2 * Copyright 2015, Cyril Bur, IBM Corp.
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License
6 * as published by the Free Software Foundation; either version
7 * 2 of the License, or (at your option) any later version.
9 * This test attempts to see if the FPU registers change across preemption.
10 * Two things should be noted here a) The check_fpu function in asm only checks
11 * the non volatile registers as it is reused from the syscall test b) There is
12 * no way to be sure preemption happened so this test just uses many threads
13 * and a long wait. As such, a successful test doesn't mean much but a failure
19 #include <sys/syscall.h>
21 #include <sys/types.h>
28 /* Time to wait for workers to get preempted (seconds) */
29 #define PREEMPT_TIME 20
31 * Factor by which to multiply number of online CPUs for total number of
34 #define THREAD_FACTOR 8
37 __thread double darray[] = {0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,
38 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0,
44 extern void preempt_fpu(double *darray, int *threads_starting, int *running);
46 void *preempt_fpu_c(void *p)
49 srand(pthread_self());
50 for (i = 0; i < 21; i++)
53 /* Test failed if it ever returns */
54 preempt_fpu(darray, &threads_starting, &running);
59 int test_preempt_fpu(void)
64 threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
65 tids = malloc((threads) * sizeof(pthread_t));
69 threads_starting = threads;
70 for (i = 0; i < threads; i++) {
71 rc = pthread_create(&tids[i], NULL, preempt_fpu_c, NULL);
76 /* Not really necessary but nice to wait for every thread to start */
77 printf("\tWaiting for all workers to start...");
78 while(threads_starting)
79 asm volatile("": : :"memory");
82 printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
86 printf("\tStopping workers...");
88 * Working are checking this value every loop. In preempt_fpu 'cmpwi r5,0; bne 2b'.
89 * r5 will have loaded the value of running.
92 for (i = 0; i < threads; i++) {
94 pthread_join(tids[i], &rc_p);
97 * Harness will say the fail was here, look at why preempt_fpu
102 FAIL_IF((long) rc_p);
110 int main(int argc, char *argv[])
112 return test_harness(test_preempt_fpu, "fpu_preempt");