1 // SPDX-License-Identifier: GPL-2.0
2
3 #define _GNU_SOURCE
4 #include <errno.h>
5 #include <stdio.h>
6 #include <stdlib.h>
7 #include <signal.h>
8 #include <sched.h>
9 #include <string.h>
10 #include <unistd.h>
11 #include <fcntl.h>
12 #include <locale.h>
13 #include <sys/types.h>
14 #include <sys/stat.h>
15 #include <sys/time.h>
16 #include <sys/wait.h>
17
18 #include <bpf/bpf.h>
19 #include <bpf/libbpf.h>
20
21 static int cstate_map_fd, pstate_map_fd;
22
23 #define MAX_CPU 8
24 #define MAX_PSTATE_ENTRIES 5
25 #define MAX_CSTATE_ENTRIES 3
26 #define MAX_STARS 40
27
28 #define CPUFREQ_MAX_SYSFS_PATH "/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq"
29 #define CPUFREQ_LOWEST_FREQ "208000"
30 #define CPUFREQ_HIGHEST_FREQ "12000000"
31
32 struct cpu_stat_data {
33 unsigned long cstate[MAX_CSTATE_ENTRIES];
34 unsigned long pstate[MAX_PSTATE_ENTRIES];
35 };
36
37 static struct cpu_stat_data stat_data[MAX_CPU];
38
39 static void cpu_stat_print(void)
40 {
41 int i, j;
42 char state_str[sizeof("cstate-9")];
43 struct cpu_stat_data *data;
44
45 /* Clear screen */
46 printf("\033[2J");
47
48 /* Header */
49 printf("\nCPU states statistics:\n");
50 printf("%-10s ", "state(ms)");
51
52 for (i = 0; i < MAX_CSTATE_ENTRIES; i++) {
53 sprintf(state_str, "cstate-%d", i);
54 printf("%-11s ", state_str);
55 }
56
57 for (i = 0; i < MAX_PSTATE_ENTRIES; i++) {
58 sprintf(state_str, "pstate-%d", i);
59 printf("%-11s ", state_str);
60 }
61
62 printf("\n");
63
64 for (j = 0; j < MAX_CPU; j++) {
65 data = &stat_data[j];
66
67 printf("CPU-%-6d ", j);
68 for (i = 0; i < MAX_CSTATE_ENTRIES; i++)
69 printf("%-11lu ", data->cstate[i] / 1000000);
70
71 for (i = 0; i < MAX_PSTATE_ENTRIES; i++)
72 printf("%-11lu ", data->pstate[i] / 1000000);
73
74 printf("\n");
75 }
76 }
77
78 static void cpu_stat_update(int cstate_fd, int pstate_fd)
79 {
80 unsigned long key, value;
81 int c, i;
82
83 for (c = 0; c < MAX_CPU; c++) {
84 for (i = 0; i < MAX_CSTATE_ENTRIES; i++) {
85 key = c * MAX_CSTATE_ENTRIES + i;
86 bpf_map_lookup_elem(cstate_fd, &key, &value);
87 stat_data[c].cstate[i] = value;
88 }
89
90 for (i = 0; i < MAX_PSTATE_ENTRIES; i++) {
91 key = c * MAX_PSTATE_ENTRIES + i;
92 bpf_map_lookup_elem(pstate_fd, &key, &value);
93 stat_data[c].pstate[i] = value;
94 }
95 }
96 }
97
98 /*
99 * This function is copied from 'idlestat' tool function
100 * idlestat_wake_all() in idlestate.c.
101 *
102 * It sets the self running task affinity to cpus one by one so can wake up
103 * the specific CPU to handle scheduling; this results in all cpus can be
104 * waken up once and produce ftrace event 'trace_cpu_idle'.
