1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright 2014, Michael Ellerman, IBM Corp.
4  */
5 
6 #include <stdbool.h>
7 #include <stdio.h>
8 #include <stdlib.h>
9 #include <signal.h>
10 
11 #include "ebb.h"
12 
13 
14 /*
15  * Test running multiple EBB using processes at once on a single CPU. They
16  * should all run happily without interfering with each other.
17  */
18 
19 static bool child_should_exit;
20 
21 static void sigint_handler(int signal)
22 {
23 	child_should_exit = true;
24 }
25 
26 struct sigaction sigint_action = {
27 	.sa_handler = sigint_handler,
28 };
29 
30 static int cycles_child(void)
31 {
32 	struct event event;
33 
34 	if (sigaction(SIGINT, &sigint_action, NULL)) {
35 		perror("sigaction");
36 		return 1;
37 	}
38 
39 	event_init_named(&event, 0x1001e, "cycles");
40 	event_leader_ebb_init(&event);
41 
42 	event.attr.exclude_kernel = 1;
43 	event.attr.exclude_hv = 1;
44 	event.attr.exclude_idle = 1;
45 
46 	FAIL_IF(event_open(&event));
47 
48 	ebb_enable_pmc_counting(1);
49 	setup_ebb_handler(standard_ebb_callee);
50 	ebb_global_enable();
51 
52 	FAIL_IF(ebb_event_enable(&event));
53 
54 	mtspr(SPRN_PMC1, pmc_sample_period(sample_period));
55 
56 	while (!child_should_exit) {
57 		FAIL_IF(core_busy_loop());
58 		FAIL_IF(ebb_check_mmcr0());
59 	}
60 
61 	ebb_global_disable();
62 	ebb_freeze_pmcs();
63 
64 	dump_summary_ebb_state();
65 
66 	event_close(&event);
67 
68 	FAIL_IF(ebb_state.stats.ebb_count == 0);
69 
70 	return 0;
71 }
72 
73 #define NR_CHILDREN	4
74 
75 int multi_ebb_procs(void)
76 {
77 	pid_t pids[NR_CHILDREN];
78 	int cpu, rc, i;
79 
80 	SKIP_IF(!ebb_is_supported());
81 
82 	cpu = pick_online_cpu();
83 	FAIL_IF(cpu < 0);
84 	FAIL_IF(bind_to_cpu(cpu));
85 
86 	for (i = 0; i < NR_CHILDREN; i++) {
87 		pids[i] = fork();
88 		if (pids[i] == 0)
89 			exit(cycles_child());
90 	}
91 
92 	/* Have them all run for "a while" */
93 	sleep(10);
94 
95 	rc = 0;
96 	for (i = 0; i < NR_CHILDREN; i++) {
97 		/* Tell them to stop */
98 		kill(pids[i], SIGINT);
99 		/* And wait */
100 		rc |= wait_for_child(pids[i]);
101 	}
102 
103 	return rc;
104 }
105 
106 int main(void)
107 {
108 	return test_harness(multi_ebb_procs, "multi_ebb_procs");
109 }
110