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scheduling_jitter.c
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1 /*******************************************************************************
2 * Copyright (C) 2019 Moxa Inc. All rights reserved.
3 * SPDX-License-Identifier: Apache-2.0
4 *
5 * Scheduling Jitter Sample Application
6 *
7 * Date Author Comment
8 * 2019-04-25 Wanhan Hsieh Created it.
9 ******************************************************************************/
10
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <unistd.h>
46 #include <signal.h>
47 #include <pthread.h>
48 #include <errno.h>
49 #include <sys/time.h>
50 #include <time.h>
51 #include <iothinx/iothinxio.h>
52 #include <sched.h>
53
54 int set_process_priority(int pid, int priority_level)
55 {
56 int rc = 0;
57 int policy;
58 struct sched_param param = { 0 };
59
60 switch (priority_level)
61 {
62 case 1: // medium
63 policy = SCHED_RR;
64 param.sched_priority = 1;
65 break;
66 case 2: // high
67 policy = SCHED_RR;
68 param.sched_priority = 49;
69 break;
70 case 3: // max
71 policy = SCHED_RR;
72 param.sched_priority = 99;
73 break;
74 case 0: // low
75 default:
76 policy = SCHED_OTHER;
77 param.sched_priority = 0;
78 break;
79 }
80 rc = sched_setscheduler(pid, policy, &param);
81 if(rc != 0)
82 {
83 perror("sched_setscheduler");
84 }
85 return rc;
86 }
87
89 int main(int argc, char **const argv)
90 {
91 int32_t rc;
92 uint32_t do_slot = 2;
93 uint8_t do_channel = 0;
94 uint8_t do_mode = DO_MODE_DO;
95 uint32_t do_values = 0;
96 uint32_t test_cnt = 1000;
97 uint32_t cycle_time_us = 10000;
98 uint32_t i;
99 time_t start_time_us, end_time_us;
100 time_t last_start_time_us = 0;
101 int priority_level = 3;
102 int32_t diff_us;
103 int32_t sum_us = 0;
104 int32_t max_us = 0;
105 struct timespec ts;
106
107 while (-1 != (rc = getopt(argc, argv, "c:hn:p:s:t:")))
108 {
109 switch (rc)
110 {
111 case 'c':
112 do_channel = atoi(optarg);
113 break;
114 case 'n':
115 test_cnt = atoi(optarg);
116 break;
117 case 'p':
118 priority_level = atoi(optarg);
119 break;
120 case 's':
121 do_slot = atoi(optarg);
122 break;
123 case 't':
124 cycle_time_us = atoi(optarg);
125 break;
126 case 'h':
127 default:
128 printf("Scheduling jitter sample program.\n\n");
129 printf("Usage: ./scheduling_jitter [OPTIONS]\n\n");
130 printf("Options: \n");
131 printf("\t %-8s Priority level[0-3]. Default level = %d\n", "-p", priority_level);
132 printf("\t %-8s Slot of DO module. Default slot = %d\n", "-s", do_slot);
133 printf("\t %-8s DO channel. Default channel = %d\n", "-c", do_channel);
134 printf("\t %-8s Testing loop count. Default count = %d\n", "-n", test_cnt);
135 printf("\t %-8s Testing loop cycle time (in us). Default time = %d us\n", "-t", cycle_time_us);
136 printf("\n");
137 return 0;
138 }
139 }
140
141 printf("Priority level = %d\n", priority_level);
142 printf("DO slot = %lu\n", do_slot);
143 printf("DO channel = %u\n", do_channel);
144
145 // initialize ioThinx I/O
146 rc = ioThinx_IO_Client_Init();
147 if (rc != IOTHINX_ERR_OK)
148 {
149 printf("ioThinx_IO_Client_Init() = %d\n", rc);
150 return -1;
151 }
152
153 // temporarily set config
154 rc = ioThinx_DO_Config_SetModes(do_slot, do_channel, 1, &do_mode);
155 if (rc != IOTHINX_ERR_OK)
156 {
157 printf("ioThinx_DO_Config_SetModes() = %d\n", rc);
158 return -1;
159 }
160
161 // reload config
162 rc = ioThinx_IO_Config_Reload();
163 if (rc != IOTHINX_ERR_OK)
164 {
165 printf("ioThinx_IO_Config_Reload() = %d\n", rc);
166 return -1;
167 }
168
169 // set process priority
170 set_process_priority(0, priority_level);
171 if (rc != 0)
172 {
173 return -1;
174 }
175
176 printf("Start testing ...\n");
177
178 for (i = 0; i < test_cnt; i++)
179 {
180 // get start time
181 clock_gettime(CLOCK_MONOTONIC, &ts);
182 start_time_us = (ts.tv_sec * 1000000 + ts.tv_nsec / 1000);
183 diff_us = (last_start_time_us == 0) ? 0 : start_time_us - last_start_time_us - cycle_time_us;
184 sum_us += diff_us;
185 max_us = (diff_us > max_us) ? diff_us : max_us;
186 last_start_time_us = start_time_us;
187
188 // do the stuff ...
189 // invert do value
190 if (do_values & (0x1 << do_channel))
191 {
192 do_values &= ~(0x1 << do_channel);
193 }
194 else
195 {
196 do_values |= 0x1 << do_channel;
197 }
198 rc = ioThinx_DO_SetValues(do_slot, do_values);
199 if (rc != IOTHINX_ERR_OK)
200 {
201 printf("ioThinx_DO_SetValues() = %d\n", rc);
202 break;
203 }
204
205 // get end time
206 clock_gettime(CLOCK_MONOTONIC, &ts);
207 end_time_us = (ts.tv_sec * 1000000 + ts.tv_nsec / 1000);
208
209 // calculate sleep time
210 diff_us = cycle_time_us - (end_time_us - start_time_us);
211 ts.tv_sec = 0;
212 ts.tv_nsec = diff_us * 1000;
213
214 // sleep
215 clock_nanosleep(CLOCK_MONOTONIC, 0, &ts, NULL);
216 }
217
218 printf("Done.\n");
219 printf("Scheduling jitter: Avg. = %.1f us, Max = %ld us\n",
220 (float)sum_us / (float)(test_cnt - 1), max_us);
221
222 return 0;
223 }
DO_MODE_DO
#define DO_MODE_DO
Definition: iothinxio.h:289
ioThinx_DO_SetValues
IOTHINX_ERR ioThinx_DO_SetValues(uint32_t slot, uint32_t values)
IOTHINX_ERR_OK
#define IOTHINX_ERR_OK
Definition: iothinxio.h:35
ioThinx_DO_Config_SetModes
IOTHINX_ERR ioThinx_DO_Config_SetModes(uint32_t slot, uint8_t start, uint8_t count, uint8_t buf[])
ioThinx_IO_Config_Reload
IOTHINX_ERR ioThinx_IO_Config_Reload(void)
main
int main(int argc, char **const argv)
Definition: uart.c:55
ioThinx_IO_Client_Init
IOTHINX_ERR ioThinx_IO_Client_Init(void)