diff options
| author | Keika Kobayashi <kobayashi.kk@ncos.nec.co.jp> | 2009-06-18 03:25:52 +0400 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-06-19 00:03:40 +0400 |
| commit | aa0ce5bbc2dbb1853bd0c6d13f17716fcc38ac5a (patch) | |
| tree | 79efff8d1e52e3d1b968a5122447d25886ef29d7 | |
| parent | 1d89b30cc9be41af87881682ec82e2c107849dbe (diff) | |
| download | linux-aa0ce5bbc2dbb1853bd0c6d13f17716fcc38ac5a.tar.xz | |
softirq: introduce statistics for softirq
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>
| -rw-r--r-- | include/linux/kernel_stat.h | 12 | ||||
| -rw-r--r-- | kernel/softirq.c | 1 |
2 files changed, 13 insertions, 0 deletions
diff --git a/include/linux/kernel_stat.h b/include/linux/kernel_stat.h index a77c6007dc99..348fa8874b52 100644 --- a/include/linux/kernel_stat.h +++ b/include/linux/kernel_stat.h @@ -5,6 +5,7 @@ #include <linux/threads.h> #include <linux/percpu.h> #include <linux/cpumask.h> +#include <linux/interrupt.h> #include <asm/irq.h> #include <asm/cputime.h> @@ -31,6 +32,7 @@ struct kernel_stat { #ifndef CONFIG_GENERIC_HARDIRQS unsigned int irqs[NR_IRQS]; #endif + unsigned int softirqs[NR_SOFTIRQS]; }; DECLARE_PER_CPU(struct kernel_stat, kstat); @@ -67,6 +69,16 @@ extern unsigned int kstat_irqs_cpu(unsigned int irq, int cpu); #endif +static inline void kstat_incr_softirqs_this_cpu(unsigned int irq) +{ + kstat_this_cpu.softirqs[irq]++; +} + +static inline unsigned int kstat_softirqs_cpu(unsigned int irq, int cpu) +{ + return kstat_cpu(cpu).softirqs[irq]; +} + /* * Number of interrupts per specific IRQ source, since bootup */ diff --git a/kernel/softirq.c b/kernel/softirq.c index b41fb710e114..3a94905fa5d2 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -213,6 +213,7 @@ restart: do { if (pending & 1) { int prev_count = preempt_count(); + kstat_incr_softirqs_this_cpu(h - softirq_vec); trace_softirq_entry(h, softirq_vec); h->action(h); |