select_cpu_dfl.c

 1/* SPDX-License-Identifier: GPL-2.0 */
 2/*
 3 * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
 4 * Copyright (c) 2023 David Vernet <dvernet@meta.com>
 5 * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
 6 */
 7#include <bpf/bpf.h>
 8#include <scx/common.h>
 9#include <sys/wait.h>
10#include <unistd.h>
11#include "select_cpu_dfl.bpf.skel.h"
12#include "scx_test.h"
13
14#define NUM_CHILDREN 1028
15
16static enum scx_test_status setup(void **ctx)
17{
18	struct select_cpu_dfl *skel;
19
20	skel = select_cpu_dfl__open();
21	SCX_FAIL_IF(!skel, "Failed to open");
22	SCX_ENUM_INIT(skel);
23	SCX_FAIL_IF(select_cpu_dfl__load(skel), "Failed to load skel");
24
25	*ctx = skel;
26
27	return SCX_TEST_PASS;
28}
29
30static enum scx_test_status run(void *ctx)
31{
32	struct select_cpu_dfl *skel = ctx;
33	struct bpf_link *link;
34	pid_t pids[NUM_CHILDREN];
35	int i, status;
36
37	link = bpf_map__attach_struct_ops(skel->maps.select_cpu_dfl_ops);
38	SCX_FAIL_IF(!link, "Failed to attach scheduler");
39
40	for (i = 0; i < NUM_CHILDREN; i++) {
41		pids[i] = fork();
42		if (pids[i] == 0) {
43			sleep(1);
44			exit(0);
45		}
46	}
47
48	for (i = 0; i < NUM_CHILDREN; i++) {
49		SCX_EQ(waitpid(pids[i], &status, 0), pids[i]);
50		SCX_EQ(status, 0);
51	}
52
53	SCX_ASSERT(!skel->bss->saw_local);
54
55	bpf_link__destroy(link);
56
57	return SCX_TEST_PASS;
58}
59
60static void cleanup(void *ctx)
61{
62	struct select_cpu_dfl *skel = ctx;
63
64	select_cpu_dfl__destroy(skel);
65}
66
67struct scx_test select_cpu_dfl = {
68	.name = "select_cpu_dfl",
69	.description = "Verify the default ops.select_cpu() dispatches tasks "
70		       "when idles cores are found, and skips ops.enqueue()",
71	.setup = setup,
72	.run = run,
73	.cleanup = cleanup,
74};
75REGISTER_SCX_TEST(&select_cpu_dfl)