LCOV - code coverage report
Current view: top level - lkbce/include/linux - ktime.h (source / functions) Hit Total Coverage
Test: coverage.info Lines: 1 1 100.0 %
Date: 2017-01-25 Functions: 0 0 -

          Line data    Source code
       1             : /*
       2             :  *  include/linux/ktime.h
       3             :  *
       4             :  *  ktime_t - nanosecond-resolution time format.
       5             :  *
       6             :  *   Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
       7             :  *   Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
       8             :  *
       9             :  *  data type definitions, declarations, prototypes and macros.
      10             :  *
      11             :  *  Started by: Thomas Gleixner and Ingo Molnar
      12             :  *
      13             :  *  Credits:
      14             :  *
      15             :  *      Roman Zippel provided the ideas and primary code snippets of
      16             :  *      the ktime_t union and further simplifications of the original
      17             :  *      code.
      18             :  *
      19             :  *  For licencing details see kernel-base/COPYING
      20             :  */
      21             : #ifndef _LINUX_KTIME_H
      22             : #define _LINUX_KTIME_H
      23             : 
      24             : #include <linux/time.h>
      25             : #include <linux/jiffies.h>
      26             : 
      27             : /*
      28             :  * ktime_t:
      29             :  *
      30             :  * On 64-bit CPUs a single 64-bit variable is used to store the hrtimers
      31             :  * internal representation of time values in scalar nanoseconds. The
      32             :  * design plays out best on 64-bit CPUs, where most conversions are
      33             :  * NOPs and most arithmetic ktime_t operations are plain arithmetic
      34             :  * operations.
      35             :  *
      36             :  * On 32-bit CPUs an optimized representation of the timespec structure
      37             :  * is used to avoid expensive conversions from and to timespecs. The
      38             :  * endian-aware order of the tv struct members is choosen to allow
      39             :  * mathematical operations on the tv64 member of the union too, which
      40             :  * for certain operations produces better code.
      41             :  *
      42             :  * For architectures with efficient support for 64/32-bit conversions the
      43             :  * plain scalar nanosecond based representation can be selected by the
      44             :  * config switch CONFIG_KTIME_SCALAR.
      45             :  */
      46             : union ktime {
      47             :         s64     tv64;
      48             : #if BITS_PER_LONG != 64 && !defined(CONFIG_KTIME_SCALAR)
      49             :         struct {
      50             : # ifdef __BIG_ENDIAN
      51             :         s32     sec, nsec;
      52             : # else
      53             :         s32     nsec, sec;
      54             : # endif
      55             :         } tv;
      56             : #endif
      57             : };
      58             : 
      59           1 : typedef union ktime ktime_t;            /* Kill this */
      60             : 
      61             : #define KTIME_MAX                       ((s64)~((u64)1 << 63))
      62             : #if (BITS_PER_LONG == 64)
      63             : # define KTIME_SEC_MAX                  (KTIME_MAX / NSEC_PER_SEC)
      64             : #else
      65             : # define KTIME_SEC_MAX                  LONG_MAX
      66             : #endif
      67             : 
      68             : /*
      69             :  * ktime_t definitions when using the 64-bit scalar representation:
      70             :  */
      71             : 
      72             : #if (BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)
      73             : 
      74             : /**
      75             :  * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
      76             :  * @secs:       seconds to set
      77             :  * @nsecs:      nanoseconds to set
      78             :  *
      79             :  * Return the ktime_t representation of the value
      80             :  */
      81             : static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
      82             : {
      83             : #if (BITS_PER_LONG == 64)
      84             :         if (unlikely(secs >= KTIME_SEC_MAX))
      85             :                 return (ktime_t){ .tv64 = KTIME_MAX };
      86             : #endif
      87             :         return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs };
      88             : }
      89             : 
      90             : /* Subtract two ktime_t variables. rem = lhs -rhs: */
      91             : #define ktime_sub(lhs, rhs) \
      92             :                 ({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })
      93             : 
      94             : /* Add two ktime_t variables. res = lhs + rhs: */
      95             : #define ktime_add(lhs, rhs) \
      96             :                 ({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
      97             : 
      98             : /*
      99             :  * Add a ktime_t variable and a scalar nanosecond value.
