sched: debug: track maximum 'slice'

track the maximum amount of time a task has executed while
the CPU load was at least 2x. (i.e. at least two nice-0
tasks were runnable)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 94915f1..fd080f6 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -254,6 +254,7 @@
 	P(se.sleep_max);
 	P(se.block_max);
 	P(se.exec_max);
+	P(se.slice_max);
 	P(se.wait_max);
 	P(se.wait_runtime_overruns);
 	P(se.wait_runtime_underruns);
@@ -282,6 +283,7 @@
 	p->se.sleep_max			= 0;
 	p->se.block_max			= 0;
 	p->se.exec_max			= 0;
+	p->se.slice_max			= 0;
 	p->se.wait_max			= 0;
 	p->se.wait_runtime_overruns	= 0;
 	p->se.wait_runtime_underruns	= 0;