linuxdebug/tools/testing/selftests/timers/skew_consistency.c

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2024-07-16 15:50:57 +02:00
/* ADJ_FREQ Skew consistency test
* by: john stultz (johnstul@us.ibm.com)
* (C) Copyright IBM 2012
* Licensed under the GPLv2
*
* NOTE: This is a meta-test which cranks the ADJ_FREQ knob back
* and forth and watches for consistency problems. Thus this test requires
* that the inconsistency-check tests be present in the same directory it
* is run from.
*
* To build:
* $ gcc skew_consistency.c -o skew_consistency -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 <stdlib.h>
#include <unistd.h>
#include <sys/time.h>
#include <sys/timex.h>
#include <time.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <string.h>
#include <sys/wait.h>
#include "../kselftest.h"
#define NSEC_PER_SEC 1000000000LL
int main(int argc, char **argv)
{
struct timex tx;
int ret, ppm;
pid_t pid;
printf("Running Asynchronous Frequency Changing Tests...\n");
pid = fork();
if (!pid)
return system("./inconsistency-check -c 1 -t 600");
ppm = 500;
ret = 0;
while (pid != waitpid(pid, &ret, WNOHANG)) {
ppm = -ppm;
tx.modes = ADJ_FREQUENCY;
tx.freq = ppm << 16;
adjtimex(&tx);
usleep(500000);
}
/* Set things back */
tx.modes = ADJ_FREQUENCY;
tx.offset = 0;
adjtimex(&tx);
if (ret) {
printf("[FAILED]\n");
return ksft_exit_fail();
}
printf("[OK]\n");
return ksft_exit_pass();
}