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/*
* Copyright 2015, Cyril Bur, IBM Corp.
*
* 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 test attempts to see if the VSX registers change across preemption.
* There is no way to be sure preemption happened so this test just
* uses many threads and a long wait. As such, a successful test
* doesn't mean much but a failure is bad.
*/
#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <pthread.h>
#include "utils.h"
/* Time to wait for workers to get preempted (seconds) */
#define PREEMPT_TIME 20
/*
* Factor by which to multiply number of online CPUs for total number of
* worker threads
*/
#define THREAD_FACTOR 8
/*
* Ensure there is twice the number of non-volatile VMX regs!
* check_vmx() is going to use the other half as space to put the live
* registers before calling vsx_memcmp()
*/
__thread vector int varray[24] = {
{1, 2, 3, 4 }, {5, 6, 7, 8 }, {9, 10,11,12},
{13,14,15,16}, {17,18,19,20}, {21,22,23,24},
{25,26,27,28}, {29,30,31,32}, {33,34,35,36},
{37,38,39,40}, {41,42,43,44}, {45,46,47,48}
};
int threads_starting;
int running;
extern long preempt_vsx(vector int *varray, int *threads_starting, int *running);
long vsx_memcmp(vector int *a) {
vector int zero = {0, 0, 0, 0};
int i;
FAIL_IF(a != varray);
for(i = 0; i < 12; i++) {
if (memcmp(&a[i + 12], &zero, sizeof(vector int)) == 0) {
fprintf(stderr, "Detected zero from the VSX reg %d\n", i + 12);
return 2;
}
}
if (memcmp(a, &a[12], 12 * sizeof(vector int))) {
long *p = (long *)a;
fprintf(stderr, "VSX mismatch\n");
for (i = 0; i < 24; i=i+2)
fprintf(stderr, "%d: 0x%08lx%08lx | 0x%08lx%08lx\n",
i/2 + i%2 + 20, p[i], p[i + 1], p[i + 24], p[i + 25]);
return 1;
}
return 0;
}
void *preempt_vsx_c(void *p)
{
int i, j;
long rc;
srand(pthread_self());
for (i = 0; i < 12; i++)
for (j = 0; j < 4; j++) {
varray[i][j] = rand();
/* Don't want zero because it hides kernel problems */
if (varray[i][j] == 0)
j--;
}
rc = preempt_vsx(varray, &threads_starting, &running);
if (rc == 2)
fprintf(stderr, "Caught zeros in VSX compares\n");
return (void *)rc;
}
int test_preempt_vsx(void)
{
int i, rc, threads;
pthread_t *tids;
threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
tids = malloc(threads * sizeof(pthread_t));
FAIL_IF(!tids);
running = true;
threads_starting = threads;
for (i = 0; i < threads; i++) {
rc = pthread_create(&tids[i], NULL, preempt_vsx_c, NULL);
FAIL_IF(rc);
}
setbuf(stdout, NULL);
/* Not really nessesary but nice to wait for every thread to start */
printf("\tWaiting for %d workers to start...", threads_starting);
while(threads_starting)
asm volatile("": : :"memory");
printf("done\n");
printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
sleep(PREEMPT_TIME);
printf("done\n");
printf("\tStopping workers...");
/*
* Working are checking this value every loop. In preempt_vsx 'cmpwi r5,0; bne 2b'.
* r5 will have loaded the value of running.
*/
running = 0;
for (i = 0; i < threads; i++) {
void *rc_p;
pthread_join(tids[i], &rc_p);
/*
* Harness will say the fail was here, look at why preempt_vsx
* returned
*/
if ((long) rc_p)
printf("oops\n");
FAIL_IF((long) rc_p);
}
printf("done\n");
return 0;
}
int main(int argc, char *argv[])
{
return test_harness(test_preempt_vsx, "vsx_preempt");
}
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