105 */
106 static int cpu_stat_inject_cpu_idle_event(void)
107 {
108 int rcpu, i, ret;
109 cpu_set_t cpumask;
110 cpu_set_t original_cpumask;
111
112 ret = sysconf(_SC_NPROCESSORS_CONF);
113 if (ret < 0)
114 return -1;
115
116 rcpu = sched_getcpu();
117 if (rcpu < 0)
118 return -1;
119
120 /* Keep track of the CPUs we will run on */
121 sched_getaffinity(0, sizeof(original_cpumask), &original_cpumask);
122
123 for (i = 0; i < ret; i++) {
124
125 /* Pointless to wake up ourself */
126 if (i == rcpu)
127 continue;
128
129 /* Pointless to wake CPUs we will not run on */
130 if (!CPU_ISSET(i, &original_cpumask))
131 continue;
132
133 CPU_ZERO(&cpumask);
134 CPU_SET(i, &cpumask);
135
136 sched_setaffinity(0, sizeof(cpumask), &cpumask);
137 }
138
139 /* Enable all the CPUs of the original mask */
140 sched_setaffinity(0, sizeof(original_cpumask), &original_cpumask);
141 return 0;
142 }
143
144 /*
145 * It's possible to have no any frequency change for long time and cannot
146 * get ftrace event 'trace_cpu_frequency' for long period, this introduces
147 * big deviation for pstate statistics.
148 *
149 * To solve this issue, below code forces to set 'scaling_max_freq' to 208MHz
150 * for triggering ftrace event 'trace_cpu_frequency' and then recovery back to
151 * the maximum frequency value 1.2GHz.
152 */
153 static int cpu_stat_inject_cpu_frequency_event(void)
154 {
155 int len, fd;
156
157 fd = open(CPUFREQ_MAX_SYSFS_PATH, O_WRONLY);
158 if (fd < 0) {
159 printf("failed to open scaling_max_freq, errno=%d\n", errno);
160 return fd;
161 }
162
163 len = write(fd, CPUFREQ_LOWEST_FREQ, strlen(CPUFREQ_LOWEST_FREQ));
164 if (len < 0) {
165 printf("failed to open scaling_max_freq, errno=%d\n", errno);
166 goto err;
167 }
168
169 len = write(fd, CPUFREQ_HIGHEST_FREQ, strlen(CPUFREQ_HIGHEST_FREQ));
170 if (len < 0) {
171 printf("failed to open scaling_max_freq, errno=%d\n", errno);
172 goto err;
173 }
174
175 err:
176 close(fd);
177 return len;
178 }
179
180 static void int_exit(int sig)
181 {
182 cpu_stat_inject_cpu_idle_event();
183 cpu_stat_inject_cpu_frequency_event();
184 cpu_stat_update(cstate_map_fd, pstate_map_fd);
185 cpu_stat_print();
186 exit(0);
187 }
188
189 int main(int argc, char **argv)
190 {
191 struct bpf_link *link = NULL;
192 struct bpf_program *prog;
193 struct bpf_object *obj;
194 char filename[256];
195 int ret;
196
197 snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
198 obj = bpf_object__open_file(filename, NULL);
199 if (libbpf_get_error(obj)) {
200 fprintf(stderr, "ERROR: opening BPF object file failed\n");
201 return 0;
202 }
203
204 prog = bpf_object__find_program_by_name(obj, "bpf_prog1");
205 if (!prog) {
206 printf("finding a prog in obj file failed\n");
207 goto cleanup;
208 }
209
210 /* load BPF program */
211 if (bpf_object__load(obj)) {
212 fprintf(stderr, "ERROR: loading BPF object file failed\n");
213 goto cleanup;
214 }
215
216 cstate_map_fd = bpf_object__find_map_fd_by_name(obj, "cstate_duration");
217 pstate_map_fd = bpf_object__find_map_fd_by_name(obj, "pstate_duration");
218 if (cstate_map_fd < 0 || pstate_map_fd < 0) {
219 fprintf(stderr, "ERROR: finding a map in obj file failed\n");
220 goto cleanup;
221 }
222
223 link = bpf_program__attach(prog);
224 if (libbpf_get_error(link)) {
225 fprintf(stderr, "ERROR: bpf_program__attach failed\n");
226 link = NULL;
227 goto cleanup;
228 }
229
230 ret = cpu_stat_inject_cpu_idle_event();
231 if (ret < 0)
232 return 1;
233
234 ret = cpu_stat_inject_cpu_frequency_event();
235 if (ret < 0)
236 return 1;
237
238 signal(SIGINT, int_exit);
239 signal(SIGTERM, int_exit);
240
241 while (1) {
242 cpu_stat_update(cstate_map_fd, pstate_map_fd);
243 cpu_stat_print();
244 sleep(5);
245 }
246
247 cleanup:
248 bpf_link__destroy(link);
249 bpf_object__close(obj);
250 return 0;
251 }
252
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