Author | Tokens | Token Proportion | Commits | Commit Proportion |
---|---|---|---|---|
John Stultz | 770 | 98.84% | 1 | 25.00% |
Kees Cook | 5 | 0.64% | 1 | 25.00% |
Wolfram Sang | 2 | 0.26% | 1 | 25.00% |
Nathan Chancellor | 2 | 0.26% | 1 | 25.00% |
Total | 779 | 4 |
/* adjtimex() tick adjustment test * by: John Stultz <john.stultz@linaro.org> * (C) Copyright Linaro Limited 2015 * Licensed under the GPLv2 * * To build: * $ gcc adjtick.c -o adjtick -lrt * * This program is free software: you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation, either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <sys/time.h> #include <sys/timex.h> #include <time.h> #include "../kselftest.h" #define CLOCK_MONOTONIC_RAW 4 #define NSEC_PER_SEC 1000000000LL #define USEC_PER_SEC 1000000 #define MILLION 1000000 long systick; long long llabs(long long val) { if (val < 0) val = -val; return val; } unsigned long long ts_to_nsec(struct timespec ts) { return ts.tv_sec * NSEC_PER_SEC + ts.tv_nsec; } struct timespec nsec_to_ts(long long ns) { struct timespec ts; ts.tv_sec = ns/NSEC_PER_SEC; ts.tv_nsec = ns%NSEC_PER_SEC; return ts; } long long diff_timespec(struct timespec start, struct timespec end) { long long start_ns, end_ns; start_ns = ts_to_nsec(start); end_ns = ts_to_nsec(end); return end_ns - start_ns; } void get_monotonic_and_raw(struct timespec *mon, struct timespec *raw) { struct timespec start, mid, end; long long diff = 0, tmp; int i; clock_gettime(CLOCK_MONOTONIC, mon); clock_gettime(CLOCK_MONOTONIC_RAW, raw); /* Try to get a more tightly bound pairing */ for (i = 0; i < 3; i++) { long long newdiff; clock_gettime(CLOCK_MONOTONIC, &start); clock_gettime(CLOCK_MONOTONIC_RAW, &mid); clock_gettime(CLOCK_MONOTONIC, &end); newdiff = diff_timespec(start, end); if (diff == 0 || newdiff < diff) { diff = newdiff; *raw = mid; tmp = (ts_to_nsec(start) + ts_to_nsec(end))/2; *mon = nsec_to_ts(tmp); } } } long long get_ppm_drift(void) { struct timespec mon_start, raw_start, mon_end, raw_end; long long delta1, delta2, eppm; get_monotonic_and_raw(&mon_start, &raw_start); sleep(15); get_monotonic_and_raw(&mon_end, &raw_end); delta1 = diff_timespec(mon_start, mon_end); delta2 = diff_timespec(raw_start, raw_end); eppm = (delta1*MILLION)/delta2 - MILLION; return eppm; } int check_tick_adj(long tickval) { long long eppm, ppm; struct timex tx1; tx1.modes = ADJ_TICK; tx1.modes |= ADJ_OFFSET; tx1.modes |= ADJ_FREQUENCY; tx1.modes |= ADJ_STATUS; tx1.status = STA_PLL; tx1.offset = 0; tx1.freq = 0; tx1.tick = tickval; adjtimex(&tx1); sleep(1); ppm = ((long long)tickval * MILLION)/systick - MILLION; printf("Estimating tick (act: %ld usec, %lld ppm): ", tickval, ppm); eppm = get_ppm_drift(); printf("%lld usec, %lld ppm", systick + (systick * eppm / MILLION), eppm); fflush(stdout); tx1.modes = 0; adjtimex(&tx1); if (tx1.offset || tx1.freq || tx1.tick != tickval) { printf(" [ERROR]\n"); printf("\tUnexpected adjtimex return values, make sure ntpd is not running.\n"); return -1; } /* * Here we use 100ppm difference as an error bound. * We likely should see better, but some coarse clocksources * cannot match the HZ tick size accurately, so we have a * internal correction factor that doesn't scale exactly * with the adjustment, resulting in > 10ppm error during * a 10% adjustment. 100ppm also gives us more breathing * room for interruptions during the measurement. */ if (llabs(eppm - ppm) > 100) { printf(" [FAILED]\n"); return -1; } printf(" [OK]\n"); return 0; } int main(int argc, char **argv) { struct timespec raw; long tick, max, interval, err; struct timex tx1; err = 0; setbuf(stdout, NULL); if (clock_gettime(CLOCK_MONOTONIC_RAW, &raw)) { printf("ERR: NO CLOCK_MONOTONIC_RAW\n"); return -1; } printf("Each iteration takes about 15 seconds\n"); systick = sysconf(_SC_CLK_TCK); systick = USEC_PER_SEC/sysconf(_SC_CLK_TCK); max = systick/10; /* +/- 10% */ interval = max/4; /* in 4 steps each side */ for (tick = (systick - max); tick < (systick + max); tick += interval) { if (check_tick_adj(tick)) { err = 1; break; } } /* Reset things to zero */ tx1.modes = ADJ_TICK; tx1.modes |= ADJ_OFFSET; tx1.modes |= ADJ_FREQUENCY; tx1.offset = 0; tx1.freq = 0; tx1.tick = systick; adjtimex(&tx1); if (err) ksft_exit_fail(); ksft_exit_pass(); }
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