Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755391AbYKUDzz (ORCPT ); Thu, 20 Nov 2008 22:55:55 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751793AbYKUDzp (ORCPT ); Thu, 20 Nov 2008 22:55:45 -0500 Received: from gateway-1237.mvista.com ([63.81.120.158]:38577 "EHLO gateway-1237.mvista.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751570AbYKUDzo (ORCPT ); Thu, 20 Nov 2008 22:55:44 -0500 Date: Thu, 20 Nov 2008 19:55:42 -0800 From: Keika Kobayashi To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org Cc: h-shimamoto@ct.jp.nec.com Subject: [PATCH 1/3] softirq: Introduce statistics for softirq Message-Id: <20081120195542.c85d4967.kobayashi.kk@ncos.nec.co.jp> X-Mailer: Sylpheed 2.4.8 (GTK+ 2.10.14; i686-pc-mingw32) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3899 Lines: 122 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. $ 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 $ 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 Reviewed-by: Hiroshi Shimamoto --- include/linux/kernel_stat.h | 12 ++++++++++++ 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 4a145ca..57c1643 100644 --- a/include/linux/kernel_stat.h +++ b/include/linux/kernel_stat.h @@ -5,6 +5,7 @@ #include #include #include +#include #include #include @@ -29,6 +30,7 @@ struct cpu_usage_stat { struct kernel_stat { struct cpu_usage_stat cpustat; unsigned int irqs[NR_IRQS]; + unsigned int softirqs[NR_SOFTIRQS]; }; DECLARE_PER_CPU(struct kernel_stat, kstat); @@ -52,6 +54,16 @@ static inline unsigned int kstat_irqs_cpu(unsigned int irq, int cpu) return kstat_cpu(cpu).irqs[irq]; } +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 e7c69a7..088e179 100644 --- a/kernel/softirq.c +++ b/kernel/softirq.c @@ -208,6 +208,7 @@ restart: do { if (pending & 1) { int prev_count = preempt_count(); + kstat_incr_softirqs_this_cpu(h - softirq_vec); h->action(h); -- 1.5.0.6 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/