     100             :  * res = kt + nsval:
     101             :  */
     102             : #define ktime_add_ns(kt, nsval) \
     103             :                 ({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })
     104             : 
     105             : /*
     106             :  * Subtract a scalar nanosecod from a ktime_t variable
     107             :  * res = kt - nsval:
     108             :  */
     109             : #define ktime_sub_ns(kt, nsval) \
     110             :                 ({ (ktime_t){ .tv64 = (kt).tv64 - (nsval) }; })
     111             : 
     112             : /* convert a timespec to ktime_t format: */
     113             : static inline ktime_t timespec_to_ktime(struct timespec ts)
     114             : {
     115             :         return ktime_set(ts.tv_sec, ts.tv_nsec);
     116             : }
     117             : 
     118             : /* convert a timeval to ktime_t format: */
     119             : static inline ktime_t timeval_to_ktime(struct timeval tv)
     120             : {
     121             :         return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
     122             : }
     123             : 
     124             : /* Map the ktime_t to timespec conversion to ns_to_timespec function */
     125             : #define ktime_to_timespec(kt)           ns_to_timespec((kt).tv64)
     126             : 
     127             : /* Map the ktime_t to timeval conversion to ns_to_timeval function */
     128             : #define ktime_to_timeval(kt)            ns_to_timeval((kt).tv64)
     129             : 
     130             : /* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
     131             : #define ktime_to_ns(kt)                 ((kt).tv64)
     132             : 
     133             : #else
     134             : 
     135             : /*
     136             :  * Helper macros/inlines to get the ktime_t math right in the timespec
     137             :  * representation. The macros are sometimes ugly - their actual use is
     138             :  * pretty okay-ish, given the circumstances. We do all this for
     139             :  * performance reasons. The pure scalar nsec_t based code was nice and
     140             :  * simple, but created too many 64-bit / 32-bit conversions and divisions.
     141             :  *
     142             :  * Be especially aware that negative values are represented in a way
     143             :  * that the tv.sec field is negative and the tv.nsec field is greater
     144             :  * or equal to zero but less than nanoseconds per second. This is the
     145             :  * same representation which is used by timespecs.
     146             :  *
     147             :  *   tv.sec < 0 and 0 >= tv.nsec < NSEC_PER_SEC
     148             :  */
     149             : 
     150             : /* Set a ktime_t variable to a value in sec/nsec representation: */
     151             : static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
     152             : {
     153             :         return (ktime_t) { .tv = { .sec = secs, .nsec = nsecs } };
     154             : }
     155             : 
     156             : /**
     157             :  * ktime_sub - subtract two ktime_t variables
     158             :  * @lhs:        minuend
     159             :  * @rhs:        subtrahend
     160             :  *
     161             :  * Returns the remainder of the substraction
     162             :  */
     163             : static inline ktime_t ktime_sub(const ktime_t lhs, const ktime_t rhs)
     164             : {
     165             :         ktime_t res;
     166             : 
     167             :         res.tv64 = lhs.tv64 - rhs.tv64;
     168             :         if (res.tv.nsec < 0)
     169             :                 res.tv.nsec += NSEC_PER_SEC;
     170             : 
     171             :         return res;
     172             : }
     173             : 
     174             : /**
     175             :  * ktime_add - add two ktime_t variables
     176             :  * @add1:       addend1
     177             :  * @add2:       addend2
     178             :  *
     179             :  * Returns the sum of @add1 and @add2.
     180             :  */
     181             : static inline ktime_t ktime_add(const ktime_t add1, const ktime_t add2)
     182             : {
     183             :         ktime_t res;
     184             : 
     185             :         res.tv64 = add1.tv64 + add2.tv64;
     186             :         /*
     187             :          * performance trick: the (u32) -NSEC gives 0x00000000Fxxxxxxx
     188             :          * so we subtract NSEC_PER_SEC and add 1 to the upper 32 bit.
