1 /*
2 * Copyright (c) 2014 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 clock_gettime(). Use the kpmap after the 10th call.
37 */
38
39 #include <sys/cdefs.h>
40 #include <sys/types.h>
41 #include <sys/syscall.h>
42 #include <sys/upmap.h>
43 #include <sys/time.h>
44 #include <machine/cpufunc.h>
45 #include <errno.h>
46 #include <time.h>
47 #include <stdio.h>
48 #include <unistd.h>
49 /*#include "un-namespace.h"*/
50 #include "libc_private.h"
51 #include "upmap.h"
52
53 extern int __sys_clock_gettime(clockid_t clock_id, struct timespec *ts);
54 int __clock_gettime(clockid_t clock_id, struct timespec *ts);
55
56 static int fast_clock;
57 static int fast_count;
58 static int *upticksp;
59 static struct timespec *ts_uptime;
60 static struct timespec *ts_realtime;
61
62 int
__clock_gettime(clockid_t clock_id,struct timespec * ts)63 __clock_gettime(clockid_t clock_id, struct timespec *ts)
64 {
65 int res;
66 int w;
67
68 if (fast_clock == 0 && fast_count++ >= 10) {
69 __kpmap_map(&upticksp, &fast_clock, KPTYPE_UPTICKS);
70 __kpmap_map(&ts_uptime, &fast_clock, KPTYPE_TS_UPTIME);
71 __kpmap_map(&ts_realtime, &fast_clock, KPTYPE_TS_REALTIME);
72 __kpmap_map(NULL, &fast_clock, 0);
73 }
74 if (fast_clock > 0) {
75 switch(clock_id) {
76 case CLOCK_UPTIME_FAST:
77 case CLOCK_MONOTONIC_FAST:
78 do {
79 w = *upticksp;
80 cpu_lfence();
81 *ts = ts_uptime[w & 1];
82 cpu_lfence();
83 w = *upticksp - w;
84 } while (w > 1);
85 res = 0;
86 break;
87 case CLOCK_REALTIME_FAST:
88 case CLOCK_SECOND:
89 do {
90 w = *upticksp;
91 cpu_lfence();
92 *ts = ts_realtime[w & 1];
93 cpu_lfence();
94 w = *upticksp - w;
95 } while (w > 1);
96
97 if (clock_id == CLOCK_SECOND)
98 ts->tv_nsec = 0;
99 res = 0;
100 break;
101 default:
102 res = __sys_clock_gettime(clock_id, ts);
103 break;
104 }
105 } else {
106 res = __sys_clock_gettime(clock_id, ts);
107 }
108 return res;
109 }
110
111 __weak_reference(__clock_gettime, clock_gettime);
112