1 /*
2 * Copyright (c) 2018 The DragonFly Project. All rights reserved.
3 *
4 * This code is derived from software contributed to The DragonFly Project
5 * by Matthew Dillon <dillon@backplane.com>
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 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. 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 * 3. Neither the name of The DragonFly Project 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
24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 /*
36 * UKP-Optimized gettimeofday(). Use the kpmap after the 10th call.
37 */
38 #include <sys/cdefs.h>
39 #include <sys/types.h>
40 #include <sys/syscall.h>
41 #include <sys/upmap.h>
42 #include <sys/time.h>
43 #include <machine/cpufunc.h>
44 #include <errno.h>
45 #include <time.h>
46 #include <stdio.h>
47 #include <unistd.h>
48 /*#include "un-namespace.h"*/
49 #include "libc_private.h"
50 #include "upmap.h"
51
52 extern int __sys_gettimeofday(struct timeval *, struct timezone *);
53 int __gettimeofday(struct timeval *, struct timezone *);
54
55 static int fast_clock;
56 static int fast_count;
57 static int *fast_gtod;
58 static int *upticksp;
59 static struct timespec *ts_realtime;
60
61 #ifdef KPTYPE_FAST_GTOD
62 int
__gettimeofday(struct timeval * tv,struct timezone * tz)63 __gettimeofday(struct timeval *tv, struct timezone *tz)
64 {
65 struct timespec ts;
66 int res;
67 int w;
68
69 if (fast_clock == 0 && fast_count++ >= 10) {
70 __kpmap_map(&upticksp, &fast_clock, KPTYPE_UPTICKS);
71 __kpmap_map(&ts_realtime, &fast_clock, KPTYPE_TS_REALTIME);
72 __kpmap_map(&fast_gtod, &fast_clock, KPTYPE_FAST_GTOD);
73 __kpmap_map(NULL, &fast_clock, 0);
74 }
75 if (fast_clock > 0 && *fast_gtod && tz == NULL) {
76 do {
77 w = *upticksp;
78 cpu_lfence();
79 ts = ts_realtime[w & 1];
80 cpu_lfence();
81 w = *upticksp - w;
82 } while (w > 1);
83 res = 0;
84 if (tv) {
85 tv->tv_sec = ts.tv_sec;
86 tv->tv_usec = ts.tv_nsec / 1000;
87 }
88 } else {
89 res = __sys_gettimeofday(tv, tz);
90 }
91 return res;
92 }
93
94 #else
95
96 int
__gettimeofday(struct timeval * tv,struct timezone * tz)97 __gettimeofday(struct timeval *tv, struct timezone *tz)
98 {
99 int res;
100
101 res = __sys_gettimeofday(tv, tz);
102 return res;
103 }
104
105 #endif
106
107 __weak_reference(__gettimeofday, gettimeofday);
108