summaryrefslogtreecommitdiffstats
path: root/include/linux/ktime.h
blob: e1ceaa9b36bbaa5e975450c30d9311c8af946be8 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
/*
 *  include/linux/ktime.h
 *
 *  ktime_t - nanosecond-resolution time format.
 *
 *   Copyright(C) 2005, Thomas Gleixner <tglx@linutronix.de>
 *   Copyright(C) 2005, Red Hat, Inc., Ingo Molnar
 *
 *  data type definitions, declarations, prototypes and macros.
 *
 *  Started by: Thomas Gleixner and Ingo Molnar
 *
 *  Credits:
 *
 *  	Roman Zippel provided the ideas and primary code snippets of
 *  	the ktime_t union and further simplifications of the original
 *  	code.
 *
 *  For licencing details see kernel-base/COPYING
 */
#ifndef _LINUX_KTIME_H
#define _LINUX_KTIME_H

#include <linux/time.h>
#include <linux/jiffies.h>

/*
 * ktime_t:
 *
 * On 64-bit CPUs a single 64-bit variable is used to store the hrtimers
 * internal representation of time values in scalar nanoseconds. The
 * design plays out best on 64-bit CPUs, where most conversions are
 * NOPs and most arithmetic ktime_t operations are plain arithmetic
 * operations.
 *
 * On 32-bit CPUs an optimized representation of the timespec structure
 * is used to avoid expensive conversions from and to timespecs. The
 * endian-aware order of the tv struct members is choosen to allow
 * mathematical operations on the tv64 member of the union too, which
 * for certain operations produces better code.
 *
 * For architectures with efficient support for 64/32-bit conversions the
 * plain scalar nanosecond based representation can be selected by the
 * config switch CONFIG_KTIME_SCALAR.
 */
union ktime {
	s64	tv64;
#if BITS_PER_LONG != 64 && !defined(CONFIG_KTIME_SCALAR)
	struct {
# ifdef __BIG_ENDIAN
	s32	sec, nsec;
# else
	s32	nsec, sec;
# endif
	} tv;
#endif
};

typedef union ktime ktime_t;		/* Kill this */

#define KTIME_MAX			((s64)~((u64)1 << 63))
#if (BITS_PER_LONG == 64)
# define KTIME_SEC_MAX			(KTIME_MAX / NSEC_PER_SEC)
#else
# define KTIME_SEC_MAX			LONG_MAX
#endif

/*
 * ktime_t definitions when using the 64-bit scalar representation:
 */

#if (BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)

/**
 * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value
 * @secs:	seconds to set
 * @nsecs:	nanoseconds to set
 *
 * Return the ktime_t representation of the value
 */
static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
{
#if (BITS_PER_LONG == 64)
	if (unlikely(secs >= KTIME_SEC_MAX))
		return (ktime_t){ .tv64 = KTIME_MAX };
#endif
	return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs };
}

/* Subtract two ktime_t variables. rem = lhs -rhs: */
#define ktime_sub(lhs, rhs) \
		({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; })

/* Add two ktime_t variables. res = lhs + rhs: */
#define ktime_add(lhs, rhs) \
		({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; })

/*
 * Add a ktime_t variable and a scalar nanosecond value.
 * res = kt + nsval:
 */
#define ktime_add_ns(kt, nsval) \
		({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; })

/*
 * Subtract a scalar nanosecod from a ktime_t variable
 * res = kt - nsval:
 */
#define ktime_sub_ns(kt, nsval) \
		({ (ktime_t){ .tv64 = (kt).tv64 - (nsval) }; })

/* convert a timespec to ktime_t format: */
static inline ktime_t timespec_to_ktime(struct timespec ts)
{
	return ktime_set(ts.tv_sec, ts.tv_nsec);
}

/* convert a timeval to ktime_t format: */
static inline ktime_t timeval_to_ktime(struct timeval tv)
{
	return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC);
}

/* Map the ktime_t to timespec conversion to ns_to_timespec function */
#define ktime_to_timespec(kt)		ns_to_timespec((kt).tv64)

/* Map the ktime_t to timeval conversion to ns_to_timeval function */
#define ktime_to_timeval(kt)		ns_to_timeval((kt).tv64)

/* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */
#define ktime_to_ns(kt)			((kt).tv64)

#else	/* !((BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)) */

/*
 * Helper macros/inlines to get the ktime_t math right in the timespec
 * representation. The macros are sometimes ugly - their actual use is
 * pretty okay-ish, given the circumstances. We do all this for
 * performance reasons. The pure scalar nsec_t based code was nice and
 * simple, but created too many 64-bit / 32-bit conversions and divisions.
 *
 * Be especially aware that negative values are represented in a way
 * that the tv.sec field is negative and the tv.nsec field is greater
 * or equal to zero but less than nanoseconds per second. This is the
 * same representation which is used by timespecs.
 *
 *   tv.sec < 0 and 0 >= tv.nsec < NSEC_PER_SEC
 */

/* Set a ktime_t variable to a value in sec/nsec representation: */
static inline ktime_t ktime_set(const long secs, const unsigned long nsecs)
{
	return (ktime_t) { .tv = { .sec = secs, .nsec = nsecs } };
}

