mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-17 01:04:19 +08:00
a130e8fbc7
/proc/uptime reports idle time by reading the CPUTIME_IDLE field from
the per-cpu kcpustats. However, on NO_HZ systems, idle time is not
continually updated on idle cpus, leading this value to appear
incorrectly small.
/proc/stat performs an accounting update when reading idle time; we
can use the same approach for uptime.
With this patch, /proc/stat and /proc/uptime now agree on idle time.
Additionally, the following shows idle time tick up consistently on an
idle machine:
(while true; do cat /proc/uptime; sleep 1; done) | awk '{print $2-prev; prev=$2}'
Reported-by: Luigi Rizzo <lrizzo@google.com>
Signed-off-by: Josh Don <joshdon@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lkml.kernel.org/r/20210827165438.3280779-1-joshdon@google.com
243 lines
6.2 KiB
C
243 lines
6.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
#include <linux/cpumask.h>
|
|
#include <linux/fs.h>
|
|
#include <linux/init.h>
|
|
#include <linux/interrupt.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/sched.h>
|
|
#include <linux/sched/stat.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/time.h>
|
|
#include <linux/time_namespace.h>
|
|
#include <linux/irqnr.h>
|
|
#include <linux/sched/cputime.h>
|
|
#include <linux/tick.h>
|
|
|
|
#ifndef arch_irq_stat_cpu
|
|
#define arch_irq_stat_cpu(cpu) 0
|
|
#endif
|
|
#ifndef arch_irq_stat
|
|
#define arch_irq_stat() 0
|
|
#endif
|
|
|
|
#ifdef arch_idle_time
|
|
|
|
u64 get_idle_time(struct kernel_cpustat *kcs, int cpu)
|
|
{
|
|
u64 idle;
|
|
|
|
idle = kcs->cpustat[CPUTIME_IDLE];
|
|
if (cpu_online(cpu) && !nr_iowait_cpu(cpu))
|
|
idle += arch_idle_time(cpu);
|
|
return idle;
|
|
}
|
|
|
|
static u64 get_iowait_time(struct kernel_cpustat *kcs, int cpu)
|
|
{
|
|
u64 iowait;
|
|
|
|
iowait = kcs->cpustat[CPUTIME_IOWAIT];
|
|
if (cpu_online(cpu) && nr_iowait_cpu(cpu))
|
|
iowait += arch_idle_time(cpu);
|
|
return iowait;
|
|
}
|
|
|
|
#else
|
|
|
|
u64 get_idle_time(struct kernel_cpustat *kcs, int cpu)
|
|
{
|
|
u64 idle, idle_usecs = -1ULL;
|
|
|
|
if (cpu_online(cpu))
|
|
idle_usecs = get_cpu_idle_time_us(cpu, NULL);
|
|
|
|
if (idle_usecs == -1ULL)
|
|
/* !NO_HZ or cpu offline so we can rely on cpustat.idle */
|
|
idle = kcs->cpustat[CPUTIME_IDLE];
|
|
else
|
|
idle = idle_usecs * NSEC_PER_USEC;
|
|
|
|
return idle;
|
|
}
|
|
|
|
static u64 get_iowait_time(struct kernel_cpustat *kcs, int cpu)
|
|
{
|
|
u64 iowait, iowait_usecs = -1ULL;
|
|
|
|
if (cpu_online(cpu))
|
|
iowait_usecs = get_cpu_iowait_time_us(cpu, NULL);
|
|
|
|
if (iowait_usecs == -1ULL)
|
|
/* !NO_HZ or cpu offline so we can rely on cpustat.iowait */
|
|
iowait = kcs->cpustat[CPUTIME_IOWAIT];
|
|
else
|
|
iowait = iowait_usecs * NSEC_PER_USEC;
|
|
|
|
return iowait;
|
|
}
|
|
|
|
#endif
|
|
|
|
static void show_irq_gap(struct seq_file *p, unsigned int gap)
|
|
{
|
|
static const char zeros[] = " 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0";
|
|
|
|
while (gap > 0) {
|
|
unsigned int inc;
|
|
|
|
inc = min_t(unsigned int, gap, ARRAY_SIZE(zeros) / 2);
|
|
seq_write(p, zeros, 2 * inc);
|
|
gap -= inc;
|
|
}
|
|
}
|
|
|
|
static void show_all_irqs(struct seq_file *p)
|
|
{
|
|
unsigned int i, next = 0;
|
|
|
|
for_each_active_irq(i) {
|
|
show_irq_gap(p, i - next);
|
|
seq_put_decimal_ull(p, " ", kstat_irqs_usr(i));
|
|
next = i + 1;
|
|
}
|
|
show_irq_gap(p, nr_irqs - next);
|
|
}
|
|
|
|
static int show_stat(struct seq_file *p, void *v)
|
|
{
|
|
int i, j;
|
|
u64 user, nice, system, idle, iowait, irq, softirq, steal;
|
|
u64 guest, guest_nice;
|
|
u64 sum = 0;
|
|
u64 sum_softirq = 0;
|
|
unsigned int per_softirq_sums[NR_SOFTIRQS] = {0};
|
|
struct timespec64 boottime;
|
|
|
|
user = nice = system = idle = iowait =
