linux-kernel - [PATCH 3/3] sched: Disable affine wakeups by default

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Date:	Sat, 24 Oct 2009 13:07:28 -0700
From:	Arjan van de Ven <arjan@...radead.org>
To:	Arjan van de Ven <arjan@...radead.org>
Cc:	Peter Zijlstra <peterz@...radead.org>, mingo@...e.hu,
	linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] sched: Disable affine wakeups by default

Subject: sched: Disable affine wakeups by default
From: Arjan van de Ven <arjan@...ux.intel.com>

The global affine wakeup scheduler feature sounds nice, but there is a problem
with this: This is ALSO a per scheduler domain feature already.
By having the global scheduler feature enabled by default, the scheduler domains
no longer have the option to opt out.

There are domains (for example the HT/SMT domain) that have good reason to want
to opt out of this feature.

With this patch they can opt out, while all other domains currently default to
the affine setting anyway.

Signed-off-by: Arjan van de Ven <arjan@...ux.intel.com>

diff --git a/kernel/sched_features.h b/kernel/sched_features.h
index 0d94083..58c2ea7 100644
--- a/kernel/sched_features.h
+++ b/kernel/sched_features.h
@@ -72,7 +72,7 @@ SCHED_FEAT(SYNC_WAKEUPS, 1)
  * improve cache locality. Typically used with SYNC wakeups as
  * generated by pipes and the like, see also SYNC_WAKEUPS.
  */
-SCHED_FEAT(AFFINE_WAKEUPS, 1)
+SCHED_FEAT(AFFINE_WAKEUPS, 0)
 
 /*
  * Weaken SYNC hint based on overlap



-- 
Arjan van de Ven 	Intel Open Source Technology Centre
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