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arm: topology: Define arch_get_cpu_efficiency() API for scheduler

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On a HMP system, scheduler needs to know efficiency factor
(instructions-per-cycle) for various cpus. This is so that scheduler
can estimate bandwidth consumption of tasks on each cpu, based on
their efficiency factor.

This patch defines arch_get_cpu_efficiency() API in ARM32 architecture.
It depends on hard-coded "efficiency" factor for various cpu types
(available in 'table_efficiency' data structure) and device-tree
providing information on cpu-type for every cpu.

Change-Id: I561bace8a813a35a9fc624fca4861c5b1109b69b
Signed-off-by: Srivatsa Vaddagiri <vatsa@codeaurora.org>
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>
Signed-off-by: Pavankumar Kondeti <pkondeti@codeaurora.org>
This commit is contained in:
Srivatsa Vaddagiri 2014-03-31 19:42:27 -07:00 • committed by Pavankumar Kondeti
parent 46692be6dd
commit 4ac03df1e1
1 changed files with 9 additions and 0 deletions
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9
arch/arm/kernel/topology.c
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@ -190,6 +190,13 @@ static int __init parse_cluster(struct device_node *cluster, int depth)
return 0; return 0;
} }
static DEFINE_PER_CPU(unsigned long, cpu_efficiency) = SCHED_CAPACITY_SCALE;
unsigned long arch_get_cpu_efficiency(int cpu)
{
return per_cpu(cpu_efficiency, cpu);
}
#ifdef CONFIG_OF #ifdef CONFIG_OF
struct cpu_efficiency { struct cpu_efficiency {
const char *compatible; const char *compatible;
@ -281,6 +288,8 @@ static int __init parse_dt_topology(void)
if (cpu_eff->compatible == NULL) if (cpu_eff->compatible == NULL)
continue; continue;
per_cpu(cpu_efficiency, cpu) = cpu_eff->efficiency;
rate = of_get_property(cn, "clock-frequency", &len); rate = of_get_property(cn, "clock-frequency", &len);
if (!rate || len != 4) { if (!rate || len != 4) {
pr_err("%s missing clock-frequency property\n", pr_err("%s missing clock-frequency property\n",