diff --git a/src/lib/stats/stats_mgr.cc b/src/lib/stats/stats_mgr.cc
index 20fbf9e640..30352b9819 100644
--- a/src/lib/stats/stats_mgr.cc
+++ b/src/lib/stats/stats_mgr.cc
@@ -35,48 +35,92 @@ StatsMgr::StatsMgr() :
 
 void
 StatsMgr::setValue(const string& name, const int64_t value) {
-    MultiThreadingMgr::call(*mutex_, [&]() {setValueInternal(name, value);});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        setValueInternal(name, value);
+    } else {
+        setValueInternal(name, value);
+    }
 }
 
 void
 StatsMgr::setValue(const string& name, const double value) {
-    MultiThreadingMgr::call(*mutex_, [&]() {setValueInternal(name, value);});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        setValueInternal(name, value);
+    } else {
+        setValueInternal(name, value);
+    }
 }
 
 void
 StatsMgr::setValue(const string& name, const StatsDuration& value) {
-    MultiThreadingMgr::call(*mutex_, [&]() {setValueInternal(name, value);});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        setValueInternal(name, value);
+    } else {
+        setValueInternal(name, value);
+    }
 }
 
 void
 StatsMgr::setValue(const string& name, const string& value) {
-    MultiThreadingMgr::call(*mutex_, [&]() {setValueInternal(name, value);});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        setValueInternal(name, value);
+    } else {
+        setValueInternal(name, value);
+    }
 }
 
 void
 StatsMgr::addValue(const string& name, const int64_t value) {
-    MultiThreadingMgr::call(*mutex_, [&]() {addValueInternal(name, value);});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        addValueInternal(name, value);
+    } else {
+        addValueInternal(name, value);
+    }
 }
 
 void
 StatsMgr::addValue(const string& name, const double value) {
-    MultiThreadingMgr::call(*mutex_, [&]() {addValueInternal(name, value);});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        addValueInternal(name, value);
+    } else {
+        addValueInternal(name, value);
+    }
 }
 
 void
 StatsMgr::addValue(const string& name, const StatsDuration& value) {
-    MultiThreadingMgr::call(*mutex_, [&]() {addValueInternal(name, value);});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        addValueInternal(name, value);
+    } else {
+        addValueInternal(name, value);
+    }
 }
 
 void
 StatsMgr::addValue(const string& name, const string& value) {
-    MultiThreadingMgr::call(*mutex_, [&]() {addValueInternal(name, value);});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        addValueInternal(name, value);
+    } else {
+        addValueInternal(name, value);
+    }
 }
 
 ObservationPtr
 StatsMgr::getObservation(const string& name) const {
-    return (MultiThreadingMgr::call(*mutex_,
-        [&]() {return getObservationInternal(name);}));
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        return (getObservationInternal(name));
+    } else {
+        return (getObservationInternal(name));
+    }
 }
 
 ObservationPtr
@@ -88,7 +132,12 @@ StatsMgr::getObservationInternal(const string& name) const {
 
 void
 StatsMgr::addObservation(const ObservationPtr& stat) {
-    MultiThreadingMgr::call(*mutex_, [&]() {addObservationInternal(stat);});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        addObservationInternal(stat);
+    } else {
+        addObservationInternal(stat);
+    }
 }
 
 void
@@ -100,8 +149,12 @@ StatsMgr::addObservationInternal(const ObservationPtr& stat) {
 
 bool
 StatsMgr::deleteObservation(const string& name) {
-    return (MultiThreadingMgr::call(*mutex_,
-        [&]() {return deleteObservationInternal(name);}));
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        return (deleteObservationInternal(name));
+    } else {
+        return (deleteObservationInternal(name));
+    }
 }
 
 bool
@@ -113,8 +166,12 @@ StatsMgr::deleteObservationInternal(const string& name) {
 
 bool
 StatsMgr::setMaxSampleAge(const string& name, const StatsDuration& duration) {
-    return (MultiThreadingMgr::call(*mutex_,
-        [&]() {return setMaxSampleAgeInternal(name, duration);}));
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        return (setMaxSampleAgeInternal(name, duration));
+    } else {
+        return (setMaxSampleAgeInternal(name, duration));
+    }
 }
 
 bool
@@ -130,8 +187,12 @@ StatsMgr::setMaxSampleAgeInternal(const string& name,
 
 bool
 StatsMgr::setMaxSampleCount(const string& name, uint32_t max_samples) {
-    return (MultiThreadingMgr::call(*mutex_,
-        [&]() {return setMaxSampleCountInternal(name, max_samples);}));
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        return (setMaxSampleCountInternal(name, max_samples));
+    } else {
+        return (setMaxSampleCountInternal(name, max_samples));
+    }
 }
 
 bool
@@ -147,7 +208,12 @@ StatsMgr::setMaxSampleCountInternal(const string& name,
 
 void
 StatsMgr::setMaxSampleAgeAll(const StatsDuration& duration) {
-    MultiThreadingMgr::call(*mutex_, [&]() {setMaxSampleAgeAllInternal(duration);});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        setMaxSampleAgeAllInternal(duration);
+    } else {
+        setMaxSampleAgeAllInternal(duration);
+    }
 }
 
 void
@@ -157,7 +223,12 @@ StatsMgr::setMaxSampleAgeAllInternal(const StatsDuration& duration) {
 
 void
 StatsMgr::setMaxSampleCountAll(uint32_t max_samples) {
-    MultiThreadingMgr::call(*mutex_, [&]() {setMaxSampleCountAllInternal(max_samples);});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        setMaxSampleCountAllInternal(max_samples);
+    } else {
+        setMaxSampleCountAllInternal(max_samples);
+    }
 }
 
