ebb_vs_cpu_event_test.c

 1// SPDX-License-Identifier: GPL-2.0-only
 2/*
 3 * Copyright 2014, Michael Ellerman, IBM Corp.
 4 */
 5
 6#include <signal.h>
 7#include <stdio.h>
 8#include <stdlib.h>
 9#include <stdbool.h>
10#include <sys/types.h>
11#include <sys/wait.h>
12#include <unistd.h>
13
14#include "ebb.h"
15
16
17/*
18 * Tests an EBB vs a cpu event - in that order. The EBB should force the cpu
19 * event off the PMU.
20 */
21
22static int setup_cpu_event(struct event *event, int cpu)
23{
24	event_init_named(event, 0x400FA, "PM_RUN_INST_CMPL");
25
26	event->attr.exclude_kernel = 1;
27	event->attr.exclude_hv = 1;
28	event->attr.exclude_idle = 1;
29
30	SKIP_IF(require_paranoia_below(1));
31	FAIL_IF(event_open_with_cpu(event, cpu));
32	FAIL_IF(event_enable(event));
33
34	return 0;
35}
36
37int ebb_vs_cpu_event(void)
38{
39	union pipe read_pipe, write_pipe;
40	struct event event;
41	int cpu, rc;
42	pid_t pid;
43
44	SKIP_IF(!ebb_is_supported());
45
46	cpu = bind_to_cpu(BIND_CPU_ANY);
47	FAIL_IF(cpu < 0);
48
49	FAIL_IF(pipe(read_pipe.fds) == -1);
50	FAIL_IF(pipe(write_pipe.fds) == -1);
51
52	pid = fork();
53	if (pid == 0) {
54		/* NB order of pipes looks reversed */
55		exit(ebb_child(write_pipe, read_pipe));
56	}
57
58	/* Signal the child to install its EBB event and wait */
59	FAIL_IF(sync_with_child(read_pipe, write_pipe));
60
61	/* Now try to install our CPU event */
62	rc = setup_cpu_event(&event, cpu);
63	if (rc) {
64		kill_child_and_wait(pid);
65		return rc;
66	}
67
68	/* Signal the child to run */
69	FAIL_IF(sync_with_child(read_pipe, write_pipe));
70
71	/* .. and wait for it to complete */
72	FAIL_IF(wait_for_child(pid));
73	FAIL_IF(event_disable(&event));
74	FAIL_IF(event_read(&event));
75
76	event_report(&event);
77
78	/* The cpu event may have run, but we don't expect 100% */
79	FAIL_IF(event.result.enabled >= event.result.running);
80
81	return 0;
82}
83
84int main(void)
85{
86	return test_harness(ebb_vs_cpu_event, "ebb_vs_cpu_event");
87}