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1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (c) 2023 Meta Platforms, Inc. and affiliates.
4 * Copyright (c) 2023 Tejun Heo <tj@kernel.org>
5 * Copyright (c) 2023 David Vernet <dvernet@meta.com>
6 */
7#include <stdio.h>
8#include <signal.h>
9#include <unistd.h>
10#include <libgen.h>
11#include <limits.h>
12#include <inttypes.h>
13#include <fcntl.h>
14#include <time.h>
15#include <bpf/bpf.h>
16#include <scx/common.h>
17#include "scx_flatcg.h"
18#include "scx_flatcg.bpf.skel.h"
19
20#ifndef FILEID_KERNFS
21#define FILEID_KERNFS 0xfe
22#endif
23
24const char help_fmt[] =
25"A flattened cgroup hierarchy sched_ext scheduler.\n"
26"\n"
27"See the top-level comment in .bpf.c for more details.\n"
28"\n"
29"Usage: %s [-s SLICE_US] [-i INTERVAL] [-f] [-v]\n"
30"\n"
31" -s SLICE_US Override slice duration\n"
32" -i INTERVAL Report interval\n"
33" -f Use FIFO scheduling instead of weighted vtime scheduling\n"
34" -v Print libbpf debug messages\n"
35" -h Display this help and exit\n";
36
37static bool verbose;
38static volatile int exit_req;
39
40static int libbpf_print_fn(enum libbpf_print_level level, const char *format, va_list args)
41{
42 if (level == LIBBPF_DEBUG && !verbose)
43 return 0;
44 return vfprintf(stderr, format, args);
45}
46
47static void sigint_handler(int dummy)
48{
49 exit_req = 1;
50}
51
52static float read_cpu_util(__u64 *last_sum, __u64 *last_idle)
53{
54 FILE *fp;
55 char buf[4096];
56 char *line, *cur = NULL, *tok;
57 __u64 sum = 0, idle = 0;
58 __u64 delta_sum, delta_idle;
59 int idx;
60
61 fp = fopen("/proc/stat", "r");
62 if (!fp) {
63 perror("fopen(\"/proc/stat\")");
64 return 0.0;
65 }
66
67 if (!fgets(buf, sizeof(buf), fp)) {
68 perror("fgets(\"/proc/stat\")");
69 fclose(fp);
70 return 0.0;
71 }
72 fclose(fp);
73
74 line = buf;
75 for (idx = 0; (tok = strtok_r(line, " \n", &cur)); idx++) {
76 char *endp = NULL;
77 __u64 v;
78
79 if (idx == 0) {
80 line = NULL;
81 continue;
82 }
83 v = strtoull(tok, &endp, 0);
84 if (!endp || *endp != '\0') {
85 fprintf(stderr, "failed to parse %dth field of /proc/stat (\"%s\")\n",
86 idx, tok);
87 continue;
88 }
89 sum += v;
90 if (idx == 4)
91 idle = v;
92 }
93
94 delta_sum = sum - *last_sum;
95 delta_idle = idle - *last_idle;
96 *last_sum = sum;
97 *last_idle = idle;
98
99 return delta_sum ? (float)(delta_sum - delta_idle) / delta_sum : 0.0;
100}
101
102static void fcg_read_stats(struct scx_flatcg *skel, __u64 *stats)
103{
104 __u64 cnts[FCG_NR_STATS][skel->rodata->nr_cpus];
105 __u32 idx;
106
107 memset(stats, 0, sizeof(stats[0]) * FCG_NR_STATS);
108
109 for (idx = 0; idx < FCG_NR_STATS; idx++) {
110 int ret, cpu;
111
112 ret = bpf_map_lookup_elem(bpf_map__fd(skel->maps.stats),
113 &idx, cnts[idx]);
114 if (ret < 0)
115 continue;
116 for (cpu = 0; cpu < skel->rodata->nr_cpus; cpu++)
117 stats[idx] += cnts[idx][cpu];
118 }
119}
120
121int main(int argc, char **argv)
122{
123 struct scx_flatcg *skel;
124 struct bpf_link *link;
125 struct timespec intv_ts = { .tv_sec = 2, .tv_nsec = 0 };
126 bool dump_cgrps = false;
