1 // SPDX-License-Identifier: GPL-2.0-only <<
2 /* 1 /*
3 * This test checks the response of the system 2 * This test checks the response of the system clock to frequency
4 * steps made with adjtimex(). The frequency e 3 * steps made with adjtimex(). The frequency error and stability of
5 * the CLOCK_MONOTONIC clock relative to the C 4 * the CLOCK_MONOTONIC clock relative to the CLOCK_MONOTONIC_RAW clock
6 * is measured in two intervals following the 5 * is measured in two intervals following the step. The test fails if
7 * values from the second interval exceed spec 6 * values from the second interval exceed specified limits.
8 * 7 *
9 * Copyright (C) Miroslav Lichvar <mlichvar@re 8 * Copyright (C) Miroslav Lichvar <mlichvar@redhat.com> 2017
>> 9 *
>> 10 * This program is free software; you can redistribute it and/or modify
>> 11 * it under the terms of version 2 of the GNU General Public License as
>> 12 * published by the Free Software Foundation.
>> 13 *
>> 14 * This program is distributed in the hope that it will be useful, but
>> 15 * WITHOUT ANY WARRANTY; without even the implied warranty of
>> 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
>> 17 * General Public License for more details.
10 */ 18 */
11 19
12 #include <math.h> 20 #include <math.h>
13 #include <stdio.h> 21 #include <stdio.h>
14 #include <sys/timex.h> 22 #include <sys/timex.h>
15 #include <time.h> 23 #include <time.h>
16 #include <unistd.h> 24 #include <unistd.h>
17 25
18 #include "../kselftest.h" 26 #include "../kselftest.h"
19 27
20 #define SAMPLES 100 28 #define SAMPLES 100
21 #define SAMPLE_READINGS 10 29 #define SAMPLE_READINGS 10
22 #define MEAN_SAMPLE_INTERVAL 0.1 30 #define MEAN_SAMPLE_INTERVAL 0.1
23 #define STEP_INTERVAL 1.0 31 #define STEP_INTERVAL 1.0
24 #define MAX_PRECISION 500e-9 !! 32 #define MAX_PRECISION 100e-9
25 #define MAX_FREQ_ERROR 0.02e-6 !! 33 #define MAX_FREQ_ERROR 10e-6
26 #define MAX_STDDEV 50e-9 !! 34 #define MAX_STDDEV 1000e-9
27 <<
28 #ifndef ADJ_SETOFFSET <<
29 #define ADJ_SETOFFSET 0x0100 <<
30 #endif <<
31 35
32 struct sample { 36 struct sample {
33 double offset; 37 double offset;
34 double time; 38 double time;
35 }; 39 };
36 40
37 static time_t mono_raw_base; 41 static time_t mono_raw_base;
38 static time_t mono_base; 42 static time_t mono_base;
39 static long user_hz; 43 static long user_hz;
40 static double precision; 44 static double precision;
41 static double mono_freq_offset; 45 static double mono_freq_offset;
42 46
43 static double diff_timespec(struct timespec *t 47 static double diff_timespec(struct timespec *ts1, struct timespec *ts2)
44 { 48 {
45 return ts1->tv_sec - ts2->tv_sec + (ts 49 return ts1->tv_sec - ts2->tv_sec + (ts1->tv_nsec - ts2->tv_nsec) / 1e9;
46 } 50 }
47 51
48 static double get_sample(struct sample *sample 52 static double get_sample(struct sample *sample)
49 { 53 {
50 double delay, mindelay = 0.0; 54 double delay, mindelay = 0.0;
51 struct timespec ts1, ts2, ts3; 55 struct timespec ts1, ts2, ts3;
52 int i; 56 int i;
53 57
54 for (i = 0; i < SAMPLE_READINGS; i++) 58 for (i = 0; i < SAMPLE_READINGS; i++) {
