diff --git a/build/gcc/makefile b/build/gcc/makefile
index 1caacce0..b61603ca 100644
--- a/build/gcc/makefile
+++ b/build/gcc/makefile
@@ -9,7 +9,7 @@ OBJS_DEBUG = $(patsubst %.cpp,debug/%.o,$(_SOURCES))
 
 CXX	= g++
 CXXFLAGS	= -march=native -Wall -Wextra -Wshadow -pedantic -std=c++11 -pthread -I../../include 
-CXX_RELEASE_FLAGS = -O2 -flto -g
+CXX_RELEASE_FLAGS = -O3 -flto 
 CXX_DEBUG_FLAGS= -g 
 
 OUTLIB_RELEASE = libc11log.a
diff --git a/include/c11log/formatters/formatters.h b/include/c11log/formatters/formatters.h
index 6ad3ccff..a6561ec5 100644
--- a/include/c11log/formatters/formatters.h
+++ b/include/c11log/formatters/formatters.h
@@ -13,8 +13,8 @@ namespace formatters {
 typedef std::chrono::system_clock clock;
 typedef clock::time_point time_point;
 typedef std::function<std::string(const std::string& logger_name, const std::string&, level::level_enum, const time_point&)> format_fn;
-void format_time(const time_point& tp, std::ostream &dest);
-void format_time(std::ostream &dest);
+
+
 std::string to_hex(const unsigned char* buf, std::size_t size);
 
 class formatter {
@@ -30,9 +30,11 @@ public:
     // Format: [2013-12-29 01:04:42.900] [logger_name:Info] Message body
     void format_header(const std::string& logger_name, level::level_enum level, const time_point& tp, std::ostream& dest) override
     {
-        format_time(tp, dest);
+        _format_time(tp, dest);
         dest << " [" <<  logger_name << ":" << c11log::level::to_str(level) << "] ";
     }
+private:
+	void _format_time(const time_point& tp, std::ostream &dest);
 
 };
 } //namespace formatter
diff --git a/src/formatters.cpp b/src/formatters.cpp
index a3ebf081..40365a2b 100644
--- a/src/formatters.cpp
+++ b/src/formatters.cpp
@@ -4,18 +4,15 @@
 #include "c11log/formatters/formatters.h"
 #include "c11log/level.h"
 
+thread_local c11log::formatters::time_point last_tp;
+thread_local char timestamp_cache[64];
 
-
-
-static thread_local c11log::formatters::time_point last_tp;
-static thread_local char timestamp_cache[64];
-
-void c11log::formatters::format_time(const time_point& tp, std::ostream &dest)
+void c11log::formatters::default_formatter::_format_time(const time_point& tp, std::ostream &dest)
 {
 
     // Cache timestamp string of last second
     using namespace std::chrono;
-	if(duration_cast<seconds>(tp-last_tp).count() >= 1)
+	if(duration_cast<milliseconds>(tp-last_tp).count() >= 950)
     {
     	auto tm = details::os::localtime(clock::to_time_t(tp));
 		sprintf(timestamp_cache, "[%d-%02d-%02d %02d:%02d:%02d]", tm.tm_year + 1900,
@@ -26,15 +23,9 @@ void c11log::formatters::format_time(const time_point& tp, std::ostream &dest)
 			tm.tm_sec);
 		last_tp = tp;
     }
-
 	dest << timestamp_cache;		
 }
 
-void c11log::formatters::format_time(std::ostream& dest)
-{
-    return format_time(c11log::formatters::clock::now(), dest);
-}
-
 
 static const char _hex_chars[17] = "0123456789ABCDEF";
 
diff --git a/src/test.cpp b/src/test.cpp
index 4fa7bb30..a09a6ecf 100644
--- a/src/test.cpp
+++ b/src/test.cpp
@@ -84,10 +84,10 @@ int main(int argc, char* argv[])
     auto null_sink = std::make_shared<c11log::sinks::null_sink>();
     auto stdout_sink = std::make_shared<c11log::sinks::stdout_sink>();
     auto async = std::make_shared<c11log::sinks::async_sink>(1000);
-    auto fsink = std::make_shared<c11log::sinks::rotating_file_sink>("newlog", "txt", 1024*1024*10 , 2);
+    auto fsink = std::make_shared<c11log::sinks::rotating_file_sink>("newlog", "txt", 1024*1024*50 , 5);
     //auto fsink = std::make_shared<c11log::sinks::daily_file_sink>("daily", "txt");
 
-	async->add_sink(null_sink);
+	async->add_sink(fsink);
 	auto &logger = c11log::get_logger("async");
 	logger.add_sink(async);