2 * Copyright (c) 2008, 2009, 2010, 2011, 2012 Nicira, Inc.
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at:
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
21 #include "type-props.h"
32 /* POSIX allows floating-point time_t, but we don't support it. */
33 BUILD_ASSERT_DECL(TYPE_IS_INTEGER(time_t));
35 /* We do try to cater to unsigned time_t, but I want to know about it if we
36 * ever encounter such a platform. */
37 BUILD_ASSERT_DECL(TYPE_IS_SIGNED(time_t));
39 /* On x86-64 systems, Linux avoids using syscalls for clock_gettime().
41 * For systems which do invoke a system call we wait at least
42 * TIME_UPDATE_INTERVAL ms between clock_gettime() calls and cache the time for
45 * For systems which do not invoke a system call, we just call clock_gettime()
46 * whenever the time is requested. As a result we don't start the background
47 * SIGALRM timer unless explicitly needed by time_alarm() */
48 #if defined __x86_64__ && defined __linux__
54 #define TIME_MAX TYPE_MAXIMUM(time_t)
55 #define TIME_MIN TYPE_MINIMUM(time_t)
57 /* Interval between updates to the reported time, in ms. This should not be
58 * adjusted much below 10 ms or so with the current implementation, or too
59 * much time will be wasted in signal handlers and calls to clock_gettime(). */
60 #define TIME_UPDATE_INTERVAL 100
62 void time_disable_restart(void);
63 void time_enable_restart(void);
64 void time_postfork(void);
65 void time_refresh(void);
66 time_t time_now(void);
67 time_t time_wall(void);
68 long long int time_msec(void);
69 long long int time_wall_msec(void);
70 void time_timespec(struct timespec *);
71 void time_wall_timespec(struct timespec *);
72 void time_alarm(unsigned int secs);
73 int time_poll(struct pollfd *, int n_pollfds, long long int timeout_when,
76 long long int timespec_to_msec(const struct timespec *);
77 long long int timeval_to_msec(const struct timeval *);
79 void xgettimeofday(struct timeval *);
81 int get_cpu_usage(void);
83 long long int time_boot_msec(void);
89 #endif /* timeval.h */