X-Git-Url: http://git.lttng.org/?a=blobdiff_plain;f=ltt%2Fbranches%2Fpoly%2Fltt%2Ftime.h;h=7cb7c8bb95914f303fd484eb7af5e8ff7ce75d07;hb=49f3c39e02a4f8a60a3656c2cbdeec23ef8f58ca;hp=d904953099c96da1888fd1aa826966736eb91e84;hpb=0aa6c3a15541d012d2ab10034090490fc2a2d1ca;p=lttv.git

diff --git a/ltt/branches/poly/ltt/time.h b/ltt/branches/poly/ltt/time.h
index d9049530..7cb7c8bb 100644
--- a/ltt/branches/poly/ltt/time.h
+++ b/ltt/branches/poly/ltt/time.h
@@ -20,7 +20,7 @@
 #define LTT_TIME_H
 
 #include <glib.h>
-
+#include <ltt/compiler.h>
 
 typedef struct _LttTime {
   unsigned long tv_sec;
@@ -29,6 +29,7 @@ typedef struct _LttTime {
 
 
 #define NANOSECONDS_PER_SECOND 1000000000
+#define SHIFT_CONST 1.07374182400631629848
 
 static const LttTime ltt_time_zero = { 0, 0 };
 
@@ -40,12 +41,14 @@ static inline LttTime ltt_time_sub(LttTime t1, LttTime t2)
 {
   LttTime res;
   res.tv_sec  = t1.tv_sec  - t2.tv_sec;
-  if(t1.tv_nsec < t2.tv_nsec) {
+  res.tv_nsec = t1.tv_nsec - t2.tv_nsec;
+  /* unlikely : given equal chance to be anywhere in t1.tv_nsec, and
+   * higher probability of low value for t2.tv_sec, we will habitually
+   * not wrap.
+   */
+  if(unlikely(t1.tv_nsec < t2.tv_nsec)) {
     res.tv_sec--;
-    res.tv_nsec = NANOSECONDS_PER_SECOND + t1.tv_nsec - t2.tv_nsec;
-  }
-  else {
-    res.tv_nsec = t1.tv_nsec - t2.tv_nsec;
+    res.tv_nsec += NANOSECONDS_PER_SECOND;
   }
   return res;
 }
@@ -54,26 +57,98 @@ static inline LttTime ltt_time_sub(LttTime t1, LttTime t2)
 static inline LttTime ltt_time_add(LttTime t1, LttTime t2) 
 {
   LttTime res;
-  res.tv_sec  = t1.tv_sec  + t2.tv_sec;
   res.tv_nsec = t1.tv_nsec + t2.tv_nsec;
-  if(res.tv_nsec >= NANOSECONDS_PER_SECOND) {
+  res.tv_sec = t1.tv_sec + t2.tv_sec;
+  /* unlikely : given equal chance to be anywhere in t1.tv_nsec, and
+   * higher probability of low value for t2.tv_sec, we will habitually
+   * not wrap.
+   */
+  if(unlikely(res.tv_nsec >= NANOSECONDS_PER_SECOND)) {
     res.tv_sec++;
     res.tv_nsec -= NANOSECONDS_PER_SECOND;
   }
   return res;
 }
 
+/* Fastest comparison : t1 > t2 */
+static inline int ltt_time_compare(LttTime t1, LttTime t2)
+{
+  int ret=0;
+  if(likely(t1.tv_sec > t2.tv_sec)) ret = 1;
+  else if(unlikely(t1.tv_sec < t2.tv_sec)) ret = -1;
+  else if(likely(t1.tv_nsec > t2.tv_nsec)) ret = 1;
+  else if(unlikely(t1.tv_nsec < t2.tv_nsec)) ret = -1;
+  
+  return ret;
+}
+
+#define LTT_TIME_MIN(a,b) ((ltt_time_compare((a),(b)) < 0) ? (a) : (b))
+#define LTT_TIME_MAX(a,b) ((ltt_time_compare((a),(b)) > 0) ? (a) : (b))
+
+#define MAX_TV_SEC_TO_DOUBLE 0x7FFFFF
+static inline double ltt_time_to_double(LttTime t1)
+{
+  /* We lose precision if tv_sec is > than (2^23)-1
+   * 
+   * Max values that fits in a double (53 bits precision on normalised 
+   * mantissa):
+   * tv_nsec : NANOSECONDS_PER_SECONDS : 2^30
+   *
+   * So we have 53-30 = 23 bits left for tv_sec.
+   * */
+#ifdef EXTRA_CHECK
+  g_assert(t1.tv_sec <= MAX_TV_SEC_TO_DOUBLE);
+  if(t1.tv_sec > MAX_TV_SEC_TO_DOUBLE)
+    g_warning("Precision loss in conversion LttTime to double");
+#endif //EXTRA_CHECK
+  return ((double)t1.tv_sec * (double)NANOSECONDS_PER_SECOND) + (double)t1.tv_nsec;
+}
+
 
