#define LTT_TIME_H
#include <glib.h>
-
+#include <ltt/compiler.h>
+#include <math.h>
typedef struct _LttTime {
unsigned long tv_sec;
#define NANOSECONDS_PER_SECOND 1000000000
-#define SHIFT_CONST 1.07374182400631629848
+
+/* We give the DIV and MUL constants so we can always multiply, for a
+ * division as well as a multiplication of NANOSECONDS_PER_SECOND */
+/* 2^30/1.07374182400631629848 = 1000000000.0 */
+#define DOUBLE_SHIFT_CONST_DIV 1.07374182400631629848
+#define DOUBLE_SHIFT 30
+
+/* 2^30*0.93132257461547851562 = 1000000000.0000000000 */
+#define DOUBLE_SHIFT_CONST_MUL 0.93132257461547851562
+
+
+/* 1953125 * 2^9 = NANOSECONDS_PER_SECOND */
+#define LTT_TIME_UINT_SHIFT_CONST 1953125
+#define LTT_TIME_UINT_SHIFT 9
+
static const LttTime ltt_time_zero = { 0, 0 };
LttTime res;
res.tv_sec = t1.tv_sec - t2.tv_sec;
res.tv_nsec = t1.tv_nsec - t2.tv_nsec;
- if(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;
}
LttTime res;
res.tv_nsec = t1.tv_nsec + t2.tv_nsec;
res.tv_sec = t1.tv_sec + t2.tv_sec;
- if(res.tv_nsec >= NANOSECONDS_PER_SECOND) {
+ /* 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;
}
-#define likely(x) __builtin_expect(!!(x), 1)
-#define unlikely(x) __builtin_expect(!!(x), 0)
-
/* Fastest comparison : t1 > t2 */
static inline int ltt_time_compare(LttTime t1, LttTime t2)
{
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;
+ return ((double)((guint64)t1.tv_sec<<DOUBLE_SHIFT)
+ * (double)DOUBLE_SHIFT_CONST_MUL)
+ + (double)t1.tv_nsec;
}
#endif //EXTRA_CHECK
LttTime res;
//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));
+ res.tv_sec = (guint64)(t1 * DOUBLE_SHIFT_CONST_DIV) >> DOUBLE_SHIFT;
+ res.tv_nsec = (t1 - (((guint64)res.tv_sec<<LTT_TIME_UINT_SHIFT))
+ * LTT_TIME_UINT_SHIFT_CONST);
return res;
}
#endif //0
}
+
static inline guint64 ltt_time_to_uint64(LttTime t1)
{
- return (guint64)t1.tv_sec*NANOSECONDS_PER_SECOND
- + (guint64)t1.tv_nsec;
+ return (((guint64)t1.tv_sec*LTT_TIME_UINT_SHIFT_CONST) << LTT_TIME_UINT_SHIFT)
+ + (guint64)t1.tv_nsec;
}
#define MAX_TV_SEC_TO_UINT64 0x3FFFFFFFFFFFFFFFULL
+
+/* The likely branch is with sec != 0, because most events in a bloc
+ * will be over 1s from the block start. (see tracefile.c)
+ */
static inline LttTime ltt_time_from_uint64(guint64 t1)
{
/* We lose precision if tv_sec is > than (2^62)-1
#ifdef EXTRA_CHECK
g_assert(t1 <= MAX_TV_SEC_TO_UINT64);
if(t1 > MAX_TV_SEC_TO_UINT64)
- g_warning("Conversion from non precise uint64 to LttTime");
+ g_warning("Conversion from uint64 to non precise LttTime");
#endif //EXTRA_CHECK
LttTime res;
- res.tv_sec = t1/NANOSECONDS_PER_SECOND;
- res.tv_nsec = (t1 - res.tv_sec*NANOSECONDS_PER_SECOND);
+ //if(unlikely(t1 >= NANOSECONDS_PER_SECOND)) {
+ if(likely(t1>>LTT_TIME_UINT_SHIFT >= LTT_TIME_UINT_SHIFT_CONST)) {
+ //res.tv_sec = t1/NANOSECONDS_PER_SECOND;
+ res.tv_sec = (t1>>LTT_TIME_UINT_SHIFT)
+ /LTT_TIME_UINT_SHIFT_CONST; // acceleration
+ res.tv_nsec = (t1 - res.tv_sec*NANOSECONDS_PER_SECOND);
+ } else {
+ res.tv_sec = 0;
+ res.tv_nsec = (guint32)t1;
+ }
return res;
}