114 lines
2.8 KiB
C
114 lines
2.8 KiB
C
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/*
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* Copyright 2015, Cyril Bur, IBM Corp.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* This test attempts to see if the FPU registers change across preemption.
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* Two things should be noted here a) The check_fpu function in asm only checks
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* the non volatile registers as it is reused from the syscall test b) There is
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* no way to be sure preemption happened so this test just uses many threads
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* and a long wait. As such, a successful test doesn't mean much but a failure
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* is bad.
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*/
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#include <stdio.h>
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#include <unistd.h>
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#include <sys/syscall.h>
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#include <sys/time.h>
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#include <sys/types.h>
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#include <sys/wait.h>
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#include <stdlib.h>
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#include <pthread.h>
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#include "utils.h"
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/* Time to wait for workers to get preempted (seconds) */
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#define PREEMPT_TIME 20
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/*
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* Factor by which to multiply number of online CPUs for total number of
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* worker threads
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*/
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#define THREAD_FACTOR 8
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__thread double darray[] = {0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0,
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1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0,
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2.1};
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int threads_starting;
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int running;
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extern void preempt_fpu(double *darray, int *threads_starting, int *running);
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void *preempt_fpu_c(void *p)
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{
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int i;
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srand(pthread_self());
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for (i = 0; i < 21; i++)
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darray[i] = rand();
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/* Test failed if it ever returns */
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preempt_fpu(darray, &threads_starting, &running);
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return p;
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}
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int test_preempt_fpu(void)
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{
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int i, rc, threads;
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pthread_t *tids;
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threads = sysconf(_SC_NPROCESSORS_ONLN) * THREAD_FACTOR;
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tids = malloc((threads) * sizeof(pthread_t));
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FAIL_IF(!tids);
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running = true;
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threads_starting = threads;
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for (i = 0; i < threads; i++) {
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rc = pthread_create(&tids[i], NULL, preempt_fpu_c, NULL);
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FAIL_IF(rc);
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}
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setbuf(stdout, NULL);
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/* Not really necessary but nice to wait for every thread to start */
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printf("\tWaiting for all workers to start...");
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while(threads_starting)
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asm volatile("": : :"memory");
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printf("done\n");
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printf("\tWaiting for %d seconds to let some workers get preempted...", PREEMPT_TIME);
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sleep(PREEMPT_TIME);
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printf("done\n");
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printf("\tStopping workers...");
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/*
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* Working are checking this value every loop. In preempt_fpu 'cmpwi r5,0; bne 2b'.
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* r5 will have loaded the value of running.
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*/
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running = 0;
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for (i = 0; i < threads; i++) {
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void *rc_p;
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pthread_join(tids[i], &rc_p);
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/*
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* Harness will say the fail was here, look at why preempt_fpu
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* returned
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*/
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if ((long) rc_p)
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printf("oops\n");
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FAIL_IF((long) rc_p);
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}
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printf("done\n");
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free(tids);
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return 0;
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}
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int main(int argc, char *argv[])
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{
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return test_harness(test_preempt_fpu, "fpu_preempt");
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}
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