DPDK  2.2.0
rte_time.h
1 /*-
2  * BSD LICENSE
3  *
4  * Copyright(c) 2015 Intel Corporation. All rights reserved.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * * Redistributions of source code must retain the above copyright
12  * notice, this list of conditions and the following disclaimer.
13  * * Redistributions in binary form must reproduce the above copyright
14  * notice, this list of conditions and the following disclaimer in
15  * the documentation and/or other materials provided with the
16  * distribution.
17  * * Neither the name of Intel Corporation nor the names of its
18  * contributors may be used to endorse or promote products derived
19  * from this software without specific prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
24  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
25  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
26  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
27  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
31  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 #define NSEC_PER_SEC 1000000000L
35 
42  uint64_t cycle_last;
44  uint64_t nsec;
46  uint64_t nsec_mask;
48  uint64_t nsec_frac;
50  uint64_t cc_mask;
52  uint32_t cc_shift;
53 };
54 
58 static inline uint64_t
59 rte_cyclecounter_cycles_to_ns(struct rte_timecounter *tc, uint64_t cycles)
60 {
61  uint64_t ns;
62 
63  /* Add fractional nanoseconds. */
64  ns = cycles + tc->nsec_frac;
65  tc->nsec_frac = ns & tc->nsec_mask;
66 
67  /* Shift to get only nanoseconds. */
68  return ns >> tc->cc_shift;
69 }
70 
74 static inline uint64_t
75 rte_timecounter_update(struct rte_timecounter *tc, uint64_t cycle_now)
76 {
77  uint64_t cycle_delta, ns_offset;
78 
79  /* Calculate the delta since the last call. */
80  if (tc->cycle_last <= cycle_now)
81  cycle_delta = (cycle_now - tc->cycle_last) & tc->cc_mask;
82  else
83  /* Handle cycle counts that have wrapped around . */
84  cycle_delta = (~(tc->cycle_last - cycle_now) & tc->cc_mask) + 1;
85 
86  /* Convert to nanoseconds. */
87  ns_offset = rte_cyclecounter_cycles_to_ns(tc, cycle_delta);
88 
89  /* Store current cycle counter for next call. */
90  tc->cycle_last = cycle_now;
91 
92  /* Update the nanosecond count. */
93  tc->nsec += ns_offset;
94 
95  return tc->nsec;
96 }
97 
101 static inline uint64_t
102 rte_timespec_to_ns(const struct timespec *ts)
103 {
104  return ((uint64_t) ts->tv_sec * NSEC_PER_SEC) + ts->tv_nsec;
105 }
106 
110 static inline struct timespec
111 rte_ns_to_timespec(uint64_t nsec)
112 {
113  struct timespec ts = {0, 0};
114 
115  if (nsec == 0)
116  return ts;
117 
118  ts.tv_sec = nsec / NSEC_PER_SEC;
119  ts.tv_nsec = nsec % NSEC_PER_SEC;
120 
121  return ts;
122 }