1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (c) 2022 Meta Platforms, Inc. and affiliates.
4 * Copyright (c) 2022 Tejun Heo <tj@kernel.org>
5 * Copyright (c) 2022 David Vernet <dvernet@meta.com>
6 */
7#include <stdio.h>
8#include <unistd.h>
9#include <signal.h>
10#include <libgen.h>
11#include <bpf/bpf.h>
12#include <scx/common.h>
13#include "scx_simple.bpf.skel.h"
14
15const char help_fmt[] =
16"A simple sched_ext scheduler.\n"
17"\n"
18"See the top-level comment in .bpf.c for more details.\n"
19"\n"
20"Usage: %s [-f] [-v]\n"
21"\n"
22" -f Use FIFO scheduling instead of weighted vtime scheduling\n"
23" -v Print libbpf debug messages\n"
24" -h Display this help and exit\n";
25
26static bool verbose;
27static volatile int exit_req;
28
29static int libbpf_print_fn(enum libbpf_print_level level, const char *format, va_list args)
30{
31 if (level == LIBBPF_DEBUG && !verbose)
32 return 0;
33 return vfprintf(stderr, format: format, arg: args);
34}
35
36static void sigint_handler(int simple)
37{
38 exit_req = 1;
39}
40
41static void read_stats(struct scx_simple *skel, __u64 *stats)
42{
43 int nr_cpus = libbpf_num_possible_cpus();
44 __u64 cnts[2][nr_cpus];
45 __u32 idx;
46
47 memset(stats, 0, sizeof(stats[0]) * 2);
48
49 for (idx = 0; idx < 2; idx++) {
50 int ret, cpu;
51
52 ret = bpf_map_lookup_elem(bpf_map__fd(skel->maps.stats),
53 &idx, cnts[idx]);
54 if (ret < 0)
55 continue;
56 for (cpu = 0; cpu < nr_cpus; cpu++)
57 stats[idx] += cnts[idx][cpu];
58 }
59}
60
61int main(int argc, char **argv)
62{
63 struct scx_simple *skel;
64 struct bpf_link *link;
65 __u32 opt;
66 __u64 ecode;
67
68 libbpf_set_print(libbpf_print_fn);
69 signal(SIGINT, handler: sigint_handler);
70 signal(SIGTERM, handler: sigint_handler);
71restart:
72 skel = SCX_OPS_OPEN(simple_ops, scx_simple);
73
74 while ((opt = getopt(argc, argv, "fvh")) != -1) {
75 switch (opt) {
76 case 'f':
77 skel->rodata->fifo_sched = true;
78 break;
79 case 'v':
80 verbose = true;
81 break;
82 default:
83 fprintf(stderr, format: help_fmt, basename(path: argv[0]));
84 return opt != 'h';
85 }
86 }
87
88 SCX_OPS_LOAD(skel, simple_ops, scx_simple, uei);
89 link = SCX_OPS_ATTACH(skel, simple_ops, scx_simple);
90
91 while (!exit_req && !UEI_EXITED(skel, uei)) {
92 __u64 stats[2];
93
94 read_stats(skel, stats);
95 printf("local=%llu global=%llu\n", stats[0], stats[1]);
96 fflush(stdout);
97 sleep(seconds: 1);
98 }
99
100 bpf_link__destroy(link);
101 ecode = UEI_REPORT(skel, uei);
102 scx_simple__destroy(skel);
103
104 if (UEI_ECODE_RESTART(ecode))
105 goto restart;
106 return 0;
107}
108

source code of linux/tools/sched_ext/scx_simple.c