xref: /openbmc/linux/fs/proc/stat.c (revision 0c874100)
1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/cpumask.h>
3 #include <linux/fs.h>
4 #include <linux/init.h>
5 #include <linux/interrupt.h>
6 #include <linux/kernel_stat.h>
7 #include <linux/proc_fs.h>
8 #include <linux/sched.h>
9 #include <linux/sched/stat.h>
10 #include <linux/seq_file.h>
11 #include <linux/slab.h>
12 #include <linux/time.h>
13 #include <linux/irqnr.h>
14 #include <linux/sched/cputime.h>
15 #include <linux/tick.h>
16 
17 #ifndef arch_irq_stat_cpu
18 #define arch_irq_stat_cpu(cpu) 0
19 #endif
20 #ifndef arch_irq_stat
21 #define arch_irq_stat() 0
22 #endif
23 
24 #ifdef arch_idle_time
25 
26 static u64 get_idle_time(int cpu)
27 {
28 	u64 idle;
29 
30 	idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE];
31 	if (cpu_online(cpu) && !nr_iowait_cpu(cpu))
32 		idle += arch_idle_time(cpu);
33 	return idle;
34 }
35 
36 static u64 get_iowait_time(int cpu)
37 {
38 	u64 iowait;
39 
40 	iowait = kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT];
41 	if (cpu_online(cpu) && nr_iowait_cpu(cpu))
42 		iowait += arch_idle_time(cpu);
43 	return iowait;
44 }
45 
46 #else
47 
48 static u64 get_idle_time(int cpu)
49 {
50 	u64 idle, idle_usecs = -1ULL;
51 
52 	if (cpu_online(cpu))
53 		idle_usecs = get_cpu_idle_time_us(cpu, NULL);
54 
55 	if (idle_usecs == -1ULL)
56 		/* !NO_HZ or cpu offline so we can rely on cpustat.idle */
57 		idle = kcpustat_cpu(cpu).cpustat[CPUTIME_IDLE];
58 	else
59 		idle = idle_usecs * NSEC_PER_USEC;
60 
61 	return idle;
62 }
63 
64 static u64 get_iowait_time(int cpu)
65 {
66 	u64 iowait, iowait_usecs = -1ULL;
67 
68 	if (cpu_online(cpu))
69 		iowait_usecs = get_cpu_iowait_time_us(cpu, NULL);
70 
71 	if (iowait_usecs == -1ULL)
72 		/* !NO_HZ or cpu offline so we can rely on cpustat.iowait */
73 		iowait = kcpustat_cpu(cpu).cpustat[CPUTIME_IOWAIT];
74 	else
75 		iowait = iowait_usecs * NSEC_PER_USEC;
76 
77 	return iowait;
78 }
79 
80 #endif
81 
82 static int show_stat(struct seq_file *p, void *v)
83 {
84 	int i, j;
85 	u64 user, nice, system, idle, iowait, irq, softirq, steal;
86 	u64 guest, guest_nice;
87 	u64 sum = 0;
88 	u64 sum_softirq = 0;
89 	unsigned int per_softirq_sums[NR_SOFTIRQS] = {0};
90 	struct timespec64 boottime;
91 
92 	user = nice = system = idle = iowait =
93 		irq = softirq = steal = 0;
94 	guest = guest_nice = 0;
95 	getboottime64(&boottime);
96 
97 	for_each_possible_cpu(i) {
98 		user += kcpustat_cpu(i).cpustat[CPUTIME_USER];
99 		nice += kcpustat_cpu(i).cpustat[CPUTIME_NICE];
100 		system += kcpustat_cpu(i).cpustat[CPUTIME_SYSTEM];
101 		idle += get_idle_time(i);
102 		iowait += get_iowait_time(i);
103 		irq += kcpustat_cpu(i).cpustat[CPUTIME_IRQ];
104 		softirq += kcpustat_cpu(i).cpustat[CPUTIME_SOFTIRQ];
105 		steal += kcpustat_cpu(i).cpustat[CPUTIME_STEAL];
106 		guest += kcpustat_cpu(i).cpustat[CPUTIME_GUEST];
107 		guest_nice += kcpustat_cpu(i).cpustat[CPUTIME_GUEST_NICE];
108 		sum += kstat_cpu_irqs_sum(i);
109 		sum += arch_irq_stat_cpu(i);
110 
111 		for (j = 0; j < NR_SOFTIRQS; j++) {
112 			unsigned int softirq_stat = kstat_softirqs_cpu(j, i);
113 
114 			per_softirq_sums[j] += softirq_stat;
115 			sum_softirq += softirq_stat;
116 		}
117 	}
118 	sum += arch_irq_stat();
119 
