From 5c45bf279d378d436ce45825c0f136696c7b6109 Mon Sep 17 00:00:00 2001 From: "Siddha, Suresh B" Date: Tue, 27 Jun 2006 02:54:42 -0700 Subject: [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: Suresh Siddha Cc: Ingo Molnar Cc: Nick Piggin Cc: Con Kolivas Cc: "Chen, Kenneth W" Cc: "David S. Miller" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86_64/kernel/smpboot.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'arch/x86_64') diff --git a/arch/x86_64/kernel/smpboot.c b/arch/x86_64/kernel/smpboot.c index 4e97551..540c0cc 100644 --- a/arch/x86_64/kernel/smpboot.c +++ b/arch/x86_64/kernel/smpboot.c @@ -455,10 +455,12 @@ 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 */ - return c->llc_shared_map; + if (sched_mc_power_savings || sched_smt_power_savings) + return cpu_core_map[cpu]; + else + return c->llc_shared_map; } /* representing cpus for which sibling maps can be computed */ -- cgit v1.1