sched: framework for sched_mc/smt_power_savings=N
authorGautham R Shenoy <ego@in.ibm.com>
Thu, 18 Dec 2008 17:56:09 +0000 (22:56 +0530)
committerIngo Molnar <mingo@elte.hu>
Fri, 19 Dec 2008 08:21:46 +0000 (09:21 +0100)
commitafb8a9b70b86866a60e08b2956ae4e1406390336
treee4f8918230f4a4eb696c32edb888bced183001db
parent716707b29906e1d8d190defe3d646610b097a861
sched: framework for sched_mc/smt_power_savings=N

Impact: extend range of /sys/devices/system/cpu/sched_mc_power_savings

Currently the sched_mc/smt_power_savings variable is a boolean,
which either enables or disables topology based power savings.
This patch extends the behaviour of the variable from boolean to
multivalued, such that based on the value, we decide how
aggressively do we want to perform powersavings balance at
appropriate sched domain based on topology.

Variable levels of power saving tunable would benefit end user to
match the required level of power savings vs performance
trade-off depending on the system configuration and workloads.

This version makes the sched_mc_power_savings global variable to
take more values (0,1,2).  Later versions can have a single
tunable called sched_power_savings instead of
sched_{mc,smt}_power_savings.

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
include/linux/sched.h
kernel/sched.c