From: Dietmar Eggemann <dietmar.eggemann@arm.com>
To: Juri Lelli <juri.lelli@arm.com>, linux-kernel@vger.kernel.org
Cc: linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
devicetree@vger.kernel.org, peterz@infradead.org,
vincent.guittot@linaro.org, robh+dt@kernel.org,
mark.rutland@arm.com, linux@arm.linux.org.uk,
sudeep.holla@arm.com, lorenzo.pieralisi@arm.com,
catalin.marinas@arm.com, will.deacon@arm.com,
morten.rasmussen@arm.com, Mark Brown <broonie@linaro.org>
Subject: Re: [RFC PATCH 5/8] arm64: parse cpu capacity from DT
Date: Thu, 10 Dec 2015 14:15:00 +0000 [thread overview]
Message-ID: <566988E4.1000003@arm.com> (raw)
In-Reply-To: <1448288921-30307-6-git-send-email-juri.lelli@arm.com>
On 23/11/15 14:28, Juri Lelli wrote:
> With the introduction of cpu capacity bindings, CPU capacities can now be
> extracted from DT. Add parsing of such information at boot time. Also,
> store such information using per CPU variables, as we do for arm.
>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Will Deacon <will.deacon@arm.com>
> Cc: Mark Brown <broonie@linaro.org>
> Cc: Sudeep Holla <sudeep.holla@arm.com>
> Signed-off-by: Juri Lelli <juri.lelli@arm.com>
> ---
> arch/arm64/kernel/topology.c | 46 ++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 46 insertions(+)
A lot of code disappears if you get rid of capacity-scale.
>
> diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
> index 694f6de..4423cc5 100644
> --- a/arch/arm64/kernel/topology.c
> +++ b/arch/arm64/kernel/topology.c
> @@ -23,6 +23,45 @@
> #include <asm/cputype.h>
> #include <asm/topology.h>
>
> +static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE;
> +
> +unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu)
> +{
> + return per_cpu(cpu_scale, cpu);
> +}
> +
> +static void set_capacity_scale(unsigned int cpu, unsigned long capacity)
> +{
> + per_cpu(cpu_scale, cpu) = capacity;
> +}
> +
> +static u32 capacity_scale = SCHED_CAPACITY_SCALE;
> +
> +static void __init parse_cpu_capacity(struct device_node *cpu_node, int cpu)
> +{
> + int ret;
> + u32 cpu_capacity;
> +
> + ret = of_property_read_u32(cpu_node,
> + "capacity",
> + &cpu_capacity);
> + if (!ret) {
> + u64 capacity;
> +
> + /*
> + * Enforce capacity <= capacity-scale.
> + */
> + cpu_capacity = cpu_capacity <= capacity_scale ? cpu_capacity :
> + capacity_scale;
> + capacity = (cpu_capacity << SCHED_CAPACITY_SHIFT) /
> + capacity_scale;
> +
> + set_capacity_scale(cpu, capacity);
> + pr_info("CPU%d: DT cpu_capacity %lu\n",
> + cpu, arch_scale_cpu_capacity(NULL, cpu));
> + }
> +}
> +
> static int __init get_cpu_for_node(struct device_node *node)
> {
> struct device_node *cpu_node;
> @@ -34,6 +73,7 @@ static int __init get_cpu_for_node(struct device_node *node)
>
> for_each_possible_cpu(cpu) {
> if (of_get_cpu_node(cpu, NULL) == cpu_node) {
> + parse_cpu_capacity(cpu_node, cpu);
> of_node_put(cpu_node);
> return cpu;
> }
> @@ -173,6 +213,12 @@ static int __init parse_dt_topology(void)
> return 0;
> }
>
> + if (!of_property_read_u32(cn, "capacity-scale", &capacity_scale))
> + pr_info("DT cpus capacity-scale %u\n", capacity_scale);
> + else
> + pr_debug("DT cpus capacity-scale not found: assuming %u\n",
> + capacity_scale);
> +
> /*
> * When topology is provided cpu-map is essentially a root
> * cluster with restricted subnodes.
