Disable threads completely if OpenMP is not present.
This reduces the penalty paid by Mutex lock and unlock operations
in single threaded mode.
Change-Id: I185380bde73fe87e901fc434d152d6c366ff1d5d
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f5aaeed..537a103 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -43,7 +43,7 @@
# Git Bash (shipped with msysgit)
SET (LOCAL_GIT_DIRECTORY ${CMAKE_SOURCE_DIR}/.git)
ELSE (EXISTS ${CMAKE_SOURCE_DIR}/.git)
- # TODO(keir) Add proper windows support
+ # TODO(keir) Add proper Windows support
ENDIF (EXISTS ${CMAKE_SOURCE_DIR}/.git)
IF (EXISTS ${LOCAL_GIT_DIRECTORY})
@@ -471,15 +471,35 @@
IF (${OPENMP})
FIND_PACKAGE(OpenMP)
- IF(${OPENMP_FOUND})
- MESSAGE("-- Found OpenMP.")
- SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
- ADD_DEFINITIONS(-DCERES_USE_OPENMP)
- ELSE(${OPENMP_FOUND})
- MESSAGE("-- Can't find OpenMP. Continuing without it.")
- ENDIF(${OPENMP_FOUND})
ENDIF (${OPENMP})
+IF(${OPENMP_FOUND})
+ MESSAGE("-- Found OpenMP.")
+ ADD_DEFINITIONS(-DCERES_USE_OPENMP)
+ SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${OpenMP_CXX_FLAGS}")
+ IF ("${UNIX}")
+ # At least on Linux, we need pthreads to be enabled for mutex to
+ # compile. This may not work on Windows or Android.
+ FIND_PACKAGE(Threads REQUIRED)
+ SET(STATIC_LIBRARY_FLAGS
+ "${STATIC_LIBRARY_FLAGS} ${CMAKE_THREAD_LIBS_INIT}")
+ SET(CMAKE_SHARED_LINKER_FLAGS
+ "${CMAKE_SHARED_LINKER_FLAGS} ${CMAKE_THREAD_LIBS_INIT}")
+ ADD_DEFINITIONS(-DCERES_HAVE_PTHREAD)
+ ADD_DEFINITIONS(-DCERES_HAVE_RWLOCK)
+ ENDIF ("${UNIX}")
+ELSE(${OPENMP_FOUND})
+ MESSAGE("-- Can't find OpenMP. Disabling multithreading.")
+ ADD_DEFINITIONS(-DCERES_NO_THREADS)
+ENDIF(${OPENMP_FOUND})
+
+# Disable threads in mutex.h. Someday, after there is OpenMP support in
+# Android, this can get removed. Also turn on a workaround for an NDK bug.
+IF (${BUILD_ANDROID})
+ ADD_DEFINITIONS(-DCERES_NO_THREADS)
+ ADD_DEFINITIONS(-DCERES_WORK_AROUND_ANDROID_NDK_COMPILER_BUG)
+ENDIF (${BUILD_ANDROID})
+
# Protocol buffers
OPTION(PROTOBUF
"Enable protocol buffers support."
@@ -497,25 +517,6 @@
ADD_DEFINITIONS(-DCERES_NO_PROTOCOL_BUFFERS)
ENDIF (${PROTOBUF})
-
-# Use threads but not on Android, where there is no support for OpenMP yet.
-IF ("${UNIX}" AND NOT ${BUILD_ANDROID})
- # At least on Linux, we need pthreads to be enabled for mutex to compile.
- # This may not work on windows or android.
- FIND_PACKAGE(Threads REQUIRED)
- SET(STATIC_LIBRARY_FLAGS "${STATIC_LIBRARY_FLAGS} ${CMAKE_THREAD_LIBS_INIT}")
- SET(CMAKE_SHARED_LINKER_FLAGS "${CMAKE_SHARED_LINKER_FLAGS} ${CMAKE_THREAD_LIBS_INIT}")
- ADD_DEFINITIONS(-DCERES_HAVE_PTHREAD)
- ADD_DEFINITIONS(-DCERES_HAVE_RWLOCK)
-ENDIF ("${UNIX}" AND NOT ${BUILD_ANDROID})
-
-# Disable threads in mutex.h. Someday, after there is OpenMP support in
-# Android, this can get removed. Also turn on a workaround for an NDK bug.
-IF (${BUILD_ANDROID})
- ADD_DEFINITIONS(-DCERES_NO_THREADS)
- ADD_DEFINITIONS(-DCERES_WORK_AROUND_ANDROID_NDK_COMPILER_BUG)
-ENDIF (${BUILD_ANDROID})
-
OPTION(DISABLE_TR1
"Don't use TR1. This replaces some hash tables with sets. Slower."
OFF)
