Commit 56c7426b authored Sep 01, 2008 by Peter Zijlstra Committed by Ingo Molnar Sep 05, 2008

sched_clock: fix NOHZ interaction



If HLT stops the TSC, we'll fail to account idle time, thereby inflating the
actual process times. Fix this by re-calibrating the clock against GTOD when
leaving nohz mode.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Tested-by: Avi Kivity <avi@qumranet.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

parent b380b0d4

kernel/time/tick-sched.c

+3 −0

Original line number	Diff line number	Diff line
		@@ -162,6 +162,8 @@ void tick_nohz_stop_idle(int cpu)
		ts->idle_lastupdate = now;
		ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
		ts->idle_active = 0;

		sched_clock_idle_wakeup_event(0);
		}
		}

		@@ -177,6 +179,7 @@ static ktime_t tick_nohz_start_idle(struct tick_sched *ts)
		}
		ts->idle_entrytime = now;
		ts->idle_active = 1;
		sched_clock_idle_sleep_event();
		return now;
		}