From: Suresh Siddha <suresh.b.siddha@intel.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@elte.hu>, Venki Pallipadi <venki@google.com>,
Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>,
Mike Galbraith <efault@gmx.de>
Cc: linux-kernel <linux-kernel@vger.kernel.org>,
Tim Chen <tim.c.chen@linux.jf.intel.com>,
alex.shi@intel.com, Suresh Siddha <suresh.b.siddha@intel.com>
Subject: [patch 5/6] sched: disable sched feature TTWU_QUEUE by default
Date: Fri, 18 Nov 2011 15:03:28 -0800 [thread overview]
Message-ID: <20111118230554.105376150@sbsiddha-desk.sc.intel.com> (raw)
In-Reply-To: 20111118230323.592022417@sbsiddha-desk.sc.intel.com
[-- Attachment #1: disable_sched_ttwu_queue.patch --]
[-- Type: text/plain, Size: 1044 bytes --]
Context-switch intensive microbenchmark on a 8-socket system had
~600K times more resched IPI's on each logical CPU with this feature enabled
by default. Disabling this features makes that microbenchmark perform 5 times
better.
Also disabling this feature showed 2% performance improvement on a 8-socket
OLTP workload.
More heurestics are needed when and how to use this feature by default.
For now, disable it by default.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
---
kernel/sched/features.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
Index: tip/kernel/sched/features.h
===================================================================
--- tip.orig/kernel/sched/features.h
+++ tip/kernel/sched/features.h
@@ -64,7 +64,7 @@ SCHED_FEAT(NONTASK_POWER, 1)
* Queue remote wakeups on the target CPU and process them
* using the scheduler IPI. Reduces rq->lock contention/bounces.
*/
-SCHED_FEAT(TTWU_QUEUE, 1)
+SCHED_FEAT(TTWU_QUEUE, 0)
SCHED_FEAT(FORCE_SD_OVERLAP, 0)
SCHED_FEAT(RT_RUNTIME_SHARE, 1)
next prev parent reply other threads:[~2011-11-18 23:11 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-11-18 23:03 [patch 0/6] sched, nohz: load balancing patches Suresh Siddha
2011-11-18 23:03 ` [patch 1/6] sched, nohz: introduce nohz_flags in the struct rq Suresh Siddha
2011-11-24 10:24 ` Peter Zijlstra
2011-11-28 23:59 ` Suresh Siddha
2011-11-29 9:47 ` Peter Zijlstra
2011-11-18 23:03 ` [patch 2/6] sched, nohz: track nr_busy_cpus in the sched_group_power Suresh Siddha
2011-11-18 23:03 ` [patch 3/6] sched, nohz: sched group, domain aware nohz idle load balancing Suresh Siddha
2011-11-24 11:47 ` Peter Zijlstra
2011-11-28 23:51 ` Suresh Siddha
2011-11-29 9:44 ` Peter Zijlstra
2011-12-01 1:03 ` Suresh Siddha
2011-12-01 1:17 ` Suresh Siddha
2011-12-01 8:36 ` Peter Zijlstra
2011-11-24 11:53 ` Peter Zijlstra
2011-11-28 23:58 ` Suresh Siddha
2011-11-29 9:45 ` Peter Zijlstra
2011-11-18 23:03 ` [patch 4/6] sched, nohz: cleanup the find_new_ilb() using sched groups nr_busy_cpus Suresh Siddha
2011-11-18 23:03 ` Suresh Siddha [this message]
2011-11-19 4:30 ` [patch 5/6] sched: disable sched feature TTWU_QUEUE by default Mike Galbraith
2011-11-19 4:41 ` Mike Galbraith
2011-11-18 23:03 ` [patch 6/6] sched: fix the sched group node allocation for SD_OVERLAP domain Suresh Siddha
2011-12-06 9:51 ` [tip:sched/core] sched: Fix the sched group node allocation for SD_OVERLAP domains tip-bot for Suresh Siddha
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