CMAKE_REQUIRED_FLAGS)
+IF(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    SET(CMAKE_REQUIRED_FLAGS "-mavx")
+ELSEIF(MSVC AND NOT CMAKE_CL_64)
+    SET(CMAKE_REQUIRED_FLAGS "/arch:AVX")
+endif()
+
+CHECK_CXX_SOURCE_RUNS("
+#include <immintrin.h>
+int main()
+{
+    __m256 a = _mm256_set_ps (-1.0f, 2.0f, -3.0f, 4.0f, -1.0f, 2.0f, -3.0f, 4.0f);
+    __m256 b = _mm256_set_ps (1.0f, 2.0f, 3.0f, 4.0f, 1.0f, 2.0f, 3.0f, 4.0f);
+    __m256 result = _mm256_add_ps (a, b);
+    return 0;
+}" FIND_AVX_10)
+
+IF(${FIND_AVX_20})
+    IF(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+        SET(AVX_FLAGS "${AVX_FLAGS} -mavx2")
+    ELSEIF(MSVC)
+        SET(AVX_FLAGS "${AVX_FLAGS} /arch:AVX2")
+    ENDIF()
+ENDIF()
+
+IF(${FIND_AVX_10})
+    IF(CMAKE_COMPILER_IS_GNUCC OR CMAKE_COMPILER_IS_GNUCXX OR CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+        SET(AVX_FLAGS "${AVX_FLAGS} -mavx")
+    ELSEIF(MSVC)
+        SET(AVX_FLAGS "${AVX_FLAGS} /arch:AVX")
+    ENDIF()
+ENDIF()
+
+IF(${FIND_AVX_10} OR ${FIND_AVX_20})
+    SET(AVX_FOUND TRUE)
+    MESSAGE(STATUS "Find CPU supports ${AVX_FLAGS}.")
+ENDIF()
\ No newline at end of file

doc/build/build_from_source.md

@@ -11,11 +11,12 @@ You can download PaddlePaddle from the [github source](https://github.com/gangli
 
 ```bash
 git clone https://github.com/baidu/Paddle paddle
+cd paddle
 ```
 
 ## <span id="requirements">Requirements</span>
 
-To compile the source code, your computer must be equipped with GCC >=4.6 or Clang Compiler.
+To compile the source code, your computer must be equipped with GCC >=4.6 or Clang compiler.
 ### Dependencies
 
 - **CMake**: version >= 2.8
@@ -27,17 +28,17 @@ To compile the source code, your computer must be equipped with GCC >=4.6 or Cla
 
 PaddlePaddle supports some build options. To enable it, first you need to install the related libraries. 
 
-    Optional            | Description
-    ------------        | :-----------
-    **WITH_GPU**        | Compile with GPU mode.
-    **WITH_DOUBLE**     | Compile with double precision floating-point, default: single precision. |
-    **WITH_GLOG**       | Compile with glog. If not found, default: an internal log implementation.
-    **WITH_GFLAGS**     | Compile with gflags. If not found, default: an internal flag implementation.
-    **WITH_TESTING**    | Compile with gtest for PaddlePaddle's unit testing. 
-    **WITH_DOC**        | Compile to generate PaddlePaddle's docs, default: disabled (OFF).
-    **WITH_SWIG_PY**    | Compile with python predict API, default: disabled (OFF).
-    **WITH_STYLE_CHECK**| Compile with code style check, default: enabled (ON).
-|
+
+| Optional             | Description                                                                  |
+| -------------------- | :--------------------------------------------------------------------------- |
+| **WITH_GPU**         | Compile with GPU mode.                                                       |
+| **WITH_DOUBLE**      | Compile with double precision floating-point, default: single precision.     |
+| **WITH_GLOG**        | Compile with glog. If not found, default: an internal log implementation.    |
+| **WITH_GFLAGS**      | Compile with gflags. If not found, default: an internal flag implementation. |
+| **WITH_TESTING**     | Compile with gtest for PaddlePaddle's unit testing.                          |
+| **WITH_DOC**         | Compile to generate PaddlePaddle's docs, default: disabled (OFF).            |
+| **WITH_SWIG_PY**     | Compile with python predict API, default: disabled (OFF).                    |
+| **WITH_STYLE_CHECK** | Compile with code style check, default: enabled (ON).                        |
 
 **Note:**
   - The GPU version works best with Cuda Toolkit 7.5 and cuDNN v5.
@@ -118,11 +119,10 @@ As a simple example, consider the following:
     sudo tar -xzf cudnn-7.5-linux-x64-v5.1.tgz -C /usr/local
     sudo chmod a+r /usr/local/cuda/include/cudnn.h /usr/local/cuda/lib64/libcudnn*
     ```
-    Then you need to set LD\_LIBRARY\_PATH, CUDA\_HOME and PATH environment variables in ~/.bashrc.
+    Then you need to set LD\_LIBRARY\_PATH, PATH environment variables in ~/.bashrc.
 
     ```bash
     export LD_LIBRARY_PATH=/usr/local/cuda/lib64:$LD_LIBRARY_PATH
-    export CUDA_HOME=/usr/local/cuda
     export PATH=/usr/local/cuda/bin:$PATH
     ```
 
@@ -158,13 +158,12 @@ As a simple example, consider the following:
   cmake .. -DWITH_GPU=ON -DWITH_DOC=ON -DWITH_SWIG_PY=ON
   ``` 
 
-Finally, you can download source code and build:
+Finally, you can build PaddlePaddle:
 
 ```bash
 # you can add build option here, such as:    
 cmake .. -DWITH_GPU=ON -DWITH_DOC=OFF -DCMAKE_INSTALL_PREFIX=<path to install>
-# please use sudo make install, if you want
-# to install PaddlePaddle into the system
+# please use sudo make install, if you want to install PaddlePaddle into the system
 make -j `nproc` && make install
 # set PaddlePaddle installation path in ~/.bashrc
 export PATH=<path to install>/bin:$PATH
@@ -240,7 +239,7 @@ easy_install pip
         sudo tar -xzf cudnn-7.5-osx-x64-v5.0-ga.tgz -C /usr/local
         sudo chmod a+r /usr/local/cuda/include/cudnn.h /usr/local/cuda/lib64/libcudnn*
         ```
-    2. Then you need to set DYLD\_LIBRARY\_PATH, CUDA\_HOME and PATH environment variables in ~/.bashrc.
+    2. Then you need to set DYLD\_LIBRARY\_PATH, PATH environment variables in ~/.bashrc.
 
         ```bash
         export DYLD_LIBRARY_PATH=/usr/local/cuda/lib:$DYLD_LIBRARY_PATH
@@ -289,8 +288,6 @@ make -j `nproc` && make install
 # set PaddlePaddle installation path in ~/.bashrc
 export PATH=<installation path>/bin:$PATH
 ```
-
-
 **Note:**
 
 If you set `WITH_SWIG_PY=ON`, related python dependencies also need to be installed.