os_time.c revision 01e04c3f 
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3 * Copyright 2008-2010 VMware, Inc.
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27
28/**
29 * @file
30 * OS independent time-manipulation functions.
31 *
32 * @author Jose Fonseca <jfonseca@vmware.com>
33 */
34
35#include "os_time.h"
36
37/* TODO: fix this dependency */
38#include "gallium/include/pipe/p_config.h"
39
40#include "util/u_atomic.h"
41
42#if defined(PIPE_OS_UNIX)
43#  include <unistd.h> /* usleep */
44#  include <time.h> /* timeval */
45#  include <sys/time.h> /* timeval */
46#  include <sched.h> /* sched_yield */
47#  include <errno.h>
48#elif defined(PIPE_SUBSYSTEM_WINDOWS_USER)
49#  include <windows.h>
50#else
51#  error Unsupported OS
52#endif
53
54
55int64_t
56os_time_get_nano(void)
57{
58#if defined(PIPE_OS_LINUX) || defined(PIPE_OS_BSD)
59
60   struct timespec tv;
61   clock_gettime(CLOCK_MONOTONIC, &tv);
62   return tv.tv_nsec + tv.tv_sec*INT64_C(1000000000);
63
64#elif defined(PIPE_OS_UNIX)
65
66   struct timeval tv;
67   gettimeofday(&tv, NULL);
68   return tv.tv_usec*INT64_C(1000) + tv.tv_sec*INT64_C(1000000000);
69
70#elif defined(PIPE_SUBSYSTEM_WINDOWS_USER)
71
72   static LARGE_INTEGER frequency;
73   LARGE_INTEGER counter;
74   int64_t secs, nanosecs;
75   if(!frequency.QuadPart)
76      QueryPerformanceFrequency(&frequency);
77   QueryPerformanceCounter(&counter);
78   /* Compute seconds and nanoseconds parts separately to
79    * reduce severity of precision loss.
80    */
81   secs = counter.QuadPart / frequency.QuadPart;
82   nanosecs = (counter.QuadPart % frequency.QuadPart) * INT64_C(1000000000)
83      / frequency.QuadPart;
84   return secs*INT64_C(1000000000) + nanosecs;
85
86#else
87
88#error Unsupported OS
89
90#endif
91}
92
93
94
95void
96os_time_sleep(int64_t usecs)
97{
98#if defined(PIPE_OS_LINUX)
99   struct timespec time;
100   time.tv_sec = usecs / 1000000;
101   time.tv_nsec = (usecs % 1000000) * 1000;
102   while (clock_nanosleep(CLOCK_MONOTONIC, 0, &time, &time) == EINTR);
103
104#elif defined(PIPE_OS_UNIX)
105   usleep(usecs);
106
107#elif defined(PIPE_SUBSYSTEM_WINDOWS_USER)
108   DWORD dwMilliseconds = (DWORD) ((usecs + 999) / 1000);
109   /* Avoid Sleep(O) as that would cause to sleep for an undetermined duration */
110   if (dwMilliseconds) {
111      Sleep(dwMilliseconds);
112   }
113#else
114#  error Unsupported OS
115#endif
116}
117
118
119
120int64_t
121os_time_get_absolute_timeout(uint64_t timeout)
122{
123   int64_t time, abs_timeout;
124
125   /* Also check for the type upper bound. */
126   if (timeout == OS_TIMEOUT_INFINITE || timeout > INT64_MAX)
127      return OS_TIMEOUT_INFINITE;
128
129   time = os_time_get_nano();
130   abs_timeout = time + (int64_t)timeout;
131
132   /* Check for overflow. */
133   if (abs_timeout < time)
134      return OS_TIMEOUT_INFINITE;
135
136   return abs_timeout;
137}
138
139
140bool
141os_wait_until_zero(volatile int *var, uint64_t timeout)
142{
143   if (!p_atomic_read(var))
144      return true;
145
146   if (!timeout)
147      return false;
148
149   if (timeout == OS_TIMEOUT_INFINITE) {
150      while (p_atomic_read(var)) {
151#if defined(PIPE_OS_UNIX)
152         sched_yield();
153#endif
154      }
155      return true;
156   }
157   else {
158      int64_t start_time = os_time_get_nano();
159      int64_t end_time = start_time + timeout;
160
161      while (p_atomic_read(var)) {
162         if (os_time_timeout(start_time, end_time, os_time_get_nano()))
163            return false;
164
165#if defined(PIPE_OS_UNIX)
166         sched_yield();
167#endif
168      }
169      return true;
170   }
171}
172
173
174bool
175os_wait_until_zero_abs_timeout(volatile int *var, int64_t timeout)
176{
177   if (!p_atomic_read(var))
178      return true;
179
180   if (timeout == OS_TIMEOUT_INFINITE)
181      return os_wait_until_zero(var, OS_TIMEOUT_INFINITE);
182
183   while (p_atomic_read(var)) {
184      if (os_time_get_nano() >= timeout)
185         return false;
186
187#if defined(PIPE_OS_UNIX)
188      sched_yield();
189#endif
190   }
191   return true;
192}
193