Add a new timer based on the direct ASM access,

from http://dept-info.labri.fr/~denis/Enseignement/2006-SSECPD/timing.h

git-svn-id: svn+ssh://scm.gforge.inria.fr/svn/scalfmm/scalfmm/trunk@313 2616d619-271b-44dc-8df4-d4a8f33a7222

Src/Utils/FTic.cpp

+#include "FTic.hpp"
+
+// The fallowing code is only needed when using the special timer
+#ifdef FSPECIAL_TIMER
+// This function is used to get the scale between tick and second
+double GetTickScale() {
+        typedef union u_tick {
+          uint64_t tick;
+          struct {
+            uint32_t low;
+            uint32_t high;
+          } sub;
+        } tick_t;
+
+        tick_t tickCounterStart, tickCounterEnd;
+        timeval todStart, todEnd;
+
+        __asm__ volatile("rdtsc" : "=a" (tickCounterStart.sub.low), "=d" (tickCounterStart.sub.high));
+        gettimeofday(&todStart,0);
+        usleep(500000);
+        __asm__ volatile("rdtsc" : "=a" (tickCounterEnd.sub.low), "=d" (tickCounterEnd.sub.high));
+        gettimeofday(&todEnd,0);
+        return ( (double(todEnd.tv_sec) + (double(todEnd.tv_usec)/1e6)) - (double(todStart.tv_sec) + (double(todStart.tv_usec)/1e6)) ) /
+                          double(tickCounterEnd.tick - tickCounterStart.tick);
+}
+// For the special timer
+const double FTic::Scale = GetTickScale();
+#endif

Src/Utils/FTic.hpp

 #ifndef FTIC_HPP
 #define FTIC_HPP
 
-#include <time.h>
-
 #include "FGlobal.hpp"
+#include <time.h>
 
 // We need an os specific function
 #if defined(WINDOWS)
@@ -12,14 +11,18 @@
     #ifndef POSIX
         #warning Posix used withoug being explicitly defined
     #endif
+    #if defined(__i386__) || defined(__pentium__) || defined(__pentiumpro__) || defined(__i586__) || defined(__i686__) || defined(__k6__) || defined(__k7__) || defined(__x86_64__)
+        #define FSPECIAL_TIMER
+    #endif
     #include <sys/time.h>
+    #include <unistd.h>
+    #include <stdint.h>
 #endif
 
 
 /** @author Berenger Bramas (berenger.bramas@inria.fr)
   * This class is a easy to use time counter
-  * With it you can very easyli estimate elapsed
-  * time between two moments
+  * With it you can very easyli estimate elapsed time between two moments
   * <code>
   * FTic counter;<br>
   * counter.tic();<br>
@@ -27,6 +30,9 @@
   * counter.tac();<br>
   * counter.elapsed(); //> time in s<br>
   * </code>
+  *
+  * The special method that uses asm register is based on the code by : Alexandre DENIS
+  * http://dept-info.labri.fr/~denis/Enseignement/2006-SSECPD/timing.h
   */
 class FTic {
 private:
@@ -73,17 +79,35 @@ public:
     /** Global get time
       * @return a global time
       * GetTickCount on windows
-      * gettimeofday on linux
+      * gettimeofday on linux or a direct ASM method
       */
     static double GetTime(){
 #ifdef WINDOWS
         return static_cast<double>(GetTickCount())/1000.0;
-#else
+#else // We are in linux/posix
+#ifndef FSPECIAL_TIMER
         timeval t;
         gettimeofday(&t, NULL);
         return double(t.tv_sec) + (double(t.tv_usec)/1000000.0);
+#else //FSPECIAL_TIMER is defined
+        typedef union u_tick {
+          uint64_t tick;
+          struct {
+            uint32_t low;
+            uint32_t high;
+          } sub;
+        } tick_t;
+
+        tick_t counter;
+        __asm__ volatile("rdtsc" : "=a" (counter.sub.low), "=d" (counter.sub.high));
+        return double(counter.tick) * Scale;
+#endif
 #endif
     }
+
+#ifdef FSPECIAL_TIMER
+    static const double Scale;
+#endif
 };