Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 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 | * |
Thomas Gleixner | 66188fa | 2006-02-01 03:05:13 -0800 | [diff] [blame] | 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 | * |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 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 | typedef union { |
| 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 | } ktime_t; |
| 58 | |
Thomas Gleixner | 96dd742 | 2006-09-06 00:03:42 -0700 | [diff] [blame] | 59 | #define KTIME_MAX ((s64)~((u64)1 << 63)) |
| 60 | #define KTIME_SEC_MAX (KTIME_MAX / NSEC_PER_SEC) |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 61 | |
| 62 | /* |
| 63 | * ktime_t definitions when using the 64-bit scalar representation: |
| 64 | */ |
| 65 | |
| 66 | #if (BITS_PER_LONG == 64) || defined(CONFIG_KTIME_SCALAR) |
| 67 | |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 68 | /** |
| 69 | * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 70 | * @secs: seconds to set |
| 71 | * @nsecs: nanoseconds to set |
| 72 | * |
| 73 | * Return the ktime_t representation of the value |
| 74 | */ |
| 75 | static inline ktime_t ktime_set(const long secs, const unsigned long nsecs) |
| 76 | { |
Thomas Gleixner | 96dd742 | 2006-09-06 00:03:42 -0700 | [diff] [blame] | 77 | #if (BITS_PER_LONG == 64) |
| 78 | if (unlikely(secs >= KTIME_SEC_MAX)) |
| 79 | return (ktime_t){ .tv64 = KTIME_MAX }; |
| 80 | #endif |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 81 | return (ktime_t) { .tv64 = (s64)secs * NSEC_PER_SEC + (s64)nsecs }; |
| 82 | } |
| 83 | |
| 84 | /* Subtract two ktime_t variables. rem = lhs -rhs: */ |
| 85 | #define ktime_sub(lhs, rhs) \ |
| 86 | ({ (ktime_t){ .tv64 = (lhs).tv64 - (rhs).tv64 }; }) |
| 87 | |
| 88 | /* Add two ktime_t variables. res = lhs + rhs: */ |
| 89 | #define ktime_add(lhs, rhs) \ |
| 90 | ({ (ktime_t){ .tv64 = (lhs).tv64 + (rhs).tv64 }; }) |
| 91 | |
| 92 | /* |
| 93 | * Add a ktime_t variable and a scalar nanosecond value. |
| 94 | * res = kt + nsval: |
| 95 | */ |
| 96 | #define ktime_add_ns(kt, nsval) \ |
| 97 | ({ (ktime_t){ .tv64 = (kt).tv64 + (nsval) }; }) |
| 98 | |
| 99 | /* convert a timespec to ktime_t format: */ |
Roman Zippel | b2ee9db | 2006-02-15 15:17:40 -0800 | [diff] [blame] | 100 | static inline ktime_t timespec_to_ktime(struct timespec ts) |
| 101 | { |
| 102 | return ktime_set(ts.tv_sec, ts.tv_nsec); |
| 103 | } |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 104 | |
| 105 | /* convert a timeval to ktime_t format: */ |
Roman Zippel | b2ee9db | 2006-02-15 15:17:40 -0800 | [diff] [blame] | 106 | static inline ktime_t timeval_to_ktime(struct timeval tv) |
| 107 | { |
| 108 | return ktime_set(tv.tv_sec, tv.tv_usec * NSEC_PER_USEC); |
| 109 | } |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 110 | |
| 111 | /* Map the ktime_t to timespec conversion to ns_to_timespec function */ |
| 112 | #define ktime_to_timespec(kt) ns_to_timespec((kt).tv64) |
| 113 | |
| 114 | /* Map the ktime_t to timeval conversion to ns_to_timeval function */ |
| 115 | #define ktime_to_timeval(kt) ns_to_timeval((kt).tv64) |
| 116 | |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 117 | /* Convert ktime_t to nanoseconds - NOP in the scalar storage format: */ |
| 118 | #define ktime_to_ns(kt) ((kt).tv64) |
| 119 | |
| 120 | #else |
| 121 | |
| 122 | /* |
| 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. |
| 128 | * |
| 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. |
| 133 | * |
| 134 | * tv.sec < 0 and 0 >= tv.nsec < NSEC_PER_SEC |
| 135 | */ |
| 136 | |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 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) |
| 139 | { |
| 140 | return (ktime_t) { .tv = { .sec = secs, .nsec = nsecs } }; |
| 141 | } |
| 142 | |
| 143 | /** |
| 144 | * ktime_sub - subtract two ktime_t variables |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 145 | * @lhs: minuend |
| 146 | * @rhs: subtrahend |
| 147 | * |
| 148 | * Returns the remainder of the substraction |
| 149 | */ |
| 150 | static inline ktime_t ktime_sub(const ktime_t lhs, const ktime_t rhs) |
| 151 | { |
| 152 | ktime_t res; |
| 153 | |
| 154 | res.tv64 = lhs.tv64 - rhs.tv64; |
| 155 | if (res.tv.nsec < 0) |
| 156 | res.tv.nsec += NSEC_PER_SEC; |
| 157 | |
| 158 | return res; |
| 159 | } |
| 160 | |
| 161 | /** |
| 162 | * ktime_add - add two ktime_t variables |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 163 | * @add1: addend1 |
| 164 | * @add2: addend2 |
| 165 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame^] | 166 | * Returns the sum of @add1 and @add2. |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 167 | */ |
