30 lines
1.1 KiB
Diff
30 lines
1.1 KiB
Diff
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# Commit 054b6dfb61eab00d86ddd5d0ac508f5302da0d52
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# Date 2014-05-28 10:07:50 +0200
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# Author Ross Lagerwall <ross.lagerwall@citrix.com>
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# Committer Jan Beulich <jbeulich@suse.com>
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timers: set the deadline more accurately
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Program the timer to the deadline of the closest timer if it is further
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than 50us ahead, otherwise set it 50us ahead. This way a single event
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fires on time rather than 50us late (as it would have previously) while
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still preventing too many timer wakeups in the case of having many
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timers scheduled close together.
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(where 50us is the timer_slop)
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Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
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--- a/xen/common/timer.c
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+++ b/xen/common/timer.c
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@@ -492,8 +492,9 @@ static void timer_softirq_action(void)
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deadline = heap[1]->expires;
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if ( (ts->list != NULL) && (ts->list->expires < deadline) )
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deadline = ts->list->expires;
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+ now = NOW();
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this_cpu(timer_deadline) =
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- (deadline == STIME_MAX) ? 0 : deadline + timer_slop;
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+ (deadline == STIME_MAX) ? 0 : MAX(deadline, now + timer_slop);
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if ( !reprogram_timer(this_cpu(timer_deadline)) )
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raise_softirq(TIMER_SOFTIRQ);
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