2 * include/linux/ktime.h
4 * ktime_t - nanosecond-resolution time format.
6 * Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
7 * Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
9 * data type definitions, declarations, prototypes and macros.
11 * Started by: Thomas Gleixner and Ingo Molnar
15 * Roman Zippel provided the ideas and primary code snippets of
16 * the ktime_t union and further simplifications of the original
19 * For licencing details see kernel-base/COPYING
21 #ifndef _LINUX_KTIME_H
22 #define _LINUX_KTIME_H
24 #include <linux/time.h>
25 #include <linux/jiffies.h>
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
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 chosen to allow
39 * mathematical operations on the tv64 member of the union too, which
40 * for certain operations produces better code.
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.
48 #if BITS_PER_LONG != 64 && !defined(CONFIG_KTIME_SCALAR)
59 typedef union ktime ktime_t
; /* Kill this */
62 * ktime_t definitions when using the 64-bit scalar representation:
65 #if (BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)
68 * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
69 * @secs: seconds to set
70 * @nsecs: nanoseconds to set
72 * Return: The ktime_t representation of the value.
74 static inline ktime_t
ktime_set(const long secs
, const unsigned long nsecs
)
76 #if (BITS_PER_LONG == 64)
77 if (unlikely(secs
>= KTIME_SEC_MAX
))
78 return (ktime_t
){ .tv64
= KTIME_MAX
};
80 return (ktime_t
) { .tv64
= (s64
)secs
* NSEC_PER_SEC
+ (s64
)nsecs
};
83 /* Subtract two ktime_t variables. rem = lhs -rhs: */
84 #define ktime_sub(lhs, rhs) \
85 ({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })
87 /* Add two ktime_t variables. res = lhs + rhs: */
88 #define ktime_add(lhs, rhs) \
89 ({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
92 * Add a ktime_t variable and a scalar nanosecond value.
95 #define ktime_add_ns(kt, nsval) \
96 ({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })
99 * Subtract a scalar nanosecod from a ktime_t variable
102 #define ktime_sub_ns(kt, nsval) \
103 ({ (ktime_t){ .tv64 = (kt).tv64 - (nsval) }; })
105 /* convert a timespec to ktime_t format: */
106 static inline ktime_t
timespec_to_ktime(struct timespec ts
)
108 return ktime_set(ts
.tv_sec
, ts
.tv_nsec
);
111 /* convert a timeval to ktime_t format: */
112 static inline ktime_t
timeval_to_ktime(struct timeval tv
)
114 return ktime_set(tv
.tv_sec
, tv
.tv_usec
* NSEC_PER_USEC
);
117 /* Map the ktime_t to timespec conversion to ns_to_timespec function */
118 #define ktime_to_timespec(kt) ns_to_timespec((kt).tv64)
120 /* Map the ktime_t to timeval conversion to ns_to_timeval function */
121 #define ktime_to_timeval(kt) ns_to_timeval((kt).tv64)
123 /* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
124 #define ktime_to_ns(kt) ((kt).tv64)
126 #else /* !((BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)) */
129 * Helper macros/inlines to get the ktime_t math right in the timespec
130 * representation. The macros are sometimes ugly - their actual use is
131 * pretty okay-ish, given the circumstances. We do all this for
132 * performance reasons. The pure scalar nsec_t based code was nice and
133 * simple, but created too many 64-bit / 32-bit conversions and divisions.
135 * Be especially aware that negative values are represented in a way
136 * that the tv.sec field is negative and the tv.nsec field is greater
137 * or equal to zero but less than nanoseconds per second. This is the
138 * same representation which is used by timespecs.
140 * tv.sec < 0 and 0 >= tv.nsec < NSEC_PER_SEC
143 /* Set a ktime_t variable to a value in sec/nsec representation: */
144 static inline ktime_t
ktime_set(const long secs
, const unsigned long nsecs
)
146 return (ktime_t
) { .tv
= { .sec
= secs
, .nsec
= nsecs
} };
150 * ktime_sub - subtract two ktime_t variables
154 * Return: The remainder of the subtraction.
156 static inline ktime_t
ktime_sub(const ktime_t lhs
, const ktime_t rhs
)
160 res
.tv64
= lhs
.tv64
- rhs
.tv64
;
162 res
.tv
.nsec
+= NSEC_PER_SEC
;
168 * ktime_add - add two ktime_t variables
172 * Return: The sum of @add1 and @add2.
174 static inline ktime_t
ktime_add(const ktime_t add1
, const ktime_t add2
)
178 res
.tv64
= add1
.tv64
+ add2
.tv64
;
180 * performance trick: the (u32) -NSEC gives 0x00000000Fxxxxxxx
181 * so we subtract NSEC_PER_SEC and add 1 to the upper 32 bit.
183 * it's equivalent to:
184 * tv.nsec -= NSEC_PER_SEC
187 if (res
.tv
.nsec
>= NSEC_PER_SEC
)
188 res
.tv64
+= (u32
)-NSEC_PER_SEC
;
194 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
196 * @nsec: the scalar nsec value to add
198 * Return: The sum of @kt and @nsec in ktime_t format.
200 extern ktime_t
ktime_add_ns(const ktime_t kt
, u64 nsec
);
203 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
205 * @nsec: the scalar nsec value to subtract
207 * Return: The subtraction of @nsec from @kt in ktime_t format.
209 extern ktime_t
ktime_sub_ns(const ktime_t kt
, u64 nsec
);
212 * timespec_to_ktime - convert a timespec to ktime_t format
213 * @ts: the timespec variable to convert
215 * Return: A ktime_t variable with the converted timespec value.
