// SPDX-License-Identifier: GPL-2.0
// Carsten Haitzler <[email protected]>, 2021
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <pthread.h>
struct args {
pthread_t th;
unsigned int in;
void *ret;
};
static void *thrfn(void *arg)
{
struct args *a = arg;
unsigned int i, in = a->in;
for (i = 0; i < 10000; i++) {
asm volatile (
// force an unroll of thia add instruction so we can test long runs of code
#define SNIP1 "add %[in], %[in], #1\n"
// 10
#define SNIP2 SNIP1 SNIP1 SNIP1 SNIP1 SNIP1 SNIP1 SNIP1 SNIP1 SNIP1 SNIP1
// 100
#define SNIP3 SNIP2 SNIP2 SNIP2 SNIP2 SNIP2 SNIP2 SNIP2 SNIP2 SNIP2 SNIP2
// 1000
#define SNIP4 SNIP3 SNIP3 SNIP3 SNIP3 SNIP3 SNIP3 SNIP3 SNIP3 SNIP3 SNIP3
// 10000
#define SNIP5 SNIP4 SNIP4 SNIP4 SNIP4 SNIP4 SNIP4 SNIP4 SNIP4 SNIP4 SNIP4
// 100000
SNIP5 SNIP5 SNIP5 SNIP5 SNIP5 SNIP5 SNIP5 SNIP5 SNIP5 SNIP5
: /* out */
: /* in */ [in] "r" (in)
: /* clobber */
);
}
}
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, thr;
struct args args[256];
if (argc < 2) {
printf("ERR: %s [numthreads]\n", argv[0]);
exit(1);
}
thr = atoi(argv[1]);
if ((thr > 256) || (thr < 1)) {
printf("ERR: threads 1-256\n");
exit(1);
}
for (i = 0; i < thr; i++) {
args[i].in = rand();
args[i].th = new_thr(thrfn, &(args[i]));
}
for (i = 0; i < thr; i++)
pthread_join(args[i].th, &(args[i].ret));
return 0;
}