From 61eadef6a9bde9ea62fda724a9cb501ce9bc925a Mon Sep 17 00:00:00 2001 From: Mike Galbraith Date: Fri, 29 Apr 2011 08:36:50 +0200 Subject: sched, rt: Update rq clock when unthrottling of an otherwise idle CPU If an RT task is awakened while it's rt_rq is throttled, the time between wakeup/enqueue and unthrottle/selection may be accounted as rt_time if the CPU is idle. Set rq->skip_clock_update negative upon throttle release to tell put_prev_task() that we need a clock update. Reported-by: Thomas Giesel Signed-off-by: Mike Galbraith Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/1304059010.7472.1.camel@marge.simson.net Signed-off-by: Ingo Molnar --- kernel/sched_rt.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'kernel/sched_rt.c') diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 19ecb31..0943ed7 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -562,6 +562,13 @@ static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun) if (rt_rq->rt_throttled && rt_rq->rt_time < runtime) { rt_rq->rt_throttled = 0; enqueue = 1; + + /* + * Force a clock update if the CPU was idle, + * lest wakeup -> unthrottle time accumulate. + */ + if (rt_rq->rt_nr_running && rq->curr == rq->idle) + rq->skip_clock_update = -1; } if (rt_rq->rt_time || rt_rq->rt_nr_running) idle = 0; -- cgit v1.1