217 static inline ktime_t
timespec_to_ktime(const struct timespec ts
)
219 return (ktime_t
) { .tv
= { .sec
= (s32
)ts
.tv_sec
,
220 .nsec
= (s32
)ts
.tv_nsec
} };
224 * timeval_to_ktime - convert a timeval to ktime_t format
225 * @tv: the timeval variable to convert
227 * Return: A ktime_t variable with the converted timeval value.
229 static inline ktime_t
timeval_to_ktime(const struct timeval tv
)
231 return (ktime_t
) { .tv
= { .sec
= (s32
)tv
.tv_sec
,
232 .nsec
= (s32
)(tv
.tv_usec
*
237 * ktime_to_timespec - convert a ktime_t variable to timespec format
238 * @kt: the ktime_t variable to convert
240 * Return: The timespec representation of the ktime value.
242 static inline struct timespec
ktime_to_timespec(const ktime_t kt
)
244 return (struct timespec
) { .tv_sec
= (time_t) kt
.tv
.sec
,
245 .tv_nsec
= (long) kt
.tv
.nsec
};
249 * ktime_to_timeval - convert a ktime_t variable to timeval format
250 * @kt: the ktime_t variable to convert
252 * Return: The timeval representation of the ktime value.
254 static inline struct timeval
ktime_to_timeval(const ktime_t kt
)
256 return (struct timeval
) {
257 .tv_sec
= (time_t) kt
.tv
.sec
,
258 .tv_usec
= (suseconds_t
) (kt
.tv
.nsec
/ NSEC_PER_USEC
) };
262 * ktime_to_ns - convert a ktime_t variable to scalar nanoseconds
263 * @kt: the ktime_t variable to convert
265 * Return: The scalar nanoseconds representation of @kt.
267 static inline s64
ktime_to_ns(const ktime_t kt
)
269 return (s64
) kt
.tv
.sec
* NSEC_PER_SEC
+ kt
.tv
.nsec
;
272 #endif /* !((BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)) */
275 * ktime_equal - Compares two ktime_t variables to see if they are equal
279 * Compare two ktime_t variables.
281 * Return: 1 if equal.
283 static inline int ktime_equal(const ktime_t cmp1
, const ktime_t cmp2
)
285 return cmp1
.tv64
== cmp2
.tv64
;
289 * ktime_compare - Compares two ktime_t variables for less, greater or equal
294 * cmp1 < cmp2: return <0
295 * cmp1 == cmp2: return 0
296 * cmp1 > cmp2: return >0
298 static inline int ktime_compare(const ktime_t cmp1
, const ktime_t cmp2
)
300 if (cmp1
.tv64
< cmp2
.tv64
)
302 if (cmp1
.tv64
> cmp2
.tv64
)
307 static inline s64
ktime_to_us(const ktime_t kt
)
309 struct timeval tv
= ktime_to_timeval(kt
);
310 return (s64
) tv
.tv_sec
* USEC_PER_SEC
+ tv
.tv_usec
;
313 static inline s64
ktime_to_ms(const ktime_t kt
)
315 struct timeval tv
= ktime_to_timeval(kt
);
316 return (s64
) tv
.tv_sec
* MSEC_PER_SEC
+ tv
.tv_usec
/ USEC_PER_MSEC
;
319 static inline s64
ktime_us_delta(const ktime_t later
, const ktime_t earlier
)
321 return ktime_to_us(ktime_sub(later
, earlier
));
324 static inline ktime_t
ktime_add_us(const ktime_t kt
, const u64 usec
)
326 return ktime_add_ns(kt
, usec
* NSEC_PER_USEC
);
329 static inline ktime_t
ktime_add_ms(const ktime_t kt
, const u64 msec
)
331 return ktime_add_ns(kt
, msec
* NSEC_PER_MSEC
);
334 static inline ktime_t
ktime_sub_us(const ktime_t kt
, const u64 usec
)
336 return ktime_sub_ns(kt
, usec
* NSEC_PER_USEC
);
339 extern ktime_t
ktime_add_safe(const ktime_t lhs
, const ktime_t rhs
);
342 * ktime_to_timespec_cond - convert a ktime_t variable to timespec
343 * format only if the variable contains data
344 * @kt: the ktime_t variable to convert
345 * @ts: the timespec variable to store the result in
347 * Return: %true if there was a successful conversion, %false if kt was 0.
349 static inline __must_check
bool ktime_to_timespec_cond(const ktime_t kt
,
353 *ts
= ktime_to_timespec(kt
);
361 * The resolution of the clocks. The resolution value is returned in
362 * the clock_getres() system call to give application programmers an
363 * idea of the (in)accuracy of timers. Timer values are rounded up to
364 * this resolution values.
366 #define LOW_RES_NSEC TICK_NSEC
367 #define KTIME_LOW_RES (ktime_t){ .tv64 = LOW_RES_NSEC }
369 /* Get the monotonic time in timespec format: */
370 extern void ktime_get_ts(struct timespec
*ts
);
372 /* Get the real (wall-) time in timespec format: */
373 #define ktime_get_real_ts(ts) getnstimeofday(ts)
375 static inline ktime_t
ns_to_ktime(u64 ns
)
377 static const ktime_t ktime_zero
= { .tv64
= 0 };
379 return ktime_add_ns(ktime_zero
, ns
);
382 static inline ktime_t
ms_to_ktime(u64 ms
)
384 static const ktime_t ktime_zero
= { .tv64
= 0 };
386 return ktime_add_ms(ktime_zero
, ms
);