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linux/tools/testing/selftests/powerpc/math/fpu_preempt.c
Michael Ellerman 60d2c3af9a selftests/powerpc: Run fpu_preempt test for 60 seconds
The FPU preempt test only runs for 20 seconds, which is not particularly
long. Run it for 60 seconds to increase the chance of detecting
corruption.

Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20231128132748.1990179-4-mpe@ellerman.id.au
2023-12-13 13:29:09 +11:00

105 lines
2.4 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright 2015, Cyril Bur, IBM Corp.
* Copyright 2023, Michael Ellerman, IBM Corp.
*
* This test attempts to see if the FPU 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 <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"
#include "fpu.h"
/* Time to wait for workers to get preempted (seconds) */
#define PREEMPT_TIME 60
/*
* Factor by which to multiply number of online CPUs for total number of
* worker threads
*/
#define THREAD_FACTOR 8
__thread double darray[32];
int threads_starting;
int running;
extern int preempt_fpu(double *darray, int *threads_starting, int *running);
void *preempt_fpu_c(void *p)
{
long rc;
srand(pthread_self());
randomise_darray(darray, ARRAY_SIZE(darray));
rc = preempt_fpu(darray, &threads_starting, &running);
return (void *)rc;
}
int test_preempt_fpu(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_fpu_c, NULL);
FAIL_IF(rc);
}
setbuf(stdout, NULL);
/* Not really necessary but nice to wait for every thread to start */
printf("\tWaiting for all workers to start...");
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_fpu '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_fpu
* returned
*/
if ((long) rc_p)
printf("oops\n");
FAIL_IF((long) rc_p);
}
printf("done\n");
free(tids);
return 0;
}
int main(int argc, char *argv[])
{
return test_harness(test_preempt_fpu, "fpu_preempt");
}