55 clock_gettime(CLOCK_MONOTONIC_ 59 clock_gettime(CLOCK_MONOTONIC_RAW, &ts1);
56 clock_gettime(CLOCK_MONOTONIC, 60 clock_gettime(CLOCK_MONOTONIC, &ts2);
57 clock_gettime(CLOCK_MONOTONIC_ 61 clock_gettime(CLOCK_MONOTONIC_RAW, &ts3);
58 62
59 ts1.tv_sec -= mono_raw_base; 63 ts1.tv_sec -= mono_raw_base;
60 ts2.tv_sec -= mono_base; 64 ts2.tv_sec -= mono_base;
61 ts3.tv_sec -= mono_raw_base; 65 ts3.tv_sec -= mono_raw_base;
62 66
63 delay = diff_timespec(&ts3, &t 67 delay = diff_timespec(&ts3, &ts1);
64 if (delay <= 1e-9) { 68 if (delay <= 1e-9) {
65 i--; 69 i--;
66 continue; 70 continue;
67 } 71 }
68 72
69 if (!i || delay < mindelay) { 73 if (!i || delay < mindelay) {
70 sample->offset = diff_ 74 sample->offset = diff_timespec(&ts2, &ts1);
71 sample->offset -= dela 75 sample->offset -= delay / 2.0;
72 sample->time = ts1.tv_ 76 sample->time = ts1.tv_sec + ts1.tv_nsec / 1e9;
73 mindelay = delay; 77 mindelay = delay;
74 } 78 }
75 } 79 }
76 80
77 return mindelay; 81 return mindelay;
78 } 82 }
79 83
80 static void reset_ntp_error(void) 84 static void reset_ntp_error(void)
81 { 85 {
82 struct timex txc; 86 struct timex txc;
83 87
84 txc.modes = ADJ_SETOFFSET; 88 txc.modes = ADJ_SETOFFSET;
85 txc.time.tv_sec = 0; 89 txc.time.tv_sec = 0;
86 txc.time.tv_usec = 0; 90 txc.time.tv_usec = 0;
87 91
88 if (adjtimex(&txc) < 0) { 92 if (adjtimex(&txc) < 0) {
89 perror("[FAIL] adjtimex"); 93 perror("[FAIL] adjtimex");
90 ksft_exit_fail(); 94 ksft_exit_fail();
91 } 95 }
92 } 96 }
93 97
94 static void set_frequency(double freq) 98 static void set_frequency(double freq)
95 { 99 {
96 struct timex txc; 100 struct timex txc;
97 int tick_offset; 101 int tick_offset;
98 102
99 tick_offset = 1e6 * freq / user_hz; 103 tick_offset = 1e6 * freq / user_hz;
100 104
101 txc.modes = ADJ_TICK | ADJ_FREQUENCY; 105 txc.modes = ADJ_TICK | ADJ_FREQUENCY;
102 txc.tick = 1000000 / user_hz + tick_of 106 txc.tick = 1000000 / user_hz + tick_offset;
103 txc.freq = (1e6 * freq - user_hz * tic 107 txc.freq = (1e6 * freq - user_hz * tick_offset) * (1 << 16);
104 108
105 if (adjtimex(&txc) < 0) { 109 if (adjtimex(&txc) < 0) {
106 perror("[FAIL] adjtimex"); 110 perror("[FAIL] adjtimex");
107 ksft_exit_fail(); 111 ksft_exit_fail();
108 } 112 }
109 } 113 }
110 114
111 static void regress(struct sample *samples, in 115 static void regress(struct sample *samples, int n, double *intercept,
112 double *slope, double *r_s 116 double *slope, double *r_stddev, double *r_max)
113 { 117 {
114 double x, y, r, x_sum, y_sum, xy_sum, 118 double x, y, r, x_sum, y_sum, xy_sum, x2_sum, r2_sum;
115 int i; 119 int i;
116 120
117 x_sum = 0.0, y_sum = 0.0, xy_sum = 0.0 121 x_sum = 0.0, y_sum = 0.0, xy_sum = 0.0, x2_sum = 0.0;
118 122
119 for (i = 0; i < n; i++) { 123 for (i = 0; i < n; i++) {
120 x = samples[i].time; 124 x = samples[i].time;
121 y = samples[i].offset; 125 y = samples[i].offset;
122 126
123 x_sum += x; 127 x_sum += x;
124 y_sum += y; 128 y_sum += y;
125 xy_sum += x * y; 129 xy_sum += x * y;
126 x2_sum += x * x; 130 x2_sum += x * x;
127 } 131 }
128 132
129 *slope = (xy_sum - x_sum * y_sum / n) 133 *slope = (xy_sum - x_sum * y_sum / n) / (x2_sum - x_sum * x_sum / n);