120 	seq_put_decimal_ull(p, "cpu  ", nsec_to_clock_t(user));
121 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
122 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(system));
123 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle));
124 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait));
125 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq));
126 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq));
127 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal));
128 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest));
129 	seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice));
130 	seq_putc(p, '\n');
131 
132 	for_each_online_cpu(i) {
133 		/* Copy values here to work around gcc-2.95.3, gcc-2.96 */
134 		user = kcpustat_cpu(i).cpustat[CPUTIME_USER];
135 		nice = kcpustat_cpu(i).cpustat[CPUTIME_NICE];
136 		system = kcpustat_cpu(i).cpustat[CPUTIME_SYSTEM];
137 		idle = get_idle_time(i);
138 		iowait = get_iowait_time(i);
139 		irq = kcpustat_cpu(i).cpustat[CPUTIME_IRQ];
140 		softirq = kcpustat_cpu(i).cpustat[CPUTIME_SOFTIRQ];
141 		steal = kcpustat_cpu(i).cpustat[CPUTIME_STEAL];
142 		guest = kcpustat_cpu(i).cpustat[CPUTIME_GUEST];
143 		guest_nice = kcpustat_cpu(i).cpustat[CPUTIME_GUEST_NICE];
144 		seq_printf(p, "cpu%d", i);
145 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(user));
146 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
147 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(system));
148 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle));
149 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait));
150 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq));
151 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq));
152 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal));
153 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest));
154 		seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice));
155 		seq_putc(p, '\n');
156 	}
157 	seq_put_decimal_ull(p, "intr ", (unsigned long long)sum);
158 
159 	/* sum again ? it could be updated? */
160 	for_each_irq_nr(j)
161 		seq_put_decimal_ull(p, " ", kstat_irqs_usr(j));
162 
163 	seq_printf(p,
164 		"\nctxt %llu\n"
165 		"btime %llu\n"
166 		"processes %lu\n"
167 		"procs_running %lu\n"
168 		"procs_blocked %lu\n",
169 		nr_context_switches(),
170 		(unsigned long long)boottime.tv_sec,
171 		total_forks,
172 		nr_running(),
173 		nr_iowait());
174 
175 	seq_put_decimal_ull(p, "softirq ", (unsigned long long)sum_softirq);
176 
177 	for (i = 0; i < NR_SOFTIRQS; i++)
178 		seq_put_decimal_ull(p, " ", per_softirq_sums[i]);
179 	seq_putc(p, '\n');
180 
181 	return 0;
182 }
183 
184 static int stat_open(struct inode *inode, struct file *file)
185 {
186 	unsigned int size = 1024 + 128 * num_online_cpus();
187 
188 	/* minimum size to display an interrupt count : 2 bytes */
189 	size += 2 * nr_irqs;
190 	return single_open_size(file, show_stat, NULL, size);
191 }
192 
193 static const struct file_operations proc_stat_operations = {
194 	.open		= stat_open,
195 	.read		= seq_read,
196 	.llseek		= seq_lseek,
197 	.release	= single_release,
198 };
199 
200 static int __init proc_stat_init(void)
201 {
202 	proc_create("stat", 0, NULL, &proc_stat_operations);
203 	return 0;
204 }
205 fs_initcall(proc_stat_init);
206