     189             :          *
     190             :          * it's equivalent to:
     191             :          *   tv.nsec -= NSEC_PER_SEC
     192             :          *   tv.sec ++;
     193             :          */
     194             :         if (res.tv.nsec >= NSEC_PER_SEC)
     195             :                 res.tv64 += (u32)-NSEC_PER_SEC;
     196             : 
     197             :         return res;
     198             : }
     199             : 
     200             : /**
     201             :  * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
     202             :  * @kt:         addend
     203             :  * @nsec:       the scalar nsec value to add
     204             :  *
     205             :  * Returns the sum of @kt and @nsec in ktime_t format
     206             :  */
     207             : extern ktime_t ktime_add_ns(const ktime_t kt, u64 nsec);
     208             : 
     209             : /**
     210             :  * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
     211             :  * @kt:         minuend
     212             :  * @nsec:       the scalar nsec value to subtract
     213             :  *
     214             :  * Returns the subtraction of @nsec from @kt in ktime_t format
     215             :  */
     216             : extern ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec);
     217             : 
     218             : /**
     219             :  * timespec_to_ktime - convert a timespec to ktime_t format
     220             :  * @ts:         the timespec variable to convert
     221             :  *
     222             :  * Returns a ktime_t variable with the converted timespec value
     223             :  */
     224             : static inline ktime_t timespec_to_ktime(const struct timespec ts)
     225             : {
     226             :         return (ktime_t) { .tv = { .sec = (s32)ts.tv_sec,
     227             :                                    .nsec = (s32)ts.tv_nsec } };
     228             : }
     229             : 
     230             : /**
     231             :  * timeval_to_ktime - convert a timeval to ktime_t format
     232             :  * @tv:         the timeval variable to convert
     233             :  *
     234             :  * Returns a ktime_t variable with the converted timeval value
     235             :  */
     236             : static inline ktime_t timeval_to_ktime(const struct timeval tv)
     237             : {
     238             :         return (ktime_t) { .tv = { .sec = (s32)tv.tv_sec,
     239             :                                    .nsec = (s32)tv.tv_usec * 1000 } };
     240             : }
     241             : 
     242             : /**
     243             :  * ktime_to_timespec - convert a ktime_t variable to timespec format
     244             :  * @kt:         the ktime_t variable to convert
     245             :  *
     246             :  * Returns the timespec representation of the ktime value
     247             :  */
     248             : static inline struct timespec ktime_to_timespec(const ktime_t kt)
     249             : {
     250             :         return (struct timespec) { .tv_sec = (time_t) kt.tv.sec,
     251             :                                    .tv_nsec = (long) kt.tv.nsec };
     252             : }
     253             : 
     254             : /**
     255             :  * ktime_to_timeval - convert a ktime_t variable to timeval format
     256             :  * @kt:         the ktime_t variable to convert
     257             :  *
     258             :  * Returns the timeval representation of the ktime value
     259             :  */
     260             : static inline struct timeval ktime_to_timeval(const ktime_t kt)
     261             : {
     262             :         return (struct timeval) {
     263             :                 .tv_sec = (time_t) kt.tv.sec,
     264             :                 .tv_usec = (suseconds_t) (kt.tv.nsec / NSEC_PER_USEC) };
     265             : }
     266             : 
     267             : /**
     268             :  * ktime_to_ns - convert a ktime_t variable to scalar nanoseconds
     269             :  * @kt:         the ktime_t variable to convert
     270             :  *
     271             :  * Returns the scalar nanoseconds representation of @kt
     272             :  */
     273             : static inline s64 ktime_to_ns(const ktime_t kt)
     274             : {
     275             :         return (s64) kt.tv.sec * NSEC_PER_SEC + kt.tv.nsec;
     276             : }
     277             : 
     278             : #endif
     279             : 
     280             : /**
     281             :  * ktime_equal - Compares two ktime_t variables to see if they are equal
     282             :  * @cmp1:       comparable1
     283             :  * @cmp2:       comparable2
     284             :  *
     285             :  * Compare two ktime_t variables, returns 1 if equal
     286             :  */
     287             : static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2)
     288             : {
     289             :         return cmp1.tv64 == cmp2.tv64;
     290             : }
     291             : 
     292             : static inline s64 ktime_to_us(const ktime_t kt)
     293             : {
     294             :         struct timeval tv = ktime_to_timeval(kt);
     295             :         return (s64) tv.tv_sec * USEC_PER_SEC + tv.tv_usec;
     296             : }
     297             : 
     298             : static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
     299             : {
     300             :        return ktime_to_us(ktime_sub(later, earlier));
     301             : }
     302             : 
     303             : static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
     304             : {
     305             :         return ktime_add_ns(kt, usec * 1000);
     306             : }
     307             : 
     308             : static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
     309             : {
     310             :         return ktime_sub_ns(kt, usec * 1000);
     311             : }
     312             : 
     313             : extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);
     314             : 
     315             : /*
     316             :  * The resolution of the clocks. The resolution value is returned in
     317             :  * the clock_getres() system call to give application programmers an
     318             :  * idea of the (in)accuracy of timers. Timer values are rounded up to
     319             :  * this resolution values.
     320             :  */
     321             : #define LOW_RES_NSEC            TICK_NSEC
     322             : #define KTIME_LOW_RES           (ktime_t){ .tv64 = LOW_RES_NSEC }
     323             : 
     324             : /* Get the monotonic time in timespec format: */
     325             : extern void ktime_get_ts(struct timespec *ts);
     326             : 
     327             : /* Get the real (wall-) time in timespec format: */
     328             : #define ktime_get_real_ts(ts)   getnstimeofday(ts)
     329             : 
     330             : static inline ktime_t ns_to_ktime(u64 ns)
     331             : {
     332             :         static const ktime_t ktime_zero = { .tv64 = 0 };
     333             :         return ktime_add_ns(ktime_zero, ns);
     334             : }
     335             : 
     336             : #endif

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