130 *intercept = (y_sum - *slope * x_sum) 134 *intercept = (y_sum - *slope * x_sum) / n;
131 135
132 *r_max = 0.0, r2_sum = 0.0; 136 *r_max = 0.0, r2_sum = 0.0;
133 137
134 for (i = 0; i < n; i++) { 138 for (i = 0; i < n; i++) {
135 x = samples[i].time; 139 x = samples[i].time;
136 y = samples[i].offset; 140 y = samples[i].offset;
137 r = fabs(x * *slope + *interce 141 r = fabs(x * *slope + *intercept - y);
138 if (*r_max < r) 142 if (*r_max < r)
139 *r_max = r; 143 *r_max = r;
140 r2_sum += r * r; 144 r2_sum += r * r;
141 } 145 }
142 146
143 *r_stddev = sqrt(r2_sum / n); 147 *r_stddev = sqrt(r2_sum / n);
144 } 148 }
145 149
146 static int run_test(int calibration, double fr 150 static int run_test(int calibration, double freq_base, double freq_step)
147 { 151 {
148 struct sample samples[SAMPLES]; 152 struct sample samples[SAMPLES];
149 double intercept, slope, stddev1, max1 153 double intercept, slope, stddev1, max1, stddev2, max2;
150 double freq_error1, freq_error2; 154 double freq_error1, freq_error2;
151 int i; 155 int i;
152 156
153 set_frequency(freq_base); 157 set_frequency(freq_base);
154 158
155 for (i = 0; i < 10; i++) 159 for (i = 0; i < 10; i++)
156 usleep(1e6 * MEAN_SAMPLE_INTER 160 usleep(1e6 * MEAN_SAMPLE_INTERVAL / 10);
157 161
158 reset_ntp_error(); 162 reset_ntp_error();
159 163
160 set_frequency(freq_base + freq_step); 164 set_frequency(freq_base + freq_step);
161 165
162 for (i = 0; i < 10; i++) 166 for (i = 0; i < 10; i++)
163 usleep(rand() % 2000000 * STEP 167 usleep(rand() % 2000000 * STEP_INTERVAL / 10);
164 168
165 set_frequency(freq_base); 169 set_frequency(freq_base);
166 170
167 for (i = 0; i < SAMPLES; i++) { 171 for (i = 0; i < SAMPLES; i++) {
168 usleep(rand() % 2000000 * MEAN 172 usleep(rand() % 2000000 * MEAN_SAMPLE_INTERVAL);
169 get_sample(&samples[i]); 173 get_sample(&samples[i]);
170 } 174 }
171 175
172 if (calibration) { 176 if (calibration) {
173 regress(samples, SAMPLES, &int 177 regress(samples, SAMPLES, &intercept, &slope, &stddev1, &max1);
174 mono_freq_offset = slope; 178 mono_freq_offset = slope;
175 printf("CLOCK_MONOTONIC_RAW fr 179 printf("CLOCK_MONOTONIC_RAW frequency offset: %11.3f ppm\n",
176 1e6 * mono_freq_offset) 180 1e6 * mono_freq_offset);
177 return 0; 181 return 0;
178 } 182 }
179 183
180 regress(samples, SAMPLES / 2, &interce 184 regress(samples, SAMPLES / 2, &intercept, &slope, &stddev1, &max1);
181 freq_error1 = slope * (1.0 - mono_freq 185 freq_error1 = slope * (1.0 - mono_freq_offset) - mono_freq_offset -
182 freq_base; 186 freq_base;
183 187
184 regress(samples + SAMPLES / 2, SAMPLES 188 regress(samples + SAMPLES / 2, SAMPLES / 2, &intercept, &slope,
185 &stddev2, &max2); 189 &stddev2, &max2);
186 freq_error2 = slope * (1.0 - mono_freq 190 freq_error2 = slope * (1.0 - mono_freq_offset) - mono_freq_offset -
187 freq_base; 191 freq_base;
188 192
189 printf("%6.0f %+10.3f %6.0f %7.0f %+10 193 printf("%6.0f %+10.3f %6.0f %7.0f %+10.3f %6.0f %7.0f\t",
190 1e6 * freq_step, 194 1e6 * freq_step,
191 1e6 * freq_error1, 1e9 * stddev 195 1e6 * freq_error1, 1e9 * stddev1, 1e9 * max1,