|
|
irq = softirq = steal = 0;
|
|
guest = guest_nice = 0;
|
|
getboottime64(&boottime);
|
|
/* shift boot timestamp according to the timens offset */
|
|
timens_sub_boottime(&boottime);
|
|
|
|
for_each_possible_cpu(i) {
|
|
struct kernel_cpustat kcpustat;
|
|
u64 *cpustat = kcpustat.cpustat;
|
|
|
|
kcpustat_cpu_fetch(&kcpustat, i);
|
|
|
|
user += cpustat[CPUTIME_USER];
|
|
nice += cpustat[CPUTIME_NICE];
|
|
system += cpustat[CPUTIME_SYSTEM];
|
|
idle += get_idle_time(&kcpustat, i);
|
|
iowait += get_iowait_time(&kcpustat, i);
|
|
irq += cpustat[CPUTIME_IRQ];
|
|
softirq += cpustat[CPUTIME_SOFTIRQ];
|
|
steal += cpustat[CPUTIME_STEAL];
|
|
guest += cpustat[CPUTIME_GUEST];
|
|
guest_nice += cpustat[CPUTIME_GUEST_NICE];
|
|
sum += kstat_cpu_irqs_sum(i);
|
|
sum += arch_irq_stat_cpu(i);
|
|
|
|
for (j = 0; j < NR_SOFTIRQS; j++) {
|
|
unsigned int softirq_stat = kstat_softirqs_cpu(j, i);
|
|
|
|
per_softirq_sums[j] += softirq_stat;
|
|
sum_softirq += softirq_stat;
|
|
}
|
|
}
|
|
sum += arch_irq_stat();
|
|
|
|
seq_put_decimal_ull(p, "cpu ", nsec_to_clock_t(user));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(system));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice));
|
|
seq_putc(p, '\n');
|
|
|
|
for_each_online_cpu(i) {
|
|
struct kernel_cpustat kcpustat;
|
|
u64 *cpustat = kcpustat.cpustat;
|
|
|
|
kcpustat_cpu_fetch(&kcpustat, i);
|
|
|
|
/* Copy values here to work around gcc-2.95.3, gcc-2.96 */
|
|
user = cpustat[CPUTIME_USER];
|
|
nice = cpustat[CPUTIME_NICE];
|
|
system = cpustat[CPUTIME_SYSTEM];
|
|
idle = get_idle_time(&kcpustat, i);
|
|
iowait = get_iowait_time(&kcpustat, i);
|
|
irq = cpustat[CPUTIME_IRQ];
|
|
softirq = cpustat[CPUTIME_SOFTIRQ];
|
|
steal = cpustat[CPUTIME_STEAL];
|
|
guest = cpustat[CPUTIME_GUEST];
|
|
guest_nice = cpustat[CPUTIME_GUEST_NICE];
|
|
seq_printf(p, "cpu%d", i);
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(user));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(nice));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(system));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(idle));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(iowait));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(irq));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(softirq));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(steal));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest));
|
|
seq_put_decimal_ull(p, " ", nsec_to_clock_t(guest_nice));
|
|
seq_putc(p, '\n');
|
|
}
|
|
seq_put_decimal_ull(p, "intr ", (unsigned long long)sum);
|
|
|
|
show_all_irqs(p);
|
|
|
|
seq_printf(p,
|
|
"\nctxt %llu\n"
|
|
"btime %llu\n"
|
|
"processes %lu\n"
|
|
"procs_running %u\n"
|
|
"procs_blocked %u\n",
|
|
nr_context_switches(),
|
|
(unsigned long long)boottime.tv_sec,
|
|
total_forks,
|
|
nr_running(),
|
|
nr_iowait());
|
|
|
|
seq_put_decimal_ull(p, "softirq ", (unsigned long long)sum_softirq);
|
|
|
|
for (i = 0; i < NR_SOFTIRQS; i++)
|
|
seq_put_decimal_ull(p, " ", per_softirq_sums[i]);
|
|
seq_putc(p, '\n');
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int stat_open(struct inode *inode, struct file *file)
|
|
{
|
|
unsigned int size = 1024 + 128 * num_online_cpus();
|
|
|
|
/* minimum size to display an interrupt count : 2 bytes */
|
|
size += 2 * nr_irqs;
|
|
return single_open_size(file, show_stat, NULL, size);
|
|
}
|
|
|
|
static const struct proc_ops stat_proc_ops = {
|
|
.proc_flags = PROC_ENTRY_PERMANENT,
|
|
.proc_open = stat_open,
|
|
.proc_read_iter = seq_read_iter,
|
|
.proc_lseek = seq_lseek,
|
|
.proc_release = single_release,
|
|
};
|
|
|
|
static int __init proc_stat_init(void)
|
|
{
|
|
proc_create("stat", 0, NULL, &stat_proc_ops);
|
|
return 0;
|
|
}
|
|
fs_initcall(proc_stat_init);
|