lkml.org 
[lkml]   [2008]   [Dec]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC PATCH v5 6/7] sched: add SD_BALANCE_NEWIDLE at MC and CPU level for sched_mc>0
Date
Add SD_BALANCE_NEWIDLE flag at MC level and CPU level
if sched_mc is set. This helps power savings and
will not affect performance when sched_mc=0

Ingo and Mike Galbraith have optimised the SD flags by
removing SD_BALANCE_NEWIDLE at MC and CPU level. This
helps performance but hurts power savings since this
slows down task consolidation by reducing the number
of times load_balance is run.

sched: fine-tune SD_MC_INIT
commit 14800984706bf6936bbec5187f736e928be5c218
Author: Mike Galbraith <efault@gmx.de>
Date: Fri Nov 7 15:26:50 2008 +0100

sched: re-tune balancing -- revert
commit 9fcd18c9e63e325dbd2b4c726623f760788d5aa8
Author: Ingo Molnar <mingo@elte.hu>
Date: Wed Nov 5 16:52:08 2008 +0100

This patch selectively enables SD_BALANCE_NEWIDLE flag
only when sched_mc is set to 1 or 2. This helps power savings
by task consolidation and also does not hurt performance at
sched_mc=0 where all power saving optimisations are turned off.

Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
---
include/linux/sched.h | 10 ++++++++++
include/linux/topology.h | 6 ++++--
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 888f2b2..e894892 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -782,6 +782,16 @@ enum powersavings_balance_level {
((sched_mc_power_savings || sched_smt_power_savings) ? \
SD_POWERSAVINGS_BALANCE : 0)

+/*
+ * Optimise SD flags for power savings:
+ * SD_BALANCE_NEWIDLE helps agressive task consolidation and power savings.
+ * Keep default SD flags if sched_{smt,mc}_power_saving=0
+ */
+
+#define POWERSAVING_SD_FLAGS \
+ ((sched_mc_power_savings || sched_smt_power_savings) ? \
+ SD_BALANCE_NEWIDLE : 0)
+
#define test_sd_parent(sd, flag) ((sd->parent && \
(sd->parent->flags & flag)) ? 1 : 0)

diff --git a/include/linux/topology.h b/include/linux/topology.h
index 117f1b7..26c608c 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -125,7 +125,8 @@ void arch_update_cpu_topology(void);
| SD_WAKE_AFFINE \
| SD_WAKE_BALANCE \
| SD_SHARE_PKG_RESOURCES\
- | BALANCE_FOR_MC_POWER, \
+ | BALANCE_FOR_MC_POWER \
+ | POWERSAVING_SD_FLAGS, \
.last_balance = jiffies, \
.balance_interval = 1, \
}
@@ -150,7 +151,8 @@ void arch_update_cpu_topology(void);
| SD_BALANCE_FORK \
| SD_WAKE_AFFINE \
| SD_WAKE_BALANCE \
- | BALANCE_FOR_PKG_POWER,\
+ | BALANCE_FOR_PKG_POWER \
+ | POWERSAVING_SD_FLAGS, \
.last_balance = jiffies, \
.balance_interval = 1, \
}


\
 
 \ /
  Last update: 2008-12-11 18:45    [from the cache]
©2003-2011 Jasper Spaans