1 /*
2 * Copyright (c) 2024, Nordic Semiconductor ASA
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <zephyr/debug/cpu_load.h>
8 #include <zephyr/kernel.h>
9 #include <zephyr/drivers/counter.h>
10 #include <zephyr/logging/log.h>
11 LOG_MODULE_REGISTER(cpu_load);
12
13 BUILD_ASSERT(!IS_ENABLED(CONFIG_CPU_LOAD_USE_COUNTER) || DT_HAS_CHOSEN(zephyr_cpu_load_counter));
14
15 #ifndef CONFIG_CPU_LOAD_LOG_PERIODICALLY
16 #define CONFIG_CPU_LOAD_LOG_PERIODICALLY 0
17 #endif
18
19 const struct device *counter = COND_CODE_1(CONFIG_CPU_LOAD_USE_COUNTER,
20 (DEVICE_DT_GET(DT_CHOSEN(zephyr_cpu_load_counter))), (NULL));
21 static uint32_t enter_ts;
22 static uint32_t cyc_start;
23 static uint32_t ticks_idle;
24
25 static struct k_work_delayable cpu_load_log;
26
cpu_load_log_control(bool enable)27 void cpu_load_log_control(bool enable)
28 {
29 if (CONFIG_CPU_LOAD_LOG_PERIODICALLY == 0) {
30 return;
31 }
32
33 if (enable) {
34 (void)cpu_load_get(true);
35 k_work_schedule(&cpu_load_log, K_MSEC(CONFIG_CPU_LOAD_LOG_PERIODICALLY));
36 } else {
37 k_work_cancel_delayable(&cpu_load_log);
38 }
39 }
40
41 #if CONFIG_CPU_LOAD_USE_COUNTER || CONFIG_CPU_LOAD_LOG_PERIODICALLY
cpu_load_log_fn(struct k_work * work)42 static void cpu_load_log_fn(struct k_work *work)
43 {
44 int load = cpu_load_get(true);
45 uint32_t percent = load / 10;
46 uint32_t fraction = load % 10;
47
48 LOG_INF("Load:%d.%03d%%", percent, fraction);
49 cpu_load_log_control(true);
50 }
51
cpu_load_init(void)52 static int cpu_load_init(void)
53 {
54 if (IS_ENABLED(CONFIG_CPU_LOAD_USE_COUNTER)) {
55 int err = counter_start(counter);
56
57 (void)err;
58 __ASSERT_NO_MSG(err == 0);
59 }
60
61 if (CONFIG_CPU_LOAD_LOG_PERIODICALLY > 0) {
62 k_work_init_delayable(&cpu_load_log, cpu_load_log_fn);
63 return k_work_schedule(&cpu_load_log, K_MSEC(CONFIG_CPU_LOAD_LOG_PERIODICALLY));
64 }
65
66 return 0;
67 }
68
69 SYS_INIT(cpu_load_init, POST_KERNEL, 0);
70 #endif
71
cpu_load_on_enter_idle(void)72 void cpu_load_on_enter_idle(void)
73 {
74 if (IS_ENABLED(CONFIG_CPU_LOAD_USE_COUNTER)) {
75 counter_get_value(counter, &enter_ts);
76 return;
77 }
78
79 enter_ts = k_cycle_get_32();
80 }
81
cpu_load_on_exit_idle(void)82 void cpu_load_on_exit_idle(void)
83 {
84 uint32_t now;
85
86 if (IS_ENABLED(CONFIG_CPU_LOAD_USE_COUNTER)) {
87 counter_get_value(counter, &now);
88 } else {
89 now = k_cycle_get_32();
90 }
91
92 ticks_idle += now - enter_ts;
93 }
94
cpu_load_get(bool reset)95 int cpu_load_get(bool reset)
96 {
97 uint32_t idle_us;
98 uint32_t total = k_cycle_get_32() - cyc_start;
99 uint32_t total_us = (uint32_t)k_cyc_to_us_floor32(total);
100 uint32_t res;
101 uint32_t active_us;
102
103 if (IS_ENABLED(CONFIG_CPU_LOAD_USE_COUNTER)) {
104 idle_us = counter_ticks_to_us(counter, ticks_idle);
105 } else {
106 idle_us = k_cyc_to_us_floor32(ticks_idle);
107 }
108
109 idle_us = MIN(idle_us, total_us);
110 active_us = total_us - idle_us;
111
112 res = ((1000 * active_us) / total_us);
113
114 if (reset) {
115 cyc_start = k_cycle_get_32();
116 ticks_idle = 0;
117 }
118
119 return res;
120 }
121
