Commit 5c45bf27 authored by Siddha, Suresh B's avatar Siddha, Suresh B Committed by Linus Torvalds
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[PATCH] sched: mc/smt power savings sched policy 



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: default avatarSuresh 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: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 36938169

arch/i386/kernel/smpboot.c

+5 −3
Original line number Diff line number Diff line
@@ -448,9 +448,11 @@ cpumask_t cpu_coregroup_map(int cpu) 
	struct cpuinfo_x86 *c = cpu_data + cpu;

	/*

	 * For perf, we return last level cache shared map.

	 * TBD: when power saving sched policy is added, we will return

	 *      cpu_core_map when power saving policy is enabled

	 * And for power savings, we return cpu_core_map

	 */

	if (sched_mc_power_savings || sched_smt_power_savings)

		return cpu_core_map[cpu];

	else

		return c->llc_shared_map;

}

arch/x86_64/kernel/smpboot.c

+5 −3
Original line number Diff line number Diff line
@@ -455,9 +455,11 @@ cpumask_t cpu_coregroup_map(int cpu) 
	struct cpuinfo_x86 *c = cpu_data + cpu;

	/*

	 * For perf, we return last level cache shared map.

	 * TBD: when power saving sched policy is added, we will return

	 *      cpu_core_map when power saving policy is enabled

	 * And for power savings, we return cpu_core_map

	 */

	if (sched_mc_power_savings || sched_smt_power_savings)

		return cpu_core_map[cpu];

	else

		return c->llc_shared_map;

}

drivers/base/cpu.c

+9 −1
Original line number Diff line number Diff line
@@ -143,5 +143,13 @@ EXPORT_SYMBOL_GPL(get_cpu_sysdev); 


int __init cpu_dev_init(void)

{

	return sysdev_class_register(&cpu_sysdev_class);

	int err;



	err = sysdev_class_register(&cpu_sysdev_class);

#if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT)

	if (!err)

		err = sched_create_sysfs_power_savings_entries(&cpu_sysdev_class);

#endif



	return err;

}

include/asm-i386/topology.h

+5 −0
Original line number Diff line number Diff line
@@ -112,4 +112,9 @@ extern unsigned long node_remap_size[]; 


extern cpumask_t cpu_coregroup_map(int cpu);



#ifdef CONFIG_SMP

#define mc_capable()	(boot_cpu_data.x86_max_cores > 1)

#define smt_capable()	(smp_num_siblings > 1)

#endif



#endif /* _ASM_I386_TOPOLOGY_H */

include/asm-ia64/topology.h

+1 −0
Original line number Diff line number Diff line
@@ -112,6 +112,7 @@ void build_cpu_to_node_map(void); 
#define topology_core_id(cpu)			(cpu_data(cpu)->core_id)

#define topology_core_siblings(cpu)		(cpu_core_map[cpu])

#define topology_thread_siblings(cpu)		(cpu_sibling_map[cpu])

#define smt_capable() 				(smp_num_siblings > 1)

#endif



#include <asm-generic/topology.h>

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