192 1e6 * freq_error2, 1e9 * stddev 196 1e6 * freq_error2, 1e9 * stddev2, 1e9 * max2);
193 197
194 if (fabs(freq_error2) > MAX_FREQ_ERROR 198 if (fabs(freq_error2) > MAX_FREQ_ERROR || stddev2 > MAX_STDDEV) {
195 printf("[FAIL]\n"); 199 printf("[FAIL]\n");
196 return 1; 200 return 1;
197 } 201 }
198 202
199 printf("[OK]\n"); 203 printf("[OK]\n");
200 return 0; 204 return 0;
201 } 205 }
202 206
203 static void init_test(void) 207 static void init_test(void)
204 { 208 {
205 struct timespec ts; 209 struct timespec ts;
206 struct sample sample; 210 struct sample sample;
207 211
208 if (clock_gettime(CLOCK_MONOTONIC_RAW, 212 if (clock_gettime(CLOCK_MONOTONIC_RAW, &ts)) {
209 perror("[FAIL] clock_gettime(C 213 perror("[FAIL] clock_gettime(CLOCK_MONOTONIC_RAW)");
210 ksft_exit_fail(); 214 ksft_exit_fail();
211 } 215 }
212 216
213 mono_raw_base = ts.tv_sec; 217 mono_raw_base = ts.tv_sec;
214 218
215 if (clock_gettime(CLOCK_MONOTONIC, &ts 219 if (clock_gettime(CLOCK_MONOTONIC, &ts)) {
216 perror("[FAIL] clock_gettime(C 220 perror("[FAIL] clock_gettime(CLOCK_MONOTONIC)");
217 ksft_exit_fail(); 221 ksft_exit_fail();
218 } 222 }
219 223
220 mono_base = ts.tv_sec; 224 mono_base = ts.tv_sec;
221 225
222 user_hz = sysconf(_SC_CLK_TCK); 226 user_hz = sysconf(_SC_CLK_TCK);
223 227
224 precision = get_sample(&sample) / 2.0; 228 precision = get_sample(&sample) / 2.0;
225 printf("CLOCK_MONOTONIC_RAW+CLOCK_MONO 229 printf("CLOCK_MONOTONIC_RAW+CLOCK_MONOTONIC precision: %.0f ns\t\t",
226 1e9 * precision); 230 1e9 * precision);
227 231
228 if (precision > MAX_PRECISION) 232 if (precision > MAX_PRECISION)
229 ksft_exit_skip("precision: %.0 233 ksft_exit_skip("precision: %.0f ns > MAX_PRECISION: %.0f ns\n",
230 1e9 * precisio 234 1e9 * precision, 1e9 * MAX_PRECISION);
231 235
232 printf("[OK]\n"); 236 printf("[OK]\n");
233 srand(ts.tv_sec ^ ts.tv_nsec); 237 srand(ts.tv_sec ^ ts.tv_nsec);
234 238
235 run_test(1, 0.0, 0.0); 239 run_test(1, 0.0, 0.0);
236 } 240 }
237 241
238 int main(int argc, char **argv) 242 int main(int argc, char **argv)
239 { 243 {
240 double freq_base, freq_step; 244 double freq_base, freq_step;
241 int i, j, fails = 0; 245 int i, j, fails = 0;
242 246
243 init_test(); 247 init_test();
244 248
245 printf("Checking response to frequency 249 printf("Checking response to frequency step:\n");
246 printf(" Step 1st interval 250 printf(" Step 1st interval 2nd interval\n");
247 printf(" Freq Dev M 251 printf(" Freq Dev Max Freq Dev Max\n");
248 252
249 for (i = 2; i >= 0; i--) { 253 for (i = 2; i >= 0; i--) {
250 for (j = 0; j < 5; j++) { 254 for (j = 0; j < 5; j++) {
251 freq_base = (rand() % 255 freq_base = (rand() % (1 << 24) - (1 << 23)) / 65536e6;
252 freq_step = 10e-6 * (1 256 freq_step = 10e-6 * (1 << (6 * i));
253 fails += run_test(0, f 257 fails += run_test(0, freq_base, freq_step);
254 } 258 }
255 } 259 }
256 260
257 set_frequency(0.0); 261 set_frequency(0.0);
258 262
259 if (fails) 263 if (fails)
260 ksft_exit_fail(); 264 ksft_exit_fail();
261 265
262 ksft_exit_pass(); 266 ksft_exit_pass();
263 } 267 }
264 268
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