aa0ce5bbc2
Statistics for softirq doesn't exist.
It will be helpful like statistics for interrupts.
This patch introduces counting the number of softirq,
which will be exported in /proc/softirqs.
When softirq handler consumes much CPU time,
/proc/stat is like the following.
$ while :; do cat /proc/stat | head -n1 ; sleep 10 ; done
cpu 88 0 408 739665 583 28 2 0 0
cpu 450 0 1090 740970 594 28 1294 0 0
^^^^
softirq
In such a situation,
/proc/softirqs shows us which softirq handler is invoked.
We can see the increase rate of softirqs.
<before>
$ cat /proc/softirqs
CPU0 CPU1 CPU2 CPU3
HI 0 0 0 0
TIMER 462850 462805 462782 462718
NET_TX 0 0 0 365
NET_RX 2472 2 2 40
BLOCK 0 0 381 1164
TASKLET 0 0 0 224
SCHED 462654 462689 462698 462427
RCU 3046 2423 3367 3173
<after>
$ cat /proc/softirqs
CPU0 CPU1 CPU2 CPU3
HI 0 0 0 0
TIMER 463361 465077 465056 464991
NET_TX 53 0 1 365
NET_RX 3757 2 2 40
BLOCK 0 0 398 1170
TASKLET 0 0 0 224
SCHED 463074 464318 464612 463330
RCU 3505 2948 3947 3673
When CPU TIME of softirq is high,
the rates of increase is the following.
TIMER : 220/sec : CPU1-3
NET_TX : 5/sec : CPU0
NET_RX : 120/sec : CPU0
SCHED : 40-200/sec : all CPU
RCU : 45-58/sec : all CPU
The rates of increase in an idle mode is the following.
TIMER : 250/sec
SCHED : 250/sec
RCU : 2/sec
It seems many softirqs for receiving packets and rcu are invoked. This
gives us help for checking system.
Signed-off-by: Keika Kobayashi <kobayashi.kk@ncos.nec.co.jp>
Reviewed-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Eric Dumazet <dada1@cosmosbay.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
111 lines
2.6 KiB
C
111 lines
2.6 KiB
C
#ifndef _LINUX_KERNEL_STAT_H
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#define _LINUX_KERNEL_STAT_H
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#include <linux/smp.h>
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#include <linux/threads.h>
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#include <linux/percpu.h>
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#include <linux/cpumask.h>
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#include <linux/interrupt.h>
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#include <asm/irq.h>
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#include <asm/cputime.h>
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/*
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* 'kernel_stat.h' contains the definitions needed for doing
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* some kernel statistics (CPU usage, context switches ...),
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* used by rstatd/perfmeter
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*/
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struct cpu_usage_stat {
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cputime64_t user;
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cputime64_t nice;
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cputime64_t system;
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cputime64_t softirq;
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cputime64_t irq;
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cputime64_t idle;
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cputime64_t iowait;
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cputime64_t steal;
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cputime64_t guest;
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};
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struct kernel_stat {
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struct cpu_usage_stat cpustat;
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#ifndef CONFIG_GENERIC_HARDIRQS
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unsigned int irqs[NR_IRQS];
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#endif
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unsigned int softirqs[NR_SOFTIRQS];
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};
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DECLARE_PER_CPU(struct kernel_stat, kstat);
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#define kstat_cpu(cpu) per_cpu(kstat, cpu)
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/* Must have preemption disabled for this to be meaningful. */
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#define kstat_this_cpu __get_cpu_var(kstat)
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extern unsigned long long nr_context_switches(void);
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#ifndef CONFIG_GENERIC_HARDIRQS
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#define kstat_irqs_this_cpu(irq) \
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(kstat_this_cpu.irqs[irq])
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struct irq_desc;
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static inline void kstat_incr_irqs_this_cpu(unsigned int irq,
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struct irq_desc *desc)
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{
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kstat_this_cpu.irqs[irq]++;
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}
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static inline unsigned int kstat_irqs_cpu(unsigned int irq, int cpu)
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{
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return kstat_cpu(cpu).irqs[irq];
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}
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#else
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#include <linux/irq.h>
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extern unsigned int kstat_irqs_cpu(unsigned int irq, int cpu);
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#define kstat_irqs_this_cpu(DESC) \
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((DESC)->kstat_irqs[smp_processor_id()])
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#define kstat_incr_irqs_this_cpu(irqno, DESC) \
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((DESC)->kstat_irqs[smp_processor_id()]++)
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#endif
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static inline void kstat_incr_softirqs_this_cpu(unsigned int irq)
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{
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kstat_this_cpu.softirqs[irq]++;
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}
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static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu)
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{
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return kstat_cpu(cpu).softirqs[irq];
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}
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/*
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* Number of interrupts per specific IRQ source, since bootup
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*/
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static inline unsigned int kstat_irqs(unsigned int irq)
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{
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unsigned int sum = 0;
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int cpu;
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for_each_possible_cpu(cpu)
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sum += kstat_irqs_cpu(irq, cpu);
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return sum;
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}
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/*
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* Lock/unlock the current runqueue - to extract task statistics:
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*/
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extern unsigned long long task_delta_exec(struct task_struct *);
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extern void account_user_time(struct task_struct *, cputime_t, cputime_t);
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extern void account_system_time(struct task_struct *, int, cputime_t, cputime_t);
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extern void account_steal_time(cputime_t);
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extern void account_idle_time(cputime_t);
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extern void account_process_tick(struct task_struct *, int user);
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extern void account_steal_ticks(unsigned long ticks);
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extern void account_idle_ticks(unsigned long ticks);
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#endif /* _LINUX_KERNEL_STAT_H */
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