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/*
* Copyright 2020 Matt Fleming
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
static inline unsigned long
clock_delta_now_secs(struct timespec *s)
{
struct timespec now;
clock_gettime(CLOCK_MONOTONIC_RAW, &now);
return now.tv_sec - s->tv_sec;
}
static inline unsigned long
clock_delta_now_ns(struct timespec *s)
{
struct timespec now;
clock_gettime(CLOCK_MONOTONIC_RAW, &now);
return now.tv_nsec - s->tv_nsec;
}
static inline void spin(unsigned long ns)
{
struct timespec s;
clock_gettime(CLOCK_MONOTONIC_RAW, &s);
while (clock_delta_now_ns(&s) < ns)
;
}
int main(int argc, char **argv)
{
unsigned long duration, count;
struct timespec start;
if (argc < 2) {
fprintf(stderr, "Usage: random-syscall <duration (secs)>\n");
exit(1);
}
duration = strtoul(argv[1], NULL, 10);
printf("Executing for %lu secs\n", duration);
clock_gettime(CLOCK_MONOTONIC_RAW, &start);
for (count = 0; clock_delta_now_secs(&start) < duration; count++) {
struct timespec ns = {
.tv_sec = 0,
.tv_nsec = 10,
};
if (rand() % 2) {
nanosleep(&ns, NULL);
} else {
spin(3000);
}
}
printf("Loop count: %lu\n", count);
return 0;
}
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