Detect and use atomic integer operations for RefObject reference counter.

Note that GCC supports them on specific architectures, on some platforms -march=... must be set in CFLAGS.


git-svn-id: http://voip.null.ro/svn/yate@4682 acf43c95-373e-0410-b603-e72c3f656dc1

configure.in

@@ -291,6 +291,29 @@ esac
 AC_MSG_RESULT([$want_inline])
 AC_SUBST(INLINE_FLAGS)
 
+# Check for atomic integer operations
+ATOMIC_OPS=""
+AC_ARG_ENABLE(atomics,AC_HELP_STRING([--enable-atomics],[Enable atomic integer operations (default: yes)]),want_atomics=$enableval,want_atomics=yes)
+if [[ "x$want_atomics" != "xno" ]]; then
+AC_MSG_CHECKING([whether to use atomic integer operations])
+AC_LANG_SAVE
+AC_LANG_C
+SAVE_CFLAGS="$CFLAGS"
+CFLAGS="$CFLAGS -Wall -Werror"
+AC_TRY_LINK([],[
+int i = 0;
+int j = __sync_add_and_fetch(&i,1);
+return __sync_fetch_and_sub(&j,1);
+],
+ATOMIC_OPS="-DATOMIC_OPS",
+want_atomics="no (missing -march ?)"
+)
+CFLAGS="$SAVE_CFLAGS"
+AC_LANG_RESTORE
+AC_MSG_RESULT([$want_atomics])
+fi
+AC_SUBST(ATOMIC_OPS)
+
 FDSIZE_HACK=""
 AC_ARG_WITH(fdsize,AC_HELP_STRING([--with-fdsize=NNNN],[set FD_SIZE to NNNN (default 8192)]),[ac_cv_use_fdsize=$withval],[ac_cv_use_fdsize=8192])
 if [[ "x$ac_cv_use_fdsize" != "xno" ]]; then

engine/Makefile.in

@@ -100,6 +100,9 @@ Mutex.o: @srcdir@/Mutex.cpp $(MKDEPS) $(CINC)
 Thread.o: @srcdir@/Thread.cpp $(MKDEPS) $(CINC)
 	$(COMPILE) @THREAD_KILL@ @HAVE_PRCTL@ -c $<
 
+TelEngine.o: @srcdir@/TelEngine.cpp $(MKDEPS) $(CINC)
+	$(COMPILE) @ATOMIC_OPS@ -c $<
+
 Client.o: @srcdir@/Client.cpp $(MKDEPS) $(CLINC)
 	$(COMPILE) -c $<
 

engine/TelEngine.cpp

@@ -627,12 +627,16 @@ void GenObject::destruct()
 }
 
 
+#ifndef ATOMIC_OPS
 static MutexPool s_refMutex(REFOBJECT_MUTEX_COUNT,false,"RefObject");
+#endif
 
 RefObject::RefObject()
     : m_refcount(1), m_mutex(0)
 {
+#ifndef ATOMIC_OPS
     m_mutex = s_refMutex.mutex(this);
+#endif
 }
 
 RefObject::~RefObject()
@@ -653,21 +657,45 @@ void RefObject::destruct()
 
 bool RefObject::ref()
 {
+#ifdef ATOMIC_OPS
+#ifdef _WINDOWS
+    if (InterlockedIncrement((LONG*)&m_refcount) > 1)
+	return true;
+    InterlockedDecrement((LONG*)&m_refcount);
+#else
+    if (__sync_add_and_fetch(&m_refcount,1) > 1)
+	return true;
+    __sync_sub_and_fetch(&m_refcount,1);
+#endif
+#else
     Lock lock(m_mutex);
     if (m_refcount > 0) {
 	++m_refcount;
 	return true;
     }
+#endif
     return false;
 }
 
 bool RefObject::deref()
 {
+#ifdef ATOMIC_OPS
+#ifdef _WINDOWS
+    int i = InterlockedDecrement((LONG*)&m_refcount) + 1;
+    if (i <= 0)
+	InterlockedIncrement((LONG*)&m_refcount);
+#else
+    int i = __sync_fetch_and_sub(&m_refcount,1);
+    if (i <= 0)
+	__sync_fetch_and_add(&m_refcount,1);
+#endif
+#else
     m_mutex->lock();
     int i = m_refcount;
     if (i > 0)
 	--m_refcount;
     m_mutex->unlock();
+#endif
     if (i == 1)
 	zeroRefs();
     else if (i <= 0)
@@ -683,18 +711,40 @@ void RefObject::zeroRefs()
 
 bool RefObject::resurrect()
 {
+#ifdef ATOMIC_OPS
+#ifdef _WINDOWS
+    if (InterlockedIncrement((LONG*)&m_refcount) == 1)
+	return true;
+    InterlockedDecrement((LONG*)&m_refcount);
+    return false;
+#else
+    if (__sync_add_and_fetch(&m_refcount,1) == 1)
+	return true;
+    __sync_sub_and_fetch(&m_refcount,1);
+    return false;
+#endif
+#else
     m_mutex->lock();
     bool ret = (0 == m_refcount);
     if (ret)
 	m_refcount = 1;
     m_mutex->unlock();
     return ret;
+#endif
 }
 
 void RefObject::destroyed()
 {
 }
 
+bool RefObject::efficientIncDec()
+{
+#ifdef ATOMIC_OPS
+    return true;
+#else
+    return false;
+#endif
+}
 
 void RefPointerBase::assign(RefObject* oldptr, RefObject* newptr, void* pointer)
 {

windows/Libyate.vcproj

@@ -49,7 +49,7 @@
 				Name="VCCLCompilerTool"
 				Optimization="0"
 				AdditionalIncludeDirectories=".,..,..\engine\regex,..\engine\tables"
-				PreprocessorDefinitions="WIN32;_DEBUG;_WINDOWS;_USRDLL;LIBYATE_EXPORTS;__STDC__;_CRT_SECURE_NO_DEPRECATE;HAVE_DNS_NAPTR_DATA"
+				PreprocessorDefinitions="WIN32;_DEBUG;_WINDOWS;_USRDLL;LIBYATE_EXPORTS;__STDC__;_CRT_SECURE_NO_DEPRECATE;ATOMIC_OPS;HAVE_DNS_NAPTR_DATA"
 				MinimalRebuild="true"
 				BasicRuntimeChecks="3"
 				RuntimeLibrary="3"
@@ -147,7 +147,7 @@
 				Optimization="2"
 				InlineFunctionExpansion="1"
 				AdditionalIncludeDirectories=".,..,..\engine\regex,..\engine\tables"
-				PreprocessorDefinitions="WIN32;NDEBUG;_WINDOWS;_USRDLL;LIBYATE_EXPORTS;__STDC__;_CRT_SECURE_NO_DEPRECATE;HAVE_DNS_NAPTR_DATA"
+				PreprocessorDefinitions="WIN32;NDEBUG;_WINDOWS;_USRDLL;LIBYATE_EXPORTS;__STDC__;_CRT_SECURE_NO_DEPRECATE;ATOMIC_OPS;HAVE_DNS_NAPTR_DATA"
 				StringPooling="true"
 				RuntimeLibrary="2"
 				EnableFunctionLevelLinking="true"

yateclass.h

@@ -812,6 +812,13 @@ public:
      */
     virtual void destruct();
 
+    /**
+     * Check if reference counter manipulations are efficient on this platform.
+     * If platform does not support atomic operations a mutex pool is used.
+     * @return True if refcount uses atomic integer operations
+     */
+    static bool efficientIncDec();
+
 protected:
     /**
      * This method is called when the reference count reaches zero after