1 /*------------------------------------------------------------------------------
2 *
3 * Copyright (c) 2011-2021, EURid vzw. All rights reserved.
4 * The YADIFA TM software product is provided under the BSD 3-clause license:
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * * Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * * Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * * Neither the name of EURid nor the names of its contributors may be
16 * used to endorse or promote products derived from this software
17 * without specific prior written permission.
18 *
19 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
20 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
23 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
29 * POSSIBILITY OF SUCH DAMAGE.
30 *
31 *------------------------------------------------------------------------------
32 *
33 */
34
35 #include "dnscore/dnscore-config.h"
36 #include <unistd.h>
37
38 #include "dnscore/logger.h"
39 #include "dnscore/pace.h"
40
41 extern logger_handle *g_system_logger;
42 #define MODULE_MSG_HANDLE g_system_logger
43
44 #define PACE_DUMP 0
45
46 #define PACE_MODE_SMOOTH 0
47 #define PACE_MODE_HARD 1
48
49 #define PACE_MODE PACE_MODE_HARD
50
51 void
pace_init(pace_s * pace,u64 min_us,u64 max_us,const char * name)52 pace_init(pace_s *pace, u64 min_us, u64 max_us, const char *name)
53 {
54 if(min_us > max_us)
55 {
56 u64 tmp = max_us;
57 max_us = min_us;
58 min_us = tmp;
59 }
60
61 pace->min_us = min_us;
62 pace->max_us = max_us;
63 #if PACE_MODE == PACE_MODE_SMOOTH
64 pace->current_us = (max_us + min_us) >> 1;
65 #else
66 pace->current_us = min_us;
67 #endif
68 pace->counter = 0;
69
70 pace->name = name;
71 }
72
73 /**
74 * Will pause for a while
75 */
76
77 void
pace_wait(pace_s * pace)78 pace_wait(pace_s *pace)
79 {
80 u64 start = timeus();
81
82 if((pace->counter > 0) && ((pace->counter & 3) != 0))
83 {
84 #if defined(PACE_DUMP) && (PACE_DUMP > 0)
85 u64 current = pace->current_us;
86 #endif
87 pace->current_us <<= 1;
88
89 if(pace->current_us == 0)
90 {
91 pace->current_us = 1;
92 }
93
94 if(pace->current_us > pace->max_us)
95 {
96 pace->current_us = pace->max_us;
97 }
98
99 #if defined(PACE_DUMP) && (PACE_DUMP > 0)
100 if(current != pace->current_us)
101 {
102 log_debug("pace: '%s' waiting for %lluµs (#%llu)", pace->name, pace->current_us, pace->counter);
103 }
104 #endif
105 }
106 else
107 {
108 pace->wait_start = start;
109
110 #if defined(PACE_DUMP) && (PACE_DUMP > 0)
111 log_debug("pace: '%s' waiting for %lluµs (#%llu)", pace->name, pace->current_us, pace->counter);
112 #endif
113 }
114
115 pace->counter++;
116
117 u64 elapsed = 0;
118 u64 current = pace->current_us;
119 do
120 {
121 if(elapsed > current)
122 {
123 log_err("pace_wait: impossible! elapsed = %llu > %llu", elapsed, current);
124 break;
125 }
126
127 usleep(current - elapsed);
128 u64 now = timeus();
129
130 if(now < start)
131 {
132 log_err("pace_wait: now=%llu < start=%llu (%llu)", now, start, start-now);
133 break;
134 }
135 elapsed = now - start;
136 }
137 while(elapsed < current);
138 }
139
140 /**
141 * Will update the pace taking the fact that now we have work to do
142 */
143
144 void
pace_work(pace_s * pace)145 pace_work(pace_s *pace)
146 {
147 pace->wait_end = timeus();
148
149 #if defined(PACE_DUMP) && (PACE_DUMP > 0)
150 log_debug("pace: '%s' working after %lluµs (%lluµs #%llu)",
151 pace->name, pace->wait_end - pace->wait_start, pace->current_us, pace->counter);
152 #endif
153
154 pace->counter = 0;
155 #if PACE_MODE == PACE_MODE_SMOOTH
156 pace->current_us >>= 1;
157 if(pace->current_us < pace->min_us)
158 {
159 pace->current_us = pace->min_us;
160 }
161 #else
162 pace->current_us = pace->min_us;
163 #endif
164 }
165