 void
@@ -167,7 +238,12 @@ StatsMgr::setMaxSampleCountAllInternal(uint32_t max_samples) {
 
 bool
 StatsMgr::reset(const string& name) {
-    return MultiThreadingMgr::call(*mutex_, [&]() {return resetInternal(name);});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        return (resetInternal(name));
+    } else {
+        return (resetInternal(name));
+    }
 }
 
 bool
@@ -182,7 +258,12 @@ StatsMgr::resetInternal(const string& name) {
 
 bool
 StatsMgr::del(const string& name) {
-    return (MultiThreadingMgr::call(*mutex_, [&]() {return delInternal(name);}));
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        return (delInternal(name));
+    } else {
+        return (delInternal(name));
+    }
 }
 
 bool
@@ -192,7 +273,12 @@ StatsMgr::delInternal(const string& name) {
 
 void
 StatsMgr::removeAll() {
-    MultiThreadingMgr::call(*mutex_, [&]() {removeAllInternal();});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        removeAllInternal();
+    } else {
+        removeAllInternal();
+    }
 }
 
 void
@@ -202,7 +288,12 @@ StatsMgr::removeAllInternal() {
 
 ConstElementPtr
 StatsMgr::get(const string& name) const {
-    return (MultiThreadingMgr::call(*mutex_, [&]() {return getInternal(name);}));
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        return (getInternal(name));
+    } else {
+        return (getInternal(name));
+    }
 }
 
 ConstElementPtr
@@ -217,7 +308,12 @@ StatsMgr::getInternal(const string& name) const {
 
 ConstElementPtr
 StatsMgr::getAll() const {
-    return (MultiThreadingMgr::call(*mutex_, [&]() {return getAllInternal();}));
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        return (getAllInternal());
+    } else {
+        return (getAllInternal());
+    }
 }
 
 ConstElementPtr
@@ -227,7 +323,12 @@ StatsMgr::getAllInternal() const {
 
 void
 StatsMgr::resetAll() {
-    MultiThreadingMgr::call(*mutex_, [&]() {resetAllInternal();});
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        resetAllInternal();
+    } else {
+        resetAllInternal();
+    }
 }
 
 void
@@ -237,7 +338,12 @@ StatsMgr::resetAllInternal() {
 
 size_t
 StatsMgr::getSize(const string& name) const {
-    return (MultiThreadingMgr::call(*mutex_, [&]() {return getSizeInternal(name);}));
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        return (getSizeInternal(name));
+    } else {
+        return (getSizeInternal(name));
+    }
 }
 
 size_t
@@ -251,7 +357,12 @@ StatsMgr::getSizeInternal(const string& name) const {
 
 size_t
 StatsMgr::count() const {
-    return (MultiThreadingMgr::call(*mutex_, [&]() {return countInternal();}));
+    if (MultiThreadingMgr::instance().getMode()) {
+        lock_guard<mutex> lock(*mutex_);
+        return (countInternal());
+    } else {
+        return (countInternal());
+    }
 }
 
 size_t
diff --git a/src/lib/stats/stats_mgr.h b/src/lib/stats/stats_mgr.h
index 6ce58820b7..1ad598b5ab 100644
--- a/src/lib/stats/stats_mgr.h
+++ b/src/lib/stats/stats_mgr.h
@@ -719,14 +719,14 @@ private:
                                   uint32_t& max_samples,
                                   std::string& reason);
 
-    // This is a global context. All statistics will initially be stored here.
+    /// @brief This is a global context. All statistics will initially be stored here.
     StatContextPtr global_;
 
-    /// @brief Mutex used to protect internal state
+    /// @brief The mutex used to protect internal state.
     const boost::scoped_ptr<std::mutex> mutex_;
 };
 
-};
-};
+}  // namespace stats
+}  // namespace isc
 
 #endif // STATS_MGR
diff --git a/src/lib/util/multi_threading_mgr.h b/src/lib/util/multi_threading_mgr.h
index 1b2f768110..abaa7ae667 100644
--- a/src/lib/util/multi_threading_mgr.h
+++ b/src/lib/util/multi_threading_mgr.h
@@ -8,7 +8,6 @@
 #define MULTI_THREADING_MGR_H
 
 #include <boost/noncopyable.hpp>
-#include <mutex>
 
 namespace isc {
 namespace util {
@@ -29,14 +28,18 @@ namespace util {
 /// For instance for a class protected by its mutex:
 /// @code
 /// namespace locked {
-///     int foo() { ... }
+///     void foo() { ... }
 /// } // end of locked namespace
 ///
-/// int foo() {
-///     return MultiThreadingMgr::call(mutex_, []() {return locked::foo()});
+/// void foo() {
+///     if (MultiThreadingMgr::instance().getMode()) {
+///         lock_guard<mutex> lock(mutex_);
+///         locked::foo();
+///     } else {
+///         locked::foo();
+///     }
 /// }
 /// @endcode
-
 class MultiThreadingMgr : public boost::noncopyable {
 public:
 
@@ -59,23 +62,6 @@ public:
     /// @param enabled The new mode.
     void setMode(bool enabled);
 
-    /// @brief Call a Functor in MT or ST mode
-    ///
-    /// @tparam Lockable a lock which is used to create a thread safe context
-    /// @tparam Callable a functor which will be called in MT or ST mode
-    /// @param lk the lock object to perform lock in MT mode
-    /// @param f the functor to call
-    /// @result the result of the functor call
-    template<typename Lockable, typename Callable>
-    static auto call(Lockable& lk, const Callable& f) -> decltype(f()) {
-        if (MultiThreadingMgr::instance().getMode()) {
-            std::lock_guard<Lockable> lock(lk);
-            return f();
-        } else {
-            return f();
-        }
-    }
-
 protected:
 
     /// @brief Constructor.