1 /**************************************************************************
2 *
3 * Copyright 2008-2010 VMware, Inc.
4 * All Rights Reserved.
5 *
6 * Permission is hereby granted, free of charge, to any person obtaining a
7 * copy of this software and associated documentation files (the
8 * "Software"), to deal in the Software without restriction, including
9 * without limitation the rights to use, copy, modify, merge, publish,
10 * distribute, sub license, and/or sell copies of the Software, and to
11 * permit persons to whom the Software is furnished to do so, subject to
12 * the following conditions:
13 *
14 * The above copyright notice and this permission notice (including the
15 * next paragraph) shall be included in all copies or substantial portions
16 * of the Software.
17 *
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
19 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
20 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
21 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
22 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
23 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
24 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
25 *
26 **************************************************************************/
27
28 /**
29 * @file
30 * OS independent time-manipulation functions.
31 *
32 * @author Jose Fonseca <jfonseca@vmware.com>
33 */
34
35 #ifndef _OS_TIME_H_
36 #define _OS_TIME_H_
37
38
39 #include "pipe/p_config.h"
40
41 #if defined(PIPE_OS_UNIX)
42 # include <unistd.h> /* usleep */
43 #endif
44
45 #include "pipe/p_compiler.h"
46
47
48 #ifdef __cplusplus
49 extern "C" {
50 #endif
51
52
53 /*
54 * Get the current time in nanoseconds from an unknown base.
55 */
56 int64_t
57 os_time_get_nano(void);
58
59
60 /*
61 * Get the current time in microseconds from an unknown base.
62 */
63 static inline int64_t
os_time_get(void)64 os_time_get(void)
65 {
66 return os_time_get_nano() / 1000;
67 }
68
69
70 /*
71 * Sleep.
72 */
73 void
74 os_time_sleep(int64_t usecs);
75
76
77 /*
78 * Helper function for detecting time outs, taking in account overflow.
79 *
80 * Returns true if the current time has elapsed beyond the specified interval.
81 */
82 static inline boolean
os_time_timeout(int64_t start,int64_t end,int64_t curr)83 os_time_timeout(int64_t start,
84 int64_t end,
85 int64_t curr)
86 {
87 if (start <= end)
88 return !(start <= curr && curr < end);
89 else
90 return !((start <= curr) || (curr < end));
91 }
92
93
94 /**
95 * Convert a relative timeout in nanoseconds into an absolute timeout,
96 * in other words, it returns current time + timeout.
97 * os_time_get_nano() must be monotonic.
98 * PIPE_TIMEOUT_INFINITE is passed through unchanged. If the calculation
99 * overflows, PIPE_TIMEOUT_INFINITE is returned.
100 */
101 int64_t
102 os_time_get_absolute_timeout(uint64_t timeout);
103
104
105 /**
106 * Wait until the variable at the given memory location is zero.
107 *
108 * \param var variable
109 * \param timeout timeout in ns, can be anything from 0 (no wait) to
110 * PIPE_TIME_INFINITE (wait forever)
111 * \return true if the variable is zero
112 */
113 bool
114 os_wait_until_zero(volatile int *var, uint64_t timeout);
115
116
117 /**
118 * Wait until the variable at the given memory location is zero.
119 * The timeout is the absolute time when the waiting should stop. If it is
120 * less than or equal to the current time, it only returns the status and
121 * doesn't wait. PIPE_TIME_INFINITE waits forever. This requires that
122 * os_time_get_nano is monotonic.
123 *
124 * \param var variable
125 * \param timeout the time in ns when the waiting should stop
126 * \return true if the variable is zero
127 */
128 bool
129 os_wait_until_zero_abs_timeout(volatile int *var, int64_t timeout);
130
131 #ifdef __cplusplus
132 }
133 #endif
134
135 #endif /* _OS_TIME_H_ */
136