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#include <errno.h> | |
#include <stdlib.h> | |
#include <unistd.h> | |
#include <stdio.h> | |
#include <signal.h> | |
#include <time.h> | |
#include <pthread.h> | |
#include <fcntl.h> | |
#include <string.h> | |
#define CLOCKID CLOCK_PROCESS_CPUTIME_ID | |
#define SIG SIGRTMIN | |
#define errExit(msg) do { perror(msg); exit(EXIT_FAILURE); } while (0) | |
/* This function is intended to rack up both user and system time. */ | |
static void * chew_cpu (void *arg) { | |
while (1) { | |
static volatile char buf[4096]; | |
for (int i = 0; i < 100; ++i) { | |
for (size_t j = 0; j < sizeof buf; ++j) { | |
buf[j] = 0xaa; | |
} | |
} | |
int nullfd = open("/dev/null", O_WRONLY); | |
for(int i = 0; i < 100; ++i) { | |
for (size_t j = 0; j < sizeof buf; ++j) { | |
buf[j] = 0xbb; | |
} | |
} | |
write(nullfd, (char *) buf, sizeof buf); | |
close(nullfd); | |
} | |
return NULL; | |
} | |
int count = 0; | |
int failures = 0; | |
long long freq_nanosecs; | |
pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER; | |
pthread_cond_t cond = PTHREAD_COND_INITIALIZER; | |
void sig_handler(int sig, siginfo_t *si, void *ctx) { | |
pthread_mutex_lock(&lock); | |
++count; | |
pthread_cond_signal(&cond); | |
pthread_mutex_unlock(&lock); | |
} | |
void maketimer() { | |
timer_t timerid; | |
sigset_t mask; | |
struct sigevent sev; | |
struct itimerspec its; | |
struct sigaction sa; | |
sa.sa_flags = SA_SIGINFO; | |
sa.sa_sigaction = sig_handler; | |
sigemptyset(&sa.sa_mask); | |
if (sigaction(SIG, &sa, NULL) == -1) | |
errExit("sigaction"); | |
sev.sigev_notify = SIGEV_SIGNAL; | |
sev.sigev_signo = SIG; | |
sev.sigev_value.sival_ptr = &timerid; | |
long int result; | |
while (result = timer_create(CLOCKID, &sev, &timerid) == -1) { | |
failures++; | |
struct timespec ts = { .tv_sec = 0, .tv_nsec = 100000000 }; | |
nanosleep(&ts, NULL); | |
} | |
/* Start the timer */ | |
its.it_value.tv_sec = freq_nanosecs / 1000000000; | |
its.it_value.tv_nsec = freq_nanosecs % 1000000000; | |
its.it_interval.tv_sec = its.it_value.tv_sec; | |
its.it_interval.tv_nsec = its.it_value.tv_nsec; | |
if (timer_settime(timerid, 0, &its, NULL) == -1) | |
errExit("timer_settime"); | |
} | |
int main(int argc, char *argv[]) { | |
long long wait_count; | |
if (argc != 4) { | |
fprintf(stderr, "Usage: %s <sleep-secs> <freq-nanosecs> <wait-count>\n", argv[0]); | |
exit(EXIT_FAILURE); | |
} | |
wait_count = atoll(argv[3]); | |
freq_nanosecs = atoll(argv[2]); | |
/* Spin up a core so we have some work going on */ | |
printf("Busying the processor with some stuff.\n"); | |
for (int i = 0; i < 32; i++) { | |
pthread_t th; | |
int e = pthread_create(&th, NULL, chew_cpu, NULL); | |
if (e != 0) { | |
printf("pthread_create: %s\n", strerror(e)); | |
exit (1); | |
} | |
} | |
for (int i = 0; i < 10; i++) { | |
maketimer(); | |
} | |
time_t start = time(NULL); | |
while (count < wait_count) { | |
if (time(NULL) > (start + atoi(argv[1]))) { | |
printf("Count is %d, failures %d, sleeping for %ds\n", count, failures, atoi(argv[1])); | |
start = time(NULL); | |
} | |
struct timespec ts = { .tv_sec = 1, .tv_nsec = 0 }; | |
nanosleep(&ts, NULL); | |
} | |
printf("All done, count is %d\n", count); | |
exit(EXIT_SUCCESS); | |
} |
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compile with:
gcc -o stresscputest gistfile1.txt -lpthread -std=gnu99 -lrt