| 168 | static inline ktime_t ktime_add(const ktime_t add1, const ktime_t add2) |
| 169 | { |
| 170 | ktime_t res; |
| 171 | |
| 172 | res.tv64 = add1.tv64 + add2.tv64; |
| 173 | /* |
| 174 | * performance trick: the (u32) -NSEC gives 0x00000000Fxxxxxxx |
| 175 | * so we subtract NSEC_PER_SEC and add 1 to the upper 32 bit. |
| 176 | * |
| 177 | * it's equivalent to: |
| 178 | * tv.nsec -= NSEC_PER_SEC |
| 179 | * tv.sec ++; |
| 180 | */ |
| 181 | if (res.tv.nsec >= NSEC_PER_SEC) |
| 182 | res.tv64 += (u32)-NSEC_PER_SEC; |
| 183 | |
| 184 | return res; |
| 185 | } |
| 186 | |
| 187 | /** |
| 188 | * ktime_add_ns - Add a scalar nanoseconds value to a ktime_t variable |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 189 | * @kt: addend |
| 190 | * @nsec: the scalar nsec value to add |
| 191 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame^] | 192 | * Returns the sum of @kt and @nsec in ktime_t format |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 193 | */ |
| 194 | extern ktime_t ktime_add_ns(const ktime_t kt, u64 nsec); |
| 195 | |
| 196 | /** |
| 197 | * timespec_to_ktime - convert a timespec to ktime_t format |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 198 | * @ts: the timespec variable to convert |
| 199 | * |
| 200 | * Returns a ktime_t variable with the converted timespec value |
| 201 | */ |
| 202 | static inline ktime_t timespec_to_ktime(const struct timespec ts) |
| 203 | { |
| 204 | return (ktime_t) { .tv = { .sec = (s32)ts.tv_sec, |
| 205 | .nsec = (s32)ts.tv_nsec } }; |
| 206 | } |
| 207 | |
| 208 | /** |
| 209 | * timeval_to_ktime - convert a timeval to ktime_t format |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 210 | * @tv: the timeval variable to convert |
| 211 | * |
| 212 | * Returns a ktime_t variable with the converted timeval value |
| 213 | */ |
| 214 | static inline ktime_t timeval_to_ktime(const struct timeval tv) |
| 215 | { |
| 216 | return (ktime_t) { .tv = { .sec = (s32)tv.tv_sec, |
| 217 | .nsec = (s32)tv.tv_usec * 1000 } }; |
| 218 | } |
| 219 | |
| 220 | /** |
| 221 | * ktime_to_timespec - convert a ktime_t variable to timespec format |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 222 | * @kt: the ktime_t variable to convert |
| 223 | * |
| 224 | * Returns the timespec representation of the ktime value |
| 225 | */ |
| 226 | static inline struct timespec ktime_to_timespec(const ktime_t kt) |
| 227 | { |
| 228 | return (struct timespec) { .tv_sec = (time_t) kt.tv.sec, |
| 229 | .tv_nsec = (long) kt.tv.nsec }; |
| 230 | } |
| 231 | |
| 232 | /** |
| 233 | * ktime_to_timeval - convert a ktime_t variable to timeval format |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 234 | * @kt: the ktime_t variable to convert |
| 235 | * |
| 236 | * Returns the timeval representation of the ktime value |
| 237 | */ |
| 238 | static inline struct timeval ktime_to_timeval(const ktime_t kt) |
| 239 | { |
| 240 | return (struct timeval) { |
| 241 | .tv_sec = (time_t) kt.tv.sec, |
| 242 | .tv_usec = (suseconds_t) (kt.tv.nsec / NSEC_PER_USEC) }; |
| 243 | } |
| 244 | |
| 245 | /** |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 246 | * ktime_to_ns - convert a ktime_t variable to scalar nanoseconds |
| 247 | * @kt: the ktime_t variable to convert |
| 248 | * |
Robert P. J. Day | 72fd4a3 | 2007-02-10 01:45:59 -0800 | [diff] [blame^] | 249 | * Returns the scalar nanoseconds representation of @kt |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 250 | */ |
Thomas Gleixner | cfd1893 | 2006-12-06 20:37:38 -0800 | [diff] [blame] | 251 | static inline s64 ktime_to_ns(const ktime_t kt) |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 252 | { |
Thomas Gleixner | cfd1893 | 2006-12-06 20:37:38 -0800 | [diff] [blame] | 253 | return (s64) kt.tv.sec * NSEC_PER_SEC + kt.tv.nsec; |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 254 | } |
| 255 | |
| 256 | #endif |
| 257 | |
Thomas Gleixner | c0a3132 | 2006-01-09 20:52:32 -0800 | [diff] [blame] | 258 | /* |
| 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. |
| 263 | */ |
Thomas Gleixner | e278763 | 2006-01-12 11:36:14 +0100 | [diff] [blame] | 264 | #define KTIME_REALTIME_RES (ktime_t){ .tv64 = TICK_NSEC } |
| 265 | #define KTIME_MONOTONIC_RES (ktime_t){ .tv64 = TICK_NSEC } |
Thomas Gleixner | c0a3132 | 2006-01-09 20:52:32 -0800 | [diff] [blame] | 266 | |
| 267 | /* Get the monotonic time in timespec format: */ |
| 268 | extern void ktime_get_ts(struct timespec *ts); |
| 269 | |
| 270 | /* Get the real (wall-) time in timespec format: */ |
| 271 | #define ktime_get_real_ts(ts) getnstimeofday(ts) |
| 272 | |
Thomas Gleixner | 97fc79f | 2006-01-09 20:52:31 -0800 | [diff] [blame] | 273 | #endif |