X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=ltt%2Fbranches%2Fpoly%2Fltt%2Ftime.h;h=6ab53fcac3039310e11dae5c4593c91dee4be5f9;hb=57df94dd8dd13258d6a5a83406f2f76a045a7cc3;hp=61c3e596c3e0bb2ca76707fa12b738be27471ab2;hpb=18206708bafbba3198bfb82cca97f17d70a05666;p=lttv.git diff --git a/ltt/branches/poly/ltt/time.h b/ltt/branches/poly/ltt/time.h index 61c3e596..6ab53fca 100644 --- a/ltt/branches/poly/ltt/time.h +++ b/ltt/branches/poly/ltt/time.h @@ -20,7 +20,7 @@ #define LTT_TIME_H #include - +#include typedef struct _LttTime { unsigned long tv_sec; @@ -28,24 +28,34 @@ typedef struct _LttTime { } LttTime; -static const unsigned long NANOSECONDS_PER_SECOND = 1000000000; +#define NANOSECONDS_PER_SECOND 1000000000 +/* 2^30/1.07374182400631629848 = 1000000000.0 */ +#define DOUBLE_SHIFT_CONST 1.07374182400631629848 +#define DOUBLE_SHIFT 30 + +/* 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}; +static const LttTime ltt_time_zero = { 0, 0 }; static const LttTime ltt_time_one = { 0, 1 }; -static const LttTime ltt_time_infinite = { G_MAXUINT, G_MAXUINT }; +static const LttTime ltt_time_infinite = { G_MAXUINT, NANOSECONDS_PER_SECOND }; 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 +64,101 @@ 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)((guint64)t1.tv_sec< 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 * DOUBLE_SHIFT_CONST) >> DOUBLE_SHIFT; + res.tv_nsec = (t1 - (((guint64)res.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; + return (guint64)((t1.tv_sec*LTT_TIME_UINT_SHIFT_CONST) >> LTT_TIME_UINT_SHIFT) + + (guint64)t1.tv_nsec; } -static inline double ltt_time_to_double(LttTime t1) -{ - return (double)t1.tv_sec + (double)t1.tv_nsec / NANOSECONDS_PER_SECOND; -} +#define MAX_TV_SEC_TO_UINT64 0x3FFFFFFFFFFFFFFFULL - -static inline LttTime ltt_time_from_double(double t1) +/* 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 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)) { + 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; }