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// SPDX-License-Identifier: GPL-2.0
// Carsten Haitzler <carsten.haitzler@arm.com>, 2021
// define this for gettid()
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <pthread.h>
#include <sys/syscall.h>
#ifndef SYS_gettid
// gettid is 178 on arm64
# define SYS_gettid 178
#endif
#define gettid() syscall(SYS_gettid)
struct args {
unsigned int loops;
pthread_t th;
void *ret;
};
static void *thrfn(void *arg)
{
struct args *a = arg;
int i = 0, len = a->loops;
if (getenv("SHOW_TID")) {
unsigned long long tid = gettid();
printf("%llu\n", tid);
}
asm volatile(
"loop:\n"
"add %[i], %[i], #1\n"
"cmp %[i], %[len]\n"
"blt loop\n"
: /* out */
: /* in */ [i] "r" (i), [len] "r" (len)
: /* clobber */
);
return (void *)(long)i;
}
static pthread_t new_thr(void *(*fn) (void *arg), void *arg)
{
pthread_t t;
pthread_attr_t attr;
pthread_attr_init(&attr);
pthread_create(&t, &attr, fn, arg);
return t;
}
int main(int argc, char **argv)
{
unsigned int i, len, thr;
struct args args[256];
if (argc < 3) {
printf("ERR: %s [numthreads] [numloops (millions)]\n", argv[0]);
exit(1);
}
thr = atoi(argv[1]);
if ((thr < 1) || (thr > 256)) {
printf("ERR: threads 1-256\n");
exit(1);
}
len = atoi(argv[2]);
if ((len < 1) || (len > 4000)) {
printf("ERR: max loops 4000 (millions)\n");
exit(1);
}
len *= 1000000;
for (i = 0; i < thr; i++) {
args[i].loops = len;
args[i].th = new_thr(thrfn, &(args[i]));
}
for (i = 0; i < thr; i++)
pthread_join(args[i].th, &(args[i].ret));
return 0;
}
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