Date: Thu, 20 Nov 2008 19:58:43 -0800
From: Keika Kobayashi <kobayashi.kk@ncos.nec.co.jp>
To: linux-kernel@vger.kernel.org, akpm@linux-foundation.org
Cc: h-shimamoto@ct.jp.nec.com
Subject: [PATCH 2/3] proc: Export statistics for softirq to /proc
Message-Id: <20081120195843.c6d0b653.kobayashi.kk@ncos.nec.co.jp>
In-Reply-To: <20081120195542.c85d4967.kobayashi.kk@ncos.nec.co.jp>
References: <20081120195542.c85d4967.kobayashi.kk@ncos.nec.co.jp>
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Export statistics for softirq in /proc/softirqs and /proc/stat.

1. /proc/softirqs
Implement /proc/softirqs which shows the number of softirq
for each CPU like /proc/interrupts.

2. /proc/stat
Add the "softirq" line to /proc/stat.
This line shows the number of softirq for all cpu.
The first column is the total of all softirqs and
each subsequent column is the total for particular softirq.

Signed-off-by: Keika Kobayashi <kobayashi.kk@ncos.nec.co.jp>
Reviewed-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
---
 fs/proc/Makefile          |    1 +
 fs/proc/softirqs.c        |   57 +++++++++++++++++++++++++++++++++++++++++++++
 fs/proc/stat.c            |   17 +++++++++++++
 include/linux/interrupt.h |    3 ++
 4 files changed, 78 insertions(+), 0 deletions(-)
 create mode 100644 fs/proc/softirqs.c

diff --git a/fs/proc/Makefile b/fs/proc/Makefile
index 63d9651..11a7b5c 100644
--- a/fs/proc/Makefile
+++ b/fs/proc/Makefile
@@ -18,6 +18,7 @@ proc-y	+= meminfo.o
 proc-y	+= stat.o
 proc-y	+= uptime.o
 proc-y	+= version.o
+proc-y	+= softirqs.o
 proc-$(CONFIG_PROC_SYSCTL)	+= proc_sysctl.o
 proc-$(CONFIG_NET)		+= proc_net.o
 proc-$(CONFIG_PROC_KCORE)	+= kcore.o
diff --git a/fs/proc/softirqs.c b/fs/proc/softirqs.c
new file mode 100644
index 0000000..43d3bc0
--- /dev/null
+++ b/fs/proc/softirqs.c
@@ -0,0 +1,57 @@
+#include <linux/init.h>
+#include <linux/kernel_stat.h>
+#include <linux/proc_fs.h>
+#include <linux/seq_file.h>
+
+static const char *desc_array[] = {
+	"HI",
+	"TIMER",
+	"NET_TX",
+	"NET_RX",
+	"BLOCK",
+	"TASKLET",
+	"SCHED",
+#ifdef CONFIG_HIGH_RES_TIMERS
+	"HRTIMER",
+#endif
+	"RCU"};
+
+/*
+ * /proc/softirqs  ... display the number of softirqs
+ */
+static int show_softirqs(struct seq_file *p, void *v)
+{
+	int i, j;
+
+	seq_printf(p, "                ");
+	for_each_online_cpu(i)
+		seq_printf(p, "CPU%-8d", i);
+	seq_printf(p, "\n");
+
+	for_each_softirq_nr(i) {
+		seq_printf(p, "%-10s", desc_array[i]);
+		for_each_online_cpu(j)
+			seq_printf(p, "%10u ", kstat_softirqs_cpu(i, j));
+		seq_printf(p, "\n");
+	}
+	return 0;
+}
+
+static int softirqs_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, show_softirqs, NULL);
+}
+
+static struct file_operations proc_softirqs_operations = {
+	.open		= softirqs_open,
+	.read		= seq_read,
+	.llseek		= seq_lseek,
+	.release	= single_release,
+};
+
+static int __init proc_softirqs_init(void)
+{
+	proc_create("softirqs", 0, NULL, &proc_softirqs_operations);
+	return 0;
+}
+module_init(proc_softirqs_init);
diff --git a/fs/proc/stat.c b/fs/proc/stat.c
index 81904f0..02d5bf8 100644
--- a/fs/proc/stat.c
+++ b/fs/proc/stat.c
@@ -25,6 +25,7 @@ static int show_stat(struct seq_file *p, void *v)
 	cputime64_t user, nice, system, idle, iowait, irq, softirq, steal;
 	cputime64_t guest;
 	u64 sum = 0;
+	u64 sum_softirq = 0;
 	struct timespec boottime;
 	unsigned int per_irq_sum;
 
@@ -49,6 +50,10 @@ static int show_stat(struct seq_file *p, void *v)
 			sum += kstat_irqs_cpu(j, i);
 
 		sum += arch_irq_stat_cpu(i);
+
+		for_each_softirq_nr(j)
+			sum_softirq += kstat_softirqs_cpu(j, i);
+
 	}
 	sum += arch_irq_stat();
 
@@ -111,6 +116,18 @@ static int show_stat(struct seq_file *p, void *v)
 		nr_running(),
 		nr_iowait());
 
+	seq_printf(p, "softirq %llu", (unsigned long long)sum_softirq);
+
+	for_each_softirq_nr(i) {
+		per_irq_sum = 0;
+
+		for_each_possible_cpu(j)
+			per_irq_sum += kstat_softirqs_cpu(i, j);
+
+		seq_printf(p, " %u", per_irq_sum);
+	}
+	seq_printf(p, "\n");
+
 	return 0;
 }
 
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index f58a0cf..9a12ba0 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -259,6 +259,9 @@ enum
 	NR_SOFTIRQS
 };
 
+#define for_each_softirq_nr(irq)		\
+	for (irq = 0; irq < NR_SOFTIRQS; irq++)
+
 /* softirq mask and active fields moved to irq_cpustat_t in
  * asm/hardirq.h to get better cache usage.  KAO
  */
-- 
1.5.0.6

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