linux_dsm_epyc7002/tools/testing/selftests/timers/mqueue-lat.c
Shuah Khan b841065043 selftests: timers: drop support for !KTEST case
There is no need to keep timers tests in sync with external timers
repo. Drop support for !KTEST to support for building and running
timers tests without kselftest framework.

Reference: https://lkml.org/lkml/2017/8/10/952
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Acked-by: John Stultz <john.stultz@linaro.org>
2017-08-22 11:15:59 -06:00

114 lines
2.6 KiB
C

/* Measure mqueue timeout latency
* by: john stultz (john.stultz@linaro.org)
* (C) Copyright Linaro 2013
*
* Inspired with permission from example test by:
* Romain Francoise <romain@orebokech.com>
* Licensed under the GPLv2
*
* To build:
* $ gcc mqueue-lat.c -o mqueue-lat -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 <time.h>
#include <sys/time.h>
#include <sys/timex.h>
#include <string.h>
#include <signal.h>
#include <errno.h>
#include <mqueue.h>
#include "../kselftest.h"
#define NSEC_PER_SEC 1000000000ULL
#define TARGET_TIMEOUT 100000000 /* 100ms in nanoseconds */
#define UNRESONABLE_LATENCY 40000000 /* 40ms in nanosecs */
long long timespec_sub(struct timespec a, struct timespec b)
{
long long ret = NSEC_PER_SEC * b.tv_sec + b.tv_nsec;
ret -= NSEC_PER_SEC * a.tv_sec + a.tv_nsec;
return ret;
}
struct timespec timespec_add(struct timespec ts, unsigned long long ns)
{
ts.tv_nsec += ns;
while (ts.tv_nsec >= NSEC_PER_SEC) {
ts.tv_nsec -= NSEC_PER_SEC;
ts.tv_sec++;
}
return ts;
}
int mqueue_lat_test(void)
{
mqd_t q;
struct mq_attr attr;
struct timespec start, end, now, target;
int i, count, ret;
q = mq_open("/foo", O_CREAT | O_RDONLY, 0666, NULL);
if (q < 0) {
perror("mq_open");
return -1;
}
mq_getattr(q, &attr);
count = 100;
clock_gettime(CLOCK_MONOTONIC, &start);
for (i = 0; i < count; i++) {
char buf[attr.mq_msgsize];
clock_gettime(CLOCK_REALTIME, &now);
target = now;
target = timespec_add(now, TARGET_TIMEOUT); /* 100ms */
ret = mq_timedreceive(q, buf, sizeof(buf), NULL, &target);
if (ret < 0 && errno != ETIMEDOUT) {
perror("mq_timedreceive");
return -1;
}
}
clock_gettime(CLOCK_MONOTONIC, &end);
mq_close(q);
if ((timespec_sub(start, end)/count) > TARGET_TIMEOUT + UNRESONABLE_LATENCY)
return -1;
return 0;
}
int main(int argc, char **argv)
{
int ret;
printf("Mqueue latency : ");
ret = mqueue_lat_test();
if (ret < 0) {
printf("[FAILED]\n");
return ksft_exit_fail();
}
printf("[OK]\n");
return ksft_exit_pass();
}