/**
 * ktime_sub - subtract two ktime_t variables
 * @lhs:	minuend
 * @rhs:	subtrahend
 *
 * Returns the remainder of the substraction
 */
static inline ktime_t ktime_sub(const ktime_t lhs, const ktime_t rhs)
{
	ktime_t res;

	res.tv64 = lhs.tv64 - rhs.tv64;
	if (res.tv.nsec < 0)
		res.tv.nsec += NSEC_PER_SEC;

	return res;
}

/**
 * ktime_add - add two ktime_t variables
 * @add1:	addend1
 * @add2:	addend2
 *
 * Returns the sum of @add1 and @add2.
 */
static inline ktime_t ktime_add(const ktime_t add1, const ktime_t add2)
{
	ktime_t res;

	res.tv64 = add1.tv64 + add2.tv64;
	/*
	 * performance trick: the (u32) -NSEC gives 0x00000000Fxxxxxxx
	 * so we subtract NSEC_PER_SEC and add 1 to the upper 32 bit.
	 *
	 * it's equivalent to:
	 *   tv.nsec -= NSEC_PER_SEC
	 *   tv.sec ++;
	 */
	if (res.tv.nsec >= NSEC_PER_SEC)
		res.tv64 += (u32)-NSEC_PER_SEC;

	return res;
}

/**
 * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable
 * @kt:		addend
 * @nsec:	the scalar nsec value to add
 *
 * Returns the sum of @kt and @nsec in ktime_t format
 */
extern ktime_t ktime_add_ns(const ktime_t kt, u64 nsec);

/**
 * ktime_sub_ns - Subtract a scalar nanoseconds value from a ktime_t variable
 * @kt:		minuend
 * @nsec:	the scalar nsec value to subtract
 *
 * Returns the subtraction of @nsec from @kt in ktime_t format
 */
extern ktime_t ktime_sub_ns(const ktime_t kt, u64 nsec);

/**
 * timespec_to_ktime - convert a timespec to ktime_t format
 * @ts:		the timespec variable to convert
 *
 * Returns a ktime_t variable with the converted timespec value
 */
static inline ktime_t timespec_to_ktime(const struct timespec ts)
{
	return (ktime_t) { .tv = { .sec = (s32)ts.tv_sec,
			   	   .nsec = (s32)ts.tv_nsec } };
}

/**
 * timeval_to_ktime - convert a timeval to ktime_t format
 * @tv:		the timeval variable to convert
 *
 * Returns a ktime_t variable with the converted timeval value
 */
static inline ktime_t timeval_to_ktime(const struct timeval tv)
{
	return (ktime_t) { .tv = { .sec = (s32)tv.tv_sec,
				   .nsec = (s32)tv.tv_usec * 1000 } };
}

/**
 * ktime_to_timespec - convert a ktime_t variable to timespec format
 * @kt:		the ktime_t variable to convert
 *
 * Returns the timespec representation of the ktime value
 */
static inline struct timespec ktime_to_timespec(const ktime_t kt)
{
	return (struct timespec) { .tv_sec = (time_t) kt.tv.sec,
				   .tv_nsec = (long) kt.tv.nsec };
}

/**
 * ktime_to_timeval - convert a ktime_t variable to timeval format
 * @kt:		the ktime_t variable to convert
 *
 * Returns the timeval representation of the ktime value
 */
static inline struct timeval ktime_to_timeval(const ktime_t kt)
{
	return (struct timeval) {
		.tv_sec = (time_t) kt.tv.sec,
		.tv_usec = (suseconds_t) (kt.tv.nsec / NSEC_PER_USEC) };
}

/**
 * ktime_to_ns - convert a ktime_t variable to scalar nanoseconds
 * @kt:		the ktime_t variable to convert
 *
 * Returns the scalar nanoseconds representation of @kt
 */
static inline s64 ktime_to_ns(const ktime_t kt)
{
	return (s64) kt.tv.sec * NSEC_PER_SEC + kt.tv.nsec;
}

#endif	/* !((BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR)) */

/**
 * ktime_equal - Compares two ktime_t variables to see if they are equal
 * @cmp1:	comparable1
 * @cmp2:	comparable2
 *
 * Compare two ktime_t variables, returns 1 if equal
 */
static inline int ktime_equal(const ktime_t cmp1, const ktime_t cmp2)
{
	return cmp1.tv64 == cmp2.tv64;
}

static inline s64 ktime_to_us(const ktime_t kt)
{
	struct timeval tv = ktime_to_timeval(kt);
	return (s64) tv.tv_sec * USEC_PER_SEC + tv.tv_usec;
}

static inline s64 ktime_to_ms(const ktime_t kt)
{
	struct timeval tv = ktime_to_timeval(kt);
	return (s64) tv.tv_sec * MSEC_PER_SEC + tv.tv_usec / USEC_PER_MSEC;
}

static inline s64 ktime_us_delta(const ktime_t later, const ktime_t earlier)
{
       return ktime_to_us(ktime_sub(later, earlier));
}

static inline ktime_t ktime_add_us(const ktime_t kt, const u64 usec)
{
	return ktime_add_ns(kt, usec * 1000);
}

static inline ktime_t ktime_sub_us(const ktime_t kt, const u64 usec)
{
	return ktime_sub_ns(kt, usec * 1000);
}

extern ktime_t ktime_add_safe(const ktime_t lhs, const ktime_t rhs);

/*
 * The resolution of the clocks. The resolution value is returned in
 * the clock_getres() system call to give application programmers an
 * idea of the (in)accuracy of timers. Timer values are rounded up to
 * this resolution values.
 */
#define LOW_RES_NSEC		TICK_NSEC
#define KTIME_LOW_RES		(ktime_t){ .tv64 = LOW_RES_NSEC }

/* Get the monotonic time in timespec format: */
extern void ktime_get_ts(struct timespec *ts);

/* Get the real (wall-) time in timespec format: */
#define ktime_get_real_ts(ts)	getnstimeofday(ts)

static inline ktime_t ns_to_ktime(u64 ns)
{
	static const ktime_t ktime_zero = { .tv64 = 0 };
	return ktime_add_ns(ktime_zero, ns);
}

#endif