[PATCH 3/4] ACPI C-States: accounting of sleep times

[Dominik Brodowski <linux@dominikbrodowski.net>]

Also track the actual time spent in C-States (C2 upwards, we can't
determine this for C1), not only the number of invocations. This is
especially useful for dynamic ticks / "tickless systems", but is also
of interest on normal systems, as any interrupt activity leads to
C-States being exited, not only the timer interrupt.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

Index: working-tree/drivers/acpi/processor_idle.c
===================================================================
--- working-tree.orig/drivers/acpi/processor_idle.c
+++ working-tree/drivers/acpi/processor_idle.c
@@ -280,8 +280,6 @@ static void acpi_processor_idle(void)
 		cx = &pr->power.states[ACPI_STATE_C1];
 #endif
 
-	cx->usage++;
-
 	/*
 	 * Sleep:
 	 * ------
@@ -379,6 +377,9 @@ static void acpi_processor_idle(void)
 		local_irq_enable();
 		return;
 	}
+	cx->usage++;
+	if ((cx->type != ACPI_STATE_C1) && (sleep_ticks > 0))
+		cx->time += sleep_ticks;
 
 	next_state = pr->power.state;
 
@@ -993,9 +994,10 @@ static int acpi_processor_power_seq_show
 		else
 			seq_puts(seq, "demotion[--] ");
 
-		seq_printf(seq, "latency[%03d] usage[%08d]\n",
+		seq_printf(seq, "latency[%03d] usage[%08d] duration[%020llu]\n",
 			   pr->power.states[i].latency,
-			   pr->power.states[i].usage);
+			   pr->power.states[i].usage,
+			   pr->power.states[i].time);
 	}
 
       end:
Index: working-tree/include/acpi/processor.h
===================================================================
--- working-tree.orig/include/acpi/processor.h
+++ working-tree/include/acpi/processor.h
@@ -51,6 +51,7 @@ struct acpi_processor_cx {
 	u32 latency_ticks;
 	u32 power;
 	u32 usage;
+	u64 time;
 	struct acpi_processor_cx_policy promotion;
 	struct acpi_processor_cx_policy demotion;
 };