127 __u64 last_cpu_sum = 0, last_cpu_idle = 0;
128 __u64 last_stats[FCG_NR_STATS] = {};
129 unsigned long seq = 0;
130 __s32 opt;
131 __u64 ecode;
132
133 libbpf_set_print(libbpf_print_fn);
134 signal(SIGINT, sigint_handler);
135 signal(SIGTERM, sigint_handler);
136restart:
137 skel = SCX_OPS_OPEN(flatcg_ops, scx_flatcg);
138
139 skel->rodata->nr_cpus = libbpf_num_possible_cpus();
140
141 while ((opt = getopt(argc, argv, "s:i:dfvh")) != -1) {
142 double v;
143
144 switch (opt) {
145 case 's':
146 v = strtod(optarg, NULL);
147 skel->rodata->cgrp_slice_ns = v * 1000;
148 break;
149 case 'i':
150 v = strtod(optarg, NULL);
151 intv_ts.tv_sec = v;
152 intv_ts.tv_nsec = (v - (float)intv_ts.tv_sec) * 1000000000;
153 break;
154 case 'd':
155 dump_cgrps = true;
156 break;
157 case 'f':
158 skel->rodata->fifo_sched = true;
159 break;
160 case 'v':
161 verbose = true;
162 break;
163 case 'h':
164 default:
165 fprintf(stderr, help_fmt, basename(argv[0]));
166 return opt != 'h';
167 }
168 }
169
170 printf("slice=%.1lfms intv=%.1lfs dump_cgrps=%d",
171 (double)skel->rodata->cgrp_slice_ns / 1000000.0,
172 (double)intv_ts.tv_sec + (double)intv_ts.tv_nsec / 1000000000.0,
173 dump_cgrps);
174
175 SCX_OPS_LOAD(skel, flatcg_ops, scx_flatcg, uei);
176 link = SCX_OPS_ATTACH(skel, flatcg_ops, scx_flatcg);
177
178 while (!exit_req && !UEI_EXITED(skel, uei)) {
179 __u64 acc_stats[FCG_NR_STATS];
180 __u64 stats[FCG_NR_STATS];
181 float cpu_util;
182 int i;
183
184 cpu_util = read_cpu_util(&last_cpu_sum, &last_cpu_idle);
185
186 fcg_read_stats(skel, acc_stats);
187 for (i = 0; i < FCG_NR_STATS; i++)
188 stats[i] = acc_stats[i] - last_stats[i];
189
190 memcpy(last_stats, acc_stats, sizeof(acc_stats));
191
192 printf("\n[SEQ %6lu cpu=%5.1lf hweight_gen=%" PRIu64 "]\n",
193 seq++, cpu_util * 100.0, skel->data->hweight_gen);
194 printf(" act:%6llu deact:%6llu global:%6llu local:%6llu\n",
195 stats[FCG_STAT_ACT],
196 stats[FCG_STAT_DEACT],
197 stats[FCG_STAT_GLOBAL],
198 stats[FCG_STAT_LOCAL]);
199 printf("HWT cache:%6llu update:%6llu skip:%6llu race:%6llu\n",
200 stats[FCG_STAT_HWT_CACHE],
201 stats[FCG_STAT_HWT_UPDATES],
202 stats[FCG_STAT_HWT_SKIP],
203 stats[FCG_STAT_HWT_RACE]);
204 printf("ENQ skip:%6llu race:%6llu\n",
205 stats[FCG_STAT_ENQ_SKIP],
206 stats[FCG_STAT_ENQ_RACE]);
207 printf("CNS keep:%6llu expire:%6llu empty:%6llu gone:%6llu\n",
208 stats[FCG_STAT_CNS_KEEP],
209 stats[FCG_STAT_CNS_EXPIRE],
210 stats[FCG_STAT_CNS_EMPTY],
211 stats[FCG_STAT_CNS_GONE]);
212 printf("PNC next:%6llu empty:%6llu nocgrp:%6llu gone:%6llu race:%6llu fail:%6llu\n",
213 stats[FCG_STAT_PNC_NEXT],
214 stats[FCG_STAT_PNC_EMPTY],
215 stats[FCG_STAT_PNC_NO_CGRP],
216 stats[FCG_STAT_PNC_GONE],
217 stats[FCG_STAT_PNC_RACE],
218 stats[FCG_STAT_PNC_FAIL]);
219 printf("BAD remove:%6llu\n",
220 acc_stats[FCG_STAT_BAD_REMOVAL]);
221 fflush(stdout);
222
223 nanosleep(&intv_ts, NULL);
224 }
225
226 bpf_link__destroy(link);
227 ecode = UEI_REPORT(skel, uei);
228 scx_flatcg__destroy(skel);
229
230 if (UEI_ECODE_RESTART(ecode))
231 goto restart;
232 return 0;
233}