![Siddha, Suresh B](/assets/img/avatar_default.png)
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>
121 lines
3.3 KiB
C
121 lines
3.3 KiB
C
/*
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* linux/include/asm-i386/topology.h
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*
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* Written by: Matthew Dobson, IBM Corporation
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*
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* Copyright (C) 2002, IBM Corp.
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for more
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* details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* Send feedback to <colpatch@us.ibm.com>
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*/
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#ifndef _ASM_I386_TOPOLOGY_H
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#define _ASM_I386_TOPOLOGY_H
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#ifdef CONFIG_X86_HT
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#define topology_physical_package_id(cpu) (cpu_data[cpu].phys_proc_id)
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#define topology_core_id(cpu) (cpu_data[cpu].cpu_core_id)
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#define topology_core_siblings(cpu) (cpu_core_map[cpu])
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#define topology_thread_siblings(cpu) (cpu_sibling_map[cpu])
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#endif
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#ifdef CONFIG_NUMA
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#include <asm/mpspec.h>
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#include <linux/cpumask.h>
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/* Mappings between logical cpu number and node number */
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extern cpumask_t node_2_cpu_mask[];
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extern int cpu_2_node[];
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/* Returns the number of the node containing CPU 'cpu' */
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static inline int cpu_to_node(int cpu)
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{
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return cpu_2_node[cpu];
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}
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/* Returns the number of the node containing Node 'node'. This architecture is flat,
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so it is a pretty simple function! */
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#define parent_node(node) (node)
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/* Returns a bitmask of CPUs on Node 'node'. */
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static inline cpumask_t node_to_cpumask(int node)
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{
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return node_2_cpu_mask[node];
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}
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/* Returns the number of the first CPU on Node 'node'. */
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static inline int node_to_first_cpu(int node)
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{
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cpumask_t mask = node_to_cpumask(node);
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return first_cpu(mask);
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}
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#define pcibus_to_node(bus) ((long) (bus)->sysdata)
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#define pcibus_to_cpumask(bus) node_to_cpumask(pcibus_to_node(bus))
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/* sched_domains SD_NODE_INIT for NUMAQ machines */
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#define SD_NODE_INIT (struct sched_domain) { \
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.span = CPU_MASK_NONE, \
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.parent = NULL, \
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.groups = NULL, \
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.min_interval = 8, \
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.max_interval = 32, \
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.busy_factor = 32, \
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.imbalance_pct = 125, \
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.cache_nice_tries = 1, \
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.busy_idx = 3, \
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.idle_idx = 1, \
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.newidle_idx = 2, \
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.wake_idx = 1, \
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.per_cpu_gain = 100, \
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.flags = SD_LOAD_BALANCE \
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| SD_BALANCE_EXEC \
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| SD_BALANCE_FORK \
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| SD_WAKE_BALANCE, \
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.last_balance = jiffies, \
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.balance_interval = 1, \
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.nr_balance_failed = 0, \
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}
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extern unsigned long node_start_pfn[];
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extern unsigned long node_end_pfn[];
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extern unsigned long node_remap_size[];
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#define node_has_online_mem(nid) (node_start_pfn[nid] != node_end_pfn[nid])
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#else /* !CONFIG_NUMA */
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/*
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* Other i386 platforms should define their own version of the
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* above macros here.
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*/
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#include <asm-generic/topology.h>
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#endif /* CONFIG_NUMA */
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extern cpumask_t cpu_coregroup_map(int cpu);
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#ifdef CONFIG_SMP
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#define mc_capable() (boot_cpu_data.x86_max_cores > 1)
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#define smt_capable() (smp_num_siblings > 1)
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#endif
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#endif /* _ASM_I386_TOPOLOGY_H */
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