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authorCyril Bur <cyrilbur@gmail.com>2016-02-29 17:53:44 +1100
committerMichael Ellerman <mpe@ellerman.id.au>2016-03-02 23:34:47 +1100
commite5ab8be68e4421d7f8d4e69e2a8ddb3d69508d2a (patch)
tree5a938174a6c5062aded2cb0015563b63f9c2f532 /tools/testing/selftests/powerpc/math/vmx_preempt.c
parentselftests/powerpc: Test the preservation of FPU and VMX regs across syscall (diff)
downloadlinux-dev-e5ab8be68e4421d7f8d4e69e2a8ddb3d69508d2a.tar.xz
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selftests/powerpc: Test preservation of FPU and VMX regs across preemption
Loop in assembly checking the registers with many threads. Signed-off-by: Cyril Bur <cyrilbur@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'tools/testing/selftests/powerpc/math/vmx_preempt.c')
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diff --git a/tools/testing/selftests/powerpc/math/vmx_preempt.c b/tools/testing/selftests/powerpc/math/vmx_preempt.c
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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 VMX registers change across preemption.
+ * Two things should be noted here a) The check_vmx function in asm only checks
+ * the non volatile registers as it is reused from the syscall test b) 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"
+
+/* 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
+
+__thread vector int varray[] = {{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 void preempt_vmx(vector int *varray, int *threads_starting, int *running);
+
+void *preempt_vmx_c(void *p)
+{
+ int i, j;
+ srand(pthread_self());
+ for (i = 0; i < 12; i++)
+ for (j = 0; j < 4; j++)
+ varray[i][j] = rand();
+
+ /* Test fails if it ever returns */
+ preempt_vmx(varray, &threads_starting, &running);
+ return p;
+}
+
+int test_preempt_vmx(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_vmx_c, NULL);
+ FAIL_IF(rc);
+ }
+
+ setbuf(stdout, NULL);
+ /* Not really nessesary 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_vmx '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_vmx
+ * 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_vmx, "vmx_preempt");
+}