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git.proxmox.com Git - mirror_ubuntu-eoan-kernel.git/blob - include/linux/ktime.h
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 choosen 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 #define KTIME_MAX ((s64)~((u64)1 << 63))
60 #define KTIME_SEC_MAX (KTIME_MAX / NSEC_PER_SEC)
63 * ktime_t definitions when using the 64-bit scalar representation:
66 #if (BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)
69 * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
70 * @secs: seconds to set
71 * @nsecs: nanoseconds to set
73 * Return the ktime_t representation of the value
75 static inline ktime_t
ktime_set(const long secs
, const unsigned long nsecs
)
77 #if (BITS_PER_LONG == 64)
78 if (unlikely(secs
>= KTIME_SEC_MAX
))
79 return (ktime_t
){ .tv64
= KTIME_MAX
};
81 return (ktime_t
) { .tv64
= (s64
)secs
* NSEC_PER_SEC
+ (s64
)nsecs
};
84 /* Subtract two ktime_t variables. rem = lhs -rhs: */
85 #define ktime_sub(lhs, rhs) \
86 ({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })
88 /* Add two ktime_t variables. res = lhs + rhs: */
89 #define ktime_add(lhs, rhs) \
90 ({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })
93 * Add a ktime_t variable and a scalar nanosecond value.
96 #define ktime_add_ns(kt, nsval) \
97 ({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })
99 /* convert a timespec to ktime_t format: */
100 static inline ktime_t
timespec_to_ktime(struct timespec ts
)
102 return ktime_set(ts
.tv_sec
, ts
.tv_nsec
);
105 /* convert a timeval to ktime_t format: */
106 static inline ktime_t
timeval_to_ktime(struct timeval tv
)
108 return ktime_set(tv
.tv_sec
, tv
.tv_usec
* NSEC_PER_USEC
);
111 /* Map the ktime_t to timespec conversion to ns_to_timespec function */
112 #define ktime_to_timespec(kt) ns_to_timespec((kt).tv64)
114 /* Map the ktime_t to timeval conversion to ns_to_timeval function */
115 #define ktime_to_timeval(kt) ns_to_timeval((kt).tv64)
117 /* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
118 #define ktime_to_ns(kt) ((kt).tv64)
123 * Helper macros/inlines to get the ktime_t math right in the timespec
124 * representation. The macros are sometimes ugly - their actual use is
125 * pretty okay-ish, given the circumstances. We do all this for
126 * performance reasons. The pure scalar nsec_t based code was nice and
127 * simple, but created too many 64-bit / 32-bit conversions and divisions.
129 * Be especially aware that negative values are represented in a way
130 * that the tv.sec field is negative and the tv.nsec field is greater
131 * or equal to zero but less than nanoseconds per second. This is the
132 * same representation which is used by timespecs.
134 * tv.sec < 0 and 0 >= tv.nsec < NSEC_PER_SEC
137 /* Set a ktime_t variable to a value in sec/nsec representation: */
138 static inline ktime_t
ktime_set(const long secs
, const unsigned long nsecs
)
140 return (ktime_t
) { .tv
= { .sec
= secs
, .nsec
= nsecs
} };
144 * ktime_sub - subtract two ktime_t variables
148 * Returns the remainder of the substraction
150 static inline ktime_t
ktime_sub(const ktime_t lhs
, const ktime_t rhs
)
154 res
.tv64
= lhs
.tv64
- rhs
.tv64
;
156 res
.tv
.nsec
+= NSEC_PER_SEC
;
162 * ktime_add - add two ktime_t variables
166 * Returns the sum of addend1 and addend2
168 static inline ktime_t
ktime_add(const ktime_t add1
, const ktime_t add2
)
172 res
.tv64
= add1
.tv64
+ add2
.tv64
;
174 * performance trick: the (u32) -NSEC gives 0x00000000Fxxxxxxx
175 * so we subtract NSEC_PER_SEC and add 1 to the upper 32 bit.
177 * it's equivalent to:
178 * tv.nsec -= NSEC_PER_SEC
181 if (res
.tv
.nsec
>= NSEC_PER_SEC
)
182 res
.tv64
+= (u32
)-NSEC_PER_SEC
;
188 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
190 * @nsec: the scalar nsec value to add
192 * Returns the sum of kt and nsec in ktime_t format
194 extern ktime_t
ktime_add_ns(const ktime_t kt
, u64 nsec
);
197 * timespec_to_ktime - convert a timespec to ktime_t format
198 * @ts: the timespec variable to convert
200 * Returns a ktime_t variable with the converted timespec value
202 static inline ktime_t
timespec_to_ktime(const struct timespec ts
)
204 return (ktime_t
) { .tv
= { .sec
= (s32
)ts
.tv_sec
,
205 .nsec
= (s32
)ts
.tv_nsec
} };
209 * timeval_to_ktime - convert a timeval to ktime_t format
210 * @tv: the timeval variable to convert
212 * Returns a ktime_t variable with the converted timeval value
214 static inline ktime_t
timeval_to_ktime(const struct timeval tv
)
216 return (ktime_t
) { .tv
= { .sec
= (s32
)tv
.tv_sec
,
217 .nsec
= (s32
)tv
.tv_usec
* 1000 } };
221 * ktime_to_timespec - convert a ktime_t variable to timespec format
222 * @kt: the ktime_t variable to convert
224 * Returns the timespec representation of the ktime value
226 static inline struct timespec
ktime_to_timespec(const ktime_t kt
)
228 return (struct timespec
) { .tv_sec
= (time_t) kt
.tv
.sec
,
229 .tv_nsec
= (long) kt
.tv
.nsec
};
233 * ktime_to_timeval - convert a ktime_t variable to timeval format
234 * @kt: the ktime_t variable to convert
236 * Returns the timeval representation of the ktime value
238 static inline struct timeval
ktime_to_timeval(const ktime_t kt
)
240 return (struct timeval
) {
241 .tv_sec
= (time_t) kt
.tv
.sec
,
242 .tv_usec
= (suseconds_t
) (kt
.tv
.nsec
/ NSEC_PER_USEC
) };
246 * ktime_to_ns - convert a ktime_t variable to scalar nanoseconds
247 * @kt: the ktime_t variable to convert
249 * Returns the scalar nanoseconds representation of kt
251 static inline u64
ktime_to_ns(const ktime_t kt
)
253 return (u64
) kt
.tv
.sec
* NSEC_PER_SEC
+ kt
.tv
.nsec
;
259 * The resolution of the clocks. The resolution value is returned in
260 * the clock_getres() system call to give application programmers an
261 * idea of the (in)accuracy of timers. Timer values are rounded up to
262 * this resolution values.
264 #define KTIME_REALTIME_RES (ktime_t){ .tv64 = TICK_NSEC }
265 #define KTIME_MONOTONIC_RES (ktime_t){ .tv64 = TICK_NSEC }
267 /* Get the monotonic time in timespec format: */
268 extern void ktime_get_ts(struct timespec
*ts
);
270 /* Get the real (wall-) time in timespec format: */
271 #define ktime_get_real_ts(ts) getnstimeofday(ts)