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 <assert.h>
11 #include <libgen.h>
12 #include <bpf/bpf.h>
13 #include <scx/common.h>
14 #include "scx_simple.bpf.skel.h"
15
16 const char help_fmt[] =
17 "A simple sched_ext scheduler.\n"
18 "\n"
19 "See the top-level comment in .bpf.c for more details.\n"
20 "\n"
21 "Usage: %s [-f] [-v]\n"
22 "\n"
23 " -f Use FIFO scheduling instead of weighted vtime scheduling\n"
24 " -v Print libbpf debug messages\n"
25 " -h Display this help and exit\n";
26
27 static bool verbose;
28 static volatile int exit_req;
29
libbpf_print_fn(enum libbpf_print_level level,const char * format,va_list args)30 static int libbpf_print_fn(enum libbpf_print_level level, const char *format, va_list args)
31 {
32 if (level == LIBBPF_DEBUG && !verbose)
33 return 0;
34 return vfprintf(stderr, format, args);
35 }
36
sigint_handler(int simple)37 static void sigint_handler(int simple)
38 {
39 exit_req = 1;
40 }
41
read_stats(struct scx_simple * skel,__u64 * stats)42 static void read_stats(struct scx_simple *skel, __u64 *stats)
43 {
44 int nr_cpus = libbpf_num_possible_cpus();
45 assert(nr_cpus > 0);
46 __u64 cnts[2][nr_cpus];
47 __u32 idx;
48
49 memset(stats, 0, sizeof(stats[0]) * 2);
50
51 for (idx = 0; idx < 2; idx++) {
52 int ret, cpu;
53
54 ret = bpf_map_lookup_elem(bpf_map__fd(skel->maps.stats),
55 &idx, cnts[idx]);
56 if (ret < 0)
57 continue;
58 for (cpu = 0; cpu < nr_cpus; cpu++)
59 stats[idx] += cnts[idx][cpu];
60 }
61 }
62
main(int argc,char ** argv)63 int main(int argc, char **argv)
64 {
65 struct scx_simple *skel;
66 struct bpf_link *link;
67 __u32 opt;
68 __u64 ecode;
69
70 libbpf_set_print(libbpf_print_fn);
71 signal(SIGINT, sigint_handler);
72 signal(SIGTERM, sigint_handler);
73 restart:
74 skel = SCX_OPS_OPEN(simple_ops, scx_simple);
75
76 while ((opt = getopt(argc, argv, "fvh")) != -1) {
77 switch (opt) {
78 case 'f':
79 skel->rodata->fifo_sched = true;
80 break;
81 case 'v':
82 verbose = true;
83 break;
84 default:
85 fprintf(stderr, help_fmt, basename(argv[0]));
86 return opt != 'h';
87 }
88 }
89
90 SCX_OPS_LOAD(skel, simple_ops, scx_simple, uei);
91 link = SCX_OPS_ATTACH(skel, simple_ops, scx_simple);
92
93 while (!exit_req && !UEI_EXITED(skel, uei)) {
94 __u64 stats[2];
95
96 read_stats(skel, stats);
97 printf("local=%llu global=%llu\n", stats[0], stats[1]);
98 fflush(stdout);
99 sleep(1);
100 }
101
102 bpf_link__destroy(link);
103 ecode = UEI_REPORT(skel, uei);
104 scx_simple__destroy(skel);
105
106 if (UEI_ECODE_RESTART(ecode))
107 goto restart;
108 return 0;
109 }
110