[RFC PATCH v4 6/7] sched: re-tune balancing -- revert

[Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>]

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

    Reverting this patch since this affects consolidation
    and power savings. Will rework this tuning in the next
    iteration.

    Impact: improve wakeup affinity on NUMA systems, tweak SMP systems

    Given the fixes+tweaks to the wakeup-buddy code, re-tweak the domain
    balancing defaults on NUMA and SMP systems.

    Turn on SD_WAKE_AFFINE which was off on x86 NUMA - there's no reason
    why we would not want to have wakeup affinity across nodes as well.
    (we already do this in the standard NUMA template.)

    lat_ctx on a NUMA box is particularly happy about this change:

    before:

     |   phoenix:~/l> ./lat_ctx -s 0 2
     |   "size=0k ovr=2.60
     |   2 5.70

    after:

     |   phoenix:~/l> ./lat_ctx -s 0 2
     |   "size=0k ovr=2.65
     |   2 2.07

    a 2.75x speedup.

    pipe-test is similarly happy about it too:

     |  phoenix:~/sched-tests> ./pipe-test
     |   18.26 usecs/loop.
     |   14.70 usecs/loop.
     |   14.38 usecs/loop.
     |   10.55 usecs/loop.              # +WAKE_AFFINE on domain0+domain1
     |   8.63 usecs/loop.
     |   8.59 usecs/loop.
     |   9.03 usecs/loop.
     |   8.94 usecs/loop.
     |   8.96 usecs/loop.
     |   8.63 usecs/loop.

    Also:

     - disable SD_BALANCE_NEWIDLE on NUMA and SMP domains (keep it for siblings)
     - enable SD_WAKE_BALANCE on SMP domains

    Sysbench+postgresql improves all around the board, quite significantly:

               .28-rc3-11474e2c  .28-rc3-11474e2c-tune
    -------------------------------------------------
        1:             571              688    +17.08%
        2:            1236             1206    -2.55%
        4:            2381             2642    +9.89%
        8:            4958             5164    +3.99%
       16:            9580             9574    -0.07%
       32:            7128             8118    +12.20%
       64:            7342             8266    +11.18%
      128:            7342             8064    +8.95%
      256:            7519             7884    +4.62%
      512:            7350             7731    +4.93%
    -------------------------------------------------
      SUM:           55412            59341    +6.62%

    So it's a win both for the runup portion, the peak area and the tail.

    Signed-off-by: Ingo Molnar <mingo@elte.hu>
    Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
---

 arch/x86/include/asm/topology.h |    7 +++----
 include/linux/topology.h        |    4 ++--
 2 files changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/x86/include/asm/topology.h b/arch/x86/include/asm/topology.h
index 4850e4b..90ac771 100644
--- a/arch/x86/include/asm/topology.h
+++ b/arch/x86/include/asm/topology.h
@@ -154,7 +154,7 @@ extern unsigned long node_remap_size[];
 
 #endif
 
-/* sched_domains SD_NODE_INIT for NUMA machines */
+/* sched_domains SD_NODE_INIT for NUMAQ machines */
 #define SD_NODE_INIT (struct sched_domain) {		\
 	.min_interval		= 8,			\
 	.max_interval		= 32,			\
@@ -169,9 +169,8 @@ extern unsigned long node_remap_size[];
 	.flags			= SD_LOAD_BALANCE	\
 				| SD_BALANCE_EXEC	\
 				| SD_BALANCE_FORK	\
-				| SD_WAKE_AFFINE	\
-				| SD_WAKE_BALANCE	\
-				| SD_SERIALIZE,		\
+				| SD_SERIALIZE		\
+				| SD_WAKE_BALANCE,	\
 	.last_balance		= jiffies,		\
 	.balance_interval	= 1,			\
 }
diff --git a/include/linux/topology.h b/include/linux/topology.h
index 117f1b7..2565f4a 100644
--- a/include/linux/topology.h
+++ b/include/linux/topology.h
@@ -146,10 +146,10 @@ void arch_update_cpu_topology(void);
 	.wake_idx		= 1,			\
 	.forkexec_idx		= 1,			\
 	.flags			= SD_LOAD_BALANCE	\
-				| SD_BALANCE_EXEC	\
+				| SD_BALANCE_NEWIDLE	\
 				| SD_BALANCE_FORK	\
+				| SD_BALANCE_EXEC	\
 				| SD_WAKE_AFFINE	\
-				| SD_WAKE_BALANCE	\
 				| BALANCE_FOR_PKG_POWER,\
 	.last_balance		= jiffies,		\
 	.balance_interval	= 1,			\