kernel: Measure time spent in interrupt handlers

headers/private/kernel/cpu.h

@@ -60,6 +60,8 @@ typedef struct cpu_ent {
 
 	// keeping track of CPU activity
 	bigtime_t		active_time;
+	bigtime_t		irq_time;
+	bigtime_t		interrupt_time;
 	bigtime_t		last_kernel_time;
 	bigtime_t		last_user_time;
 

src/system/kernel/int.cpp

@@ -243,6 +243,10 @@ int_io_interrupt_handler(int vector, bool levelTriggered)
 
 	bigtime_t start = system_time();
 
+	// exceptions and syscalls have their own handlers
+	ASSERT(sVectors[vector].type != INTERRUPT_TYPE_EXCEPTION
+		&& sVectors[vector].type != INTERRUPT_TYPE_SYSCALL);
+
 	if (!sVectors[vector].no_lock_vector)
 		acquire_spinlock(&sVectors[vector].vector_lock);
 
@@ -322,9 +326,13 @@ int_io_interrupt_handler(int vector, bool levelTriggered)
 		release_spinlock(&sVectors[vector].vector_lock);
 
 	SpinLocker locker(sVectors[vector].load_lock);
-	sVectors[vector].last_measure_active += system_time() - start;
+	bigtime_t deltaTime = system_time() - start;
+	sVectors[vector].last_measure_active += deltaTime;
 	locker.Unlock();
 
+	atomic_add64(&get_cpu_struct()->interrupt_time, deltaTime);
+	if (sVectors[vector].type == INTERRUPT_TYPE_IRQ)
+		atomic_add64(&get_cpu_struct()->irq_time, deltaTime);
 	update_int_load(vector);
 
 	if (levelTriggered)

src/system/kernel/system_info.cpp

@@ -50,10 +50,12 @@ dump_info(int argc, char **argv)
 		__VERSION__);
 	kprintf("revision: %s\n\n", get_haiku_revision());
 
-	kprintf("cpu count: %" B_PRId32 ", active times:\n", smp_get_num_cpus());
+	kprintf("cpu count: %" B_PRId32 "\n", smp_get_num_cpus());
 
 	for (int32 i = 0; i < smp_get_num_cpus(); i++)
-		kprintf("  [%" B_PRId32 "] %" B_PRId64 "\n", i + 1, gCPU[i].active_time);
+		kprintf("  [%" B_PRId32 "] active time: %12" B_PRId64 ", interrupt"
+			" time: %12" B_PRId64 ", irq time: %12" B_PRId64 "\n", i + 1,
+			gCPU[i].active_time, gCPU[i].interrupt_time, gCPU[i].irq_time);
 
 	// ToDo: Add page_faults
 	kprintf("pages:\t\t%" B_PRIuPHYSADDR " (%" B_PRIuPHYSADDR " max)\n",