Change mert/Timer.

- Add a high resolution timing function to measure the
  wall-clock time by gettimeofday().

- Now the Timer class use getrusage() to measure the elapsed
  CPU time as KenLM does.

- Revive Timer::restart().

- Add Timer::ToString() for reporting the detail statistics
  as well as for debugging.

- Add a simple unit test for Timer.

1 files changed, 27 insertions, 0 deletions

diff --git a/mert/TimerTest.cpp b/mert/TimerTest.cpp
new file mode 100644
index 000000000..04ec75dfa
--- /dev/null
+++ b/mert/TimerTest.cpp
@@ -0,0 +1,27 @@
+#include "Timer.h"
+
+#define BOOST_TEST_MODULE TimerTest
+#include <boost/test/unit_test.hpp>
+
+#include <string>
+#include <iostream>
+
+BOOST_AUTO_TEST_CASE(timer_basic_test) {
+  Timer timer;
+  timer.start();
+  BOOST_REQUIRE(timer.is_running());
+  BOOST_REQUIRE(timer.get_elapsed_cpu_time() > 0.0);
+  BOOST_REQUIRE(timer.get_elapsed_cpu_time_microseconds() > 0);
+  BOOST_REQUIRE(timer.get_elapsed_wall_time() > 0.0);
+  BOOST_REQUIRE(timer.get_elapsed_wall_time_microseconds() > 0);
+
+  timer.restart();
+  BOOST_REQUIRE(timer.is_running());
+  BOOST_REQUIRE(timer.get_elapsed_cpu_time() > 0.0);
+  BOOST_REQUIRE(timer.get_elapsed_cpu_time_microseconds() > 0);
+  BOOST_REQUIRE(timer.get_elapsed_wall_time() > 0.0);
+  BOOST_REQUIRE(timer.get_elapsed_wall_time_microseconds() > 0);
+
+  const std::string s = timer.ToString();
+  BOOST_REQUIRE(!s.empty());
+}