-static inline LttTime ltt_time_mul(LttTime t1, float f)
+static inline LttTime ltt_time_from_double(double t1)
 {
+  /* We lose precision if tv_sec is > than (2^23)-1
+   * 
+   * Max values that fits in a double (53 bits precision on normalised 
+   * mantissa):
+   * tv_nsec : NANOSECONDS_PER_SECONDS : 2^30
+   *
+   * So we have 53-30 = 23 bits left for tv_sec.
+   * */
+#ifdef EXTRA_CHECK
+  g_assert(t1 <= MAX_TV_SEC_TO_DOUBLE);
+  if(t1 > MAX_TV_SEC_TO_DOUBLE)
+    g_warning("Conversion from non precise double to LttTime");
+#endif //EXTRA_CHECK
   LttTime res;
-  float d;
-  double sec;
+  //res.tv_sec = t1/(double)NANOSECONDS_PER_SECOND;
+  res.tv_sec = (guint64)(t1 * SHIFT_CONST) >> 30;
+  res.tv_nsec = (t1 - (res.tv_sec*NANOSECONDS_PER_SECOND));
+  return res;
+}
+
+/* Use ltt_time_to_double and ltt_time_from_double to check for lack
+ * of precision.
+ */
+static inline LttTime ltt_time_mul(LttTime t1, double d)
+{
+  LttTime res;
+
+  double time_double = ltt_time_to_double(t1);
+
+  time_double = time_double * d;
 
+  res = ltt_time_from_double(time_double);
+
+  return res;
+
+#if 0
+  /* What is that ? (Mathieu) */
   if(f == 0.0){
     res.tv_sec = 0;
     res.tv_nsec = 0;
   }else{
+  double d;
     d = 1.0/f;
     sec = t1.tv_sec / (double)d;
     res.tv_sec = sec;
@@ -83,11 +158,27 @@ static inline LttTime ltt_time_mul(LttTime t1, float f)
     res.tv_nsec %= NANOSECONDS_PER_SECOND;
   }
   return res;
+#endif //0
 }
 
 
-static inline LttTime ltt_time_div(LttTime t1, float f)
+/* Use ltt_time_to_double and ltt_time_from_double to check for lack
+ * of precision.
+ */
+static inline LttTime ltt_time_div(LttTime t1, double d)
 {
+  LttTime res;
+
+  double time_double = ltt_time_to_double(t1);
+
+  time_double = time_double / d;
+
+  res = ltt_time_from_double(time_double);
+
+  return res;
+
+
+#if 0
   double sec;
   LttTime res;
 
@@ -98,55 +189,34 @@ static inline LttTime ltt_time_div(LttTime t1, float f)
   res.tv_sec += res.tv_nsec / NANOSECONDS_PER_SECOND;
   res.tv_nsec %= NANOSECONDS_PER_SECOND;
   return res;
+#endif //0
 }
 
-
-static inline int ltt_time_compare(LttTime t1, LttTime t2)
+static inline guint64 ltt_time_to_uint64(LttTime t1)
 {
-  if(t1.tv_sec > t2.tv_sec) return 1;
-  if(t1.tv_sec < t2.tv_sec) return -1;
-  if(t1.tv_nsec > t2.tv_nsec) return 1;
-  if(t1.tv_nsec < t2.tv_nsec) return -1;
-  return 0;
-}
-
-#define LTT_TIME_MIN(a,b) ((ltt_time_compare((a),(b)) < 0) ? (a) : (b))
-#define LTT_TIME_MAX(a,b) ((ltt_time_compare((a),(b)) > 0) ? (a) : (b))
-
-#define MAX_TV_SEC_TO_DOUBLE 0x7FFFFF
-static inline double ltt_time_to_double(LttTime t1)
-{
-  /* We lose precision if tv_sec is > than (2^23)-1
-   * 
-   * Max values that fits in a double (53 bits precision on normalised 
-   * mantissa):
-   * tv_nsec : NANOSECONDS_PER_SECONDS : 2^30
-   *
-   * So we have 53-30 = 23 bits left for tv_sec.
-   * */
-  g_assert(t1.tv_sec <= MAX_TV_SEC_TO_DOUBLE);
-  if(t1.tv_sec > MAX_TV_SEC_TO_DOUBLE)
-    g_warning("Precision loss in conversion LttTime to double");
-  return (double)t1.tv_sec + (double)t1.tv_nsec / NANOSECONDS_PER_SECOND;
+  return (guint64)t1.tv_sec*NANOSECONDS_PER_SECOND
+            + (guint64)t1.tv_nsec;
 }
 
 
-static inline LttTime ltt_time_from_double(double t1)
+#define MAX_TV_SEC_TO_UINT64 0x3FFFFFFFFFFFFFFFULL
+static inline LttTime ltt_time_from_uint64(guint64 t1)
 {
-  /* We lose precision if tv_sec is > than (2^23)-1
-   * 
-   * Max values that fits in a double (53 bits precision on normalised 
-   * mantissa):
-   * tv_nsec : NANOSECONDS_PER_SECONDS : 2^30
-   *
-   * So we have 53-30 = 23 bits left for tv_sec.
+  /* We lose precision if tv_sec is > than (2^62)-1
    * */
-  g_assert(t1 <= MAX_TV_SEC_TO_DOUBLE);
-  if(t1 > MAX_TV_SEC_TO_DOUBLE)
-    g_warning("Conversion from non precise double to LttTime");
+#ifdef EXTRA_CHECK
+  g_assert(t1 <= MAX_TV_SEC_TO_UINT64);
+  if(t1 > MAX_TV_SEC_TO_UINT64)
+    g_warning("Conversion from uint64 to non precise LttTime");
+#endif //EXTRA_CHECK
   LttTime res;
-  res.tv_sec = t1;
-  res.tv_nsec = (t1 - res.tv_sec) * NANOSECONDS_PER_SECOND;
+  if(unlikely(t1 >= NANOSECONDS_PER_SECOND)) {
+    res.tv_sec = t1/NANOSECONDS_PER_SECOND;
+    res.tv_nsec = (t1 - res.tv_sec*NANOSECONDS_PER_SECOND);
+  } else {
+    res.tv_sec = 0;
+    res.tv_nsec = (guint32)t1;
+  }
   return res;
 }