sched, lockdep: inline double_unlock_balance()

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We have a test case which measures the variation in the amount of time
needed to perform a fixed amount of work on the preempt_rt kernel. We
started seeing deterioration in it's performance recently. The test
should never take more than 10 microseconds, but we started 5-10%
failure rate.

Using elimination method, we traced the problem to commit
1b12bbc747 (lockdep: re-annotate
scheduler runqueues).

When LOCKDEP is disabled, this patch only adds an additional function
call to double_unlock_balance(). Hence I inlined double_unlock_balance()
and the problem went away. Here is a patch to make this change.

Signed-off-by: Sripathi Kodi <sripathik@in.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

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Sripathi Kodi 2008-11-05 18:57:14 +05:30 • committed by Ingo Molnar

parent e113a745f6

commit cf7f8690e8

2 changed files with 3 additions and 2 deletions

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kernel/sched.c

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3

kernel/sched_rt.c

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