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[PATCH] sched: mc/smt power savings sched policy

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sysfs entries 'sched_mc_power_savings' and 'sched_smt_power_savings' in
/sys/devices/system/cpu/ control the MC/SMT power savings policy for the
scheduler.

Based on the values (1-enable, 0-disable) for these controls, sched groups
cpu power will be determined for different domains.  When power savings
policy is enabled and under light load conditions, scheduler will minimize
the physical packages/cpu cores carrying the load and thus conserving
power(with a perf impact based on the workload characteristics...  see OLS
2005 CMP kernel scheduler paper for more details..)

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Con Kolivas <kernel@kolivas.org>
Cc: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Siddha, Suresh B
2006-06-27 02:54:42 -07:00
committed by Linus Torvalds
parent 369381694d
commit 5c45bf279d
11 changed files with 264 additions and 35 deletions
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10
include/linux/sched.h
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@@ -570,6 +570,11 @@ enum idle_type
#define SD_WAKE_AFFINE 32 /* Wake task to waking CPU */
#define SD_WAKE_BALANCE 64 /* Perform balancing at task wakeup */
#define SD_SHARE_CPUPOWER 128 /* Domain members share cpu power */
#define SD_POWERSAVINGS_BALANCE 256 /* Balance for power savings */
#define BALANCE_FOR_POWER ((sched_mc_power_savings || sched_smt_power_savings) \
? SD_POWERSAVINGS_BALANCE : 0)
struct sched_group {
struct sched_group *next; /* Must be a circular list */
@@ -1412,6 +1417,11 @@ static inline void arch_pick_mmap_layout(struct mm_struct *mm)
extern long sched_setaffinity(pid_t pid, cpumask_t new_mask);
extern long sched_getaffinity(pid_t pid, cpumask_t *mask);
#include <linux/sysdev.h>
extern int sched_mc_power_savings, sched_smt_power_savings;
extern struct sysdev_attribute attr_sched_mc_power_savings, attr_sched_smt_power_savings;
extern int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls);
extern void normalize_rt_tasks(void);
#ifdef CONFIG_PM