Commit fd5704aa authored Mar 31, 2014 by Srivatsa Vaddagiri Committed by Pavankumar Kondeti Jun 01, 2017

arm: topology: Define arch_get_cpu_efficiency() API for scheduler



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>

parent 1fd6e206

arch/arm/kernel/topology.c

+9 −0

Original line number	Diff line number	Diff line
		@@ -196,6 +196,13 @@ static int __init parse_cluster(struct device_node *cluster, int depth)
		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
		struct cpu_efficiency {
		const char *compatible;
		@@ -287,6 +294,8 @@ static int __init parse_dt_topology(void)
		if (cpu_eff->compatible == NULL)
		continue;

		per_cpu(cpu_efficiency, cpu) = cpu_eff->efficiency;

		rate = of_get_property(cn, "clock-frequency", &len);
		if (!rate \|\| len != 4) {
		pr_err("%s missing clock-frequency property\n",