[gentoo-commits] linux-patches r1379 - genpatches-2.6/trunk/2.6.26

[Daniel Drake (dsd)]

Author: dsd
Date: 2008-11-19 11:12:26 +0000 (Wed, 19 Nov 2008)
New Revision: 1379

Added:
   genpatches-2.6/trunk/2.6.26/1800_sched-disable-hrtick.patch
Modified:
   genpatches-2.6/trunk/2.6.26/0000_README
Log:
Disable high-resolution scheduler ticks to avoid performance regression, thanks to Kerin Millar in bug #247453

Modified: genpatches-2.6/trunk/2.6.26/0000_README
===================================================================
--- genpatches-2.6/trunk/2.6.26/0000_README	2008-11-19 11:07:39 UTC (rev 1378)
+++ genpatches-2.6/trunk/2.6.26/0000_README	2008-11-19 11:12:26 UTC (rev 1379)
@@ -67,6 +67,10 @@
 From:	http://www.kernel.org
 Desc:	Adds missing capability checks in drivers/net/wan/sbni.c -> sbni_ioctl()
 
+Patch:	1800_sched-disable-hrtick.patch
+From:	http://bugs.gentoo.org/247453
+Desc:	Disable high-resolution scheduler ticks to avoid performance regression
+
 Patch:	1900_UTC-timestamp-option.patch
 From:	http://bugs.gentoo.org/233307
 Desc:	Fix to add UTC timestamp option

Added: genpatches-2.6/trunk/2.6.26/1800_sched-disable-hrtick.patch
===================================================================
--- genpatches-2.6/trunk/2.6.26/1800_sched-disable-hrtick.patch	                        (rev 0)
+++ genpatches-2.6/trunk/2.6.26/1800_sched-disable-hrtick.patch	2008-11-19 11:12:26 UTC (rev 1379)
@@ -0,0 +1,32 @@
+From: Ingo Molnar <mingo@××××.hu>
+Date: Mon, 20 Oct 2008 12:27:43 +0000 (+0200)
+Subject: sched: disable the hrtick for now
+X-Git-Tag: v2.6.28-rc1~43^2
+X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=0c4b83da58ec2e96ce9c44c211d6eac5f9dae478
+
+sched: disable the hrtick for now
+
+David Miller reported that hrtick update overhead has tripled the
+wakeup overhead on Sparc64.
+
+That is too much - disable the HRTICK feature for now by default,
+until a faster implementation is found.
+
+Reported-by: David Miller <davem@×××××××××.net>
+Acked-by: Peter Zijlstra <peterz@×××××××××.org>
+Signed-off-by: Ingo Molnar <mingo@××××.hu>
+---
+
+diff --git a/kernel/sched_features.h b/kernel/sched_features.h
+index 7c9e8f4..fda0162 100644
+--- a/kernel/sched_features.h
++++ b/kernel/sched_features.h
+@@ -5,7 +5,7 @@ SCHED_FEAT(START_DEBIT, 1)
+ SCHED_FEAT(AFFINE_WAKEUPS, 1)
+ SCHED_FEAT(CACHE_HOT_BUDDY, 1)
+ SCHED_FEAT(SYNC_WAKEUPS, 1)
+-SCHED_FEAT(HRTICK, 1)
++SCHED_FEAT(HRTICK, 0)
+ SCHED_FEAT(DOUBLE_TICK, 0)
+ SCHED_FEAT(ASYM_GRAN, 1)
+ SCHED_FEAT(LB_BIAS, 1)