X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=ltt%2Fbranches%2Fpoly%2Fltt%2Ftime.h;h=2bf3048e2f8b9ecbf234ce4bacc73dea9106c386;hb=ddf83b7f8d740a52adfbfabc8d6864a6fc6f83a2;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..2bf3048e 100644 --- a/ltt/branches/poly/ltt/time.h +++ b/ltt/branches/poly/ltt/time.h @@ -1,5 +1,6 @@ /* This file is part of the Linux Trace Toolkit trace reading library * Copyright (C) 2003-2004 Michel Dagenais + * 2005 Mathieu Desnoyers * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -20,7 +21,8 @@ #define LTT_TIME_H #include - +#include +#include typedef struct _LttTime { unsigned long tv_sec; @@ -30,6 +32,21 @@ typedef struct _LttTime { #define NANOSECONDS_PER_SECOND 1000000000 +/* 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 }; static const LttTime ltt_time_one = { 0, 1 }; @@ -40,12 +57,14 @@ 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 +73,105 @@ 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; + if(likely((long)t1.tv_sec - (long)t2.tv_sec > 0)) ret = 1; + else if(unlikely((long)t1.tv_sec - (long)t2.tv_sec < 0)) ret = -1; + else if(likely((long)t1.tv_nsec - (long)t2.tv_nsec > 0)) ret = 1; + else if(unlikely((long)t1.tv_nsec - (long)t2.tv_nsec < 0)) 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_DIV) >> 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; } -#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; -} +#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 (2^23)-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)) { + 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; }