xref: /illumos-kvm-cmd/qemu-timer-common.c (revision 4f48eea6)
1 /*
2  * QEMU System Emulator
3  *
4  * Copyright (c) 2003-2008 Fabrice Bellard
5  *
6  * Permission is hereby granted, free of charge, to any person obtaining a copy
7  * of this software and associated documentation files (the "Software"), to deal
8  * in the Software without restriction, including without limitation the rights
9  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10  * copies of the Software, and to permit persons to whom the Software is
11  * furnished to do so, subject to the following conditions:
12  *
13  * The above copyright notice and this permission notice shall be included in
14  * all copies or substantial portions of the Software.
15  *
16  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
22  * THE SOFTWARE.
23  */
24 #include "qemu-timer.h"
25 
26 /***********************************************************/
27 /* real time host monotonic timer */
28 
29 #ifdef _WIN32
30 
31 int64_t clock_freq;
32 
init_get_clock(void)33 static void __attribute__((constructor)) init_get_clock(void)
34 {
35     LARGE_INTEGER freq;
36     int ret;
37     ret = QueryPerformanceFrequency(&freq);
38     if (ret == 0) {
39         fprintf(stderr, "Could not calibrate ticks\n");
40         exit(1);
41     }
42     clock_freq = freq.QuadPart;
43 }
44 
45 #else
46 
47 int use_rt_clock;
48 
init_get_clock(void)49 static void __attribute__((constructor)) init_get_clock(void)
50 {
51     use_rt_clock = 0;
52 #if defined(__linux__) || (defined(__FreeBSD__) && __FreeBSD_version >= 500000) \
53     || defined(__DragonFly__) || defined(__FreeBSD_kernel__) \
54     || defined(__OpenBSD__) || defined (__sun__)
55     {
56         struct timespec ts;
57         if (clock_gettime(CLOCK_MONOTONIC, &ts) == 0) {
58             use_rt_clock = 1;
59         }
60     }
61 #endif
62 }
63 #endif
64