1 /* 2 * include/linux/ktime.h 3 * 4 * ktime_t - nanosecond-resolution time format. 5 * 6 * Copyright(C) 2005, Thomas Gleixner <tglx (at) 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 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 59 #define KTIME_MAX ((s64)~((u64)1 << 63)) 60 #define KTIME_SEC_MAX (KTIME_MAX / NSEC_PER_SEC) 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 68 /** 69 * ktime_set - Set a ktime_t variable from a seconds/nanoseconds value 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 { 77 #if (BITS_PER_LONG == 64) 78 if (unlikely(secs >= KTIME_SEC_MAX)) 79 return (ktime_t){ .tv64 = KTIME_MAX }; 80 #endif 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: */ 100 static inline ktime_t timespec_to_ktime(struct timespec ts) 101 { 102 return ktime_set(ts.tv_sec, ts.tv_nsec); 103 } 104 105 /* convert a timeval to ktime_t format: */ 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 } 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) 116 117 /* 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 */ 136 137 /* 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 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 163 * @add1: addend1 164 * @add2: addend2 165 * 166 * Returns the sum of addend1 and addend2 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 189 * @kt: addend 190 * @nsec: the scalar nsec value to add 191 * 192 * Returns the sum of kt and nsec in ktime_t format 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 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 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 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 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 /** 246 * ktime_to_ns - convert a ktime_t variable to scalar nanoseconds 247 * @kt: the ktime_t variable to convert 248 * 249 * Returns the scalar nanoseconds representation of kt 250 */ 251 static inline u64 ktime_to_ns(const ktime_t kt) 252 { 253 return (u64) kt.tv.sec * NSEC_PER_SEC + kt.tv.nsec; 254 } 255 256 #endif 257 258 /* 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 */ 264 #define KTIME_REALTIME_RES (ktime_t){ .tv64 = TICK_NSEC } 265 #define KTIME_MONOTONIC_RES (ktime_t){ .tv64 = TICK_NSEC } 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) 272 273 #endif 274
