Add irq and softirq time accounting to the kernel

fs/proc/proc_misc.c

@@ -362,7 +362,7 @@ static int kstat_read_proc(char *page, char **start, off_t off,
 	int i, len;
 	extern unsigned long total_forks;
 	u64 jif;
-	unsigned int sum = 0, user = 0, nice = 0, system = 0, idle = 0, iowait = 0;
+	unsigned int sum = 0, user = 0, nice = 0, system = 0, idle = 0, iowait = 0, irq = 0, softirq = 0;
 	struct timeval now; 
 	unsigned long seq;
 
@@ -388,25 +388,31 @@ static int kstat_read_proc(char *page, char **start, off_t off,
 		system += kstat_cpu(i).cpustat.system;
 		idle += kstat_cpu(i).cpustat.idle;
 		iowait += kstat_cpu(i).cpustat.iowait;
+		irq += kstat_cpu(i).cpustat.irq;
+		softirq += kstat_cpu(i).cpustat.softirq;
 		for (j = 0 ; j < NR_IRQS ; j++)
 			sum += kstat_cpu(i).irqs[j];
 	}
 
-	len = sprintf(page, "cpu  %u %u %u %u %u\n",
+	len = sprintf(page, "cpu  %u %u %u %u %u %u %u\n",
 		jiffies_to_clock_t(user),
 		jiffies_to_clock_t(nice),
 		jiffies_to_clock_t(system),
 		jiffies_to_clock_t(idle),
-		jiffies_to_clock_t(iowait));
+		jiffies_to_clock_t(iowait),
+		jiffies_to_clock_t(irq),
+		jiffies_to_clock_t(softirq));
 	for (i = 0 ; i < NR_CPUS; i++){
 		if (!cpu_online(i)) continue;
-		len += sprintf(page + len, "cpu%d %u %u %u %u %u\n",
+		len += sprintf(page + len, "cpu%d %u %u %u %u %u %u %u\n",
 			i,
 			jiffies_to_clock_t(kstat_cpu(i).cpustat.user),
 			jiffies_to_clock_t(kstat_cpu(i).cpustat.nice),
 			jiffies_to_clock_t(kstat_cpu(i).cpustat.system),
 			jiffies_to_clock_t(kstat_cpu(i).cpustat.idle),
-			jiffies_to_clock_t(kstat_cpu(i).cpustat.iowait));
+			jiffies_to_clock_t(kstat_cpu(i).cpustat.iowait),
+			jiffies_to_clock_t(kstat_cpu(i).cpustat.irq),
+			jiffies_to_clock_t(kstat_cpu(i).cpustat.softirq));
 	}
 	len += sprintf(page + len, "intr %u", sum);
 

include/linux/kernel_stat.h

@@ -17,6 +17,8 @@ struct cpu_usage_stat {
 	unsigned int user;
 	unsigned int nice;
 	unsigned int system;
+	unsigned int softirq;
+	unsigned int irq;
 	unsigned int idle;
 	unsigned int iowait;
 };

kernel/sched.c

@@ -1201,11 +1201,17 @@ void scheduler_tick(int user_ticks, int sys_ticks)
 	if (rcu_pending(cpu))
 		rcu_check_callbacks(cpu, user_ticks);
 
+	/* note: this timer irq context must be accounted for as well */
+	if (hardirq_count() - HARDIRQ_OFFSET) {
+		cpustat->irq += sys_ticks;
+		sys_ticks = 0;
+	} else if (softirq_count()) {
+		cpustat->softirq += sys_ticks;
+		sys_ticks = 0;
+	}
+
 	if (p == rq->idle) {
-		/* note: this timer irq context must be accounted for as well */
-		if (irq_count() - HARDIRQ_OFFSET >= SOFTIRQ_OFFSET)
-			cpustat->system += sys_ticks;
-		else if (atomic_read(&rq->nr_iowait) > 0)
+		if (atomic_read(&rq->nr_iowait) > 0)
 			cpustat->iowait += sys_ticks;
 		else
 			cpustat->idle += sys_ticks;