src/Pure/General/timing.ML

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/src/Pure/General/timing.ML	Sat Nov 06 17:55:32 2010 +0100
@@ -0,0 +1,36 @@
+(*  Title:      Pure/General/timing.ML
+    Author:     Makarius
+
+Basic support for time measurement.
+*)
+
+val seconds = Time.fromReal;
+
+fun start_timing () =
+  let
+    val real_timer = Timer.startRealTimer ();
+    val real_time = Timer.checkRealTimer real_timer;
+    val cpu_timer = Timer.startCPUTimer ();
+    val cpu_times = Timer.checkCPUTimes cpu_timer;
+  in (real_timer, real_time, cpu_timer, cpu_times) end;
+
+type timing = {message: string, elapsed: Time.time, cpu: Time.time, gc: Time.time};
+
+fun end_timing (real_timer, real_time, cpu_timer, cpu_times) : timing =
+  let
+    val real_time2 = Timer.checkRealTimer real_timer;
+    val {nongc = {sys, usr}, gc = {sys = gc_sys, usr = gc_usr}} = cpu_times;
+    val {nongc = {sys = sys2, usr = usr2}, gc = {sys = gc_sys2, usr = gc_usr2}} =
+      Timer.checkCPUTimes cpu_timer;
+
+    open Time;
+    val elapsed = real_time2 - real_time;
+    val gc = gc_usr2 - gc_usr + gc_sys2 - gc_sys;
+    val cpu = usr2 - usr + sys2 - sys + gc;
+
+    val message =
+     (toString elapsed ^ "s elapsed time, " ^
+      toString cpu ^ "s cpu time, " ^
+      toString gc ^ "s GC time") handle Time.Time => "";
+  in {message = message, elapsed = elapsed, cpu = cpu, gc = gc} end;
+