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>

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>
Peter Zijlstra · Ingo Molnar
1 parent b380b0d4f7
Showing 1 changed file with 3 additions and 0 deletions Side-by-side Diff
kernel/time/tick-sched.c
@@ -162,6 +162,8 @@
 		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 @@
 	}
 	ts->idle_entrytime = now;
 	ts->idle_active = 1;
+	sched_clock_idle_sleep_event();
 	return now;
 }
...	...	@@ -162,6 +162,8 @@
162	162	ts->idle_lastupdate = now;
163	163	ts->idle_sleeptime = ktime_add(ts->idle_sleeptime, delta);
164	164	ts->idle_active = 0;
	165	+
	166	+ sched_clock_idle_wakeup_event(0);
165	167	}
166	168	}
167	169
...	...	@@ -177,6 +179,7 @@
177	179	}
178	180	ts->idle_entrytime = now;
179	181	ts->idle_active = 1;
	182	+ sched_clock_idle_sleep_event();
180	183	return now;
181	184	}
182	185