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, 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, sigint_handler);
 70	signal(SIGTERM, 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, help_fmt, basename(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(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}