>
next prev parent reply other threads:[~2015-12-10 14:15 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-23 14:28 [RFC PATCH 0/8] CPUs capacity information for heterogeneous systems Juri Lelli
2015-11-23 14:28 ` [RFC PATCH 1/8] ARM: initialize cpu_scale to its default Juri Lelli
2015-11-30 11:13 ` Vincent Guittot
2015-11-23 14:28 ` [RFC PATCH 2/8] Documentation: arm: define DT cpu capacity bindings Juri Lelli
2015-11-24 2:06 ` Rob Herring
2015-11-24 10:54 ` Juri Lelli
2015-11-30 9:59 ` Vincent Guittot
2015-12-01 11:20 ` Juri Lelli
2015-12-10 14:14 ` Dietmar Eggemann
2015-12-11 10:09 ` Juri Lelli
2015-12-10 15:30 ` Mark Brown
2015-12-10 17:58 ` Juri Lelli
2015-12-11 17:49 ` Mark Brown
[not found] ` <20151211174940.GQ5727-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2015-12-14 12:36 ` Juri Lelli
2015-12-14 16:59 ` Mark Brown
2015-12-15 12:22 ` Juri Lelli
2015-12-15 13:39 ` Mark Brown
2015-12-15 14:01 ` Mark Rutland
2015-12-15 14:24 ` Juri Lelli
2015-12-15 14:50 ` Mark Rutland
2015-12-15 15:36 ` Juri Lelli
2015-12-15 15:08 ` Mark Brown
[not found] ` <20151215150813.GZ5727-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2015-12-15 15:32 ` Mark Rutland
2015-12-15 15:46 ` Juri Lelli
2015-12-15 15:57 ` Mark Rutland
2015-12-15 16:23 ` Catalin Marinas
2015-12-15 16:41 ` Mark Rutland
2015-12-15 16:59 ` Vincent Guittot
[not found] ` <CAKfTPtAuosPcL8bbQ27Y-vUE1h4QRY8hGESnm4YrxqRAQ3K=5g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-12-15 17:15 ` Mark Rutland
2015-12-15 17:47 ` Vincent Guittot
[not found] ` <CAKfTPtBzWcNHx+Fi7hUabNpPsd1thFAkPnLcpsnqbQp6Qq24cQ-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2015-12-15 18:39 ` Mark Rutland
2015-12-15 17:17 ` Mark Brown
[not found] ` <20151215171713.GA5727-GFdadSzt00ze9xe1eoZjHA@public.gmane.org>
2015-12-15 17:28 ` Mark Rutland
2015-12-15 17:45 ` Mark Brown
2015-12-15 18:10 ` Mark Rutland
2015-12-15 18:45 ` Mark Brown
2015-12-17 9:07 ` Juri Lelli
2015-12-15 13:55 ` Vincent Guittot
2015-11-23 14:28 ` [RFC PATCH 3/8] arm: parse cpu capacity from DT Juri Lelli
2015-12-10 14:14 ` Dietmar Eggemann
[not found] ` <566988DD.9080005-5wv7dgnIgG8@public.gmane.org>
2015-12-11 10:12 ` Juri Lelli
2015-11-23 14:28 ` [RFC PATCH 4/8] arm, dts: add TC2 cpu capacity information Juri Lelli
2015-11-23 14:28 ` [RFC PATCH 5/8] arm64: parse cpu capacity from DT Juri Lelli
2015-12-10 14:15 ` Dietmar Eggemann [this message]
2015-12-11 10:07 ` Juri Lelli
2015-11-23 14:28 ` [RFC PATCH 6/8] arm64, dts: add Juno cpu capacity information Juri Lelli
2015-11-23 14:28 ` [RFC PATCH 7/8] arm: add sysfs cpu_capacity attribute Juri Lelli
2015-11-23 14:28 ` [RFC PATCH 8/8] arm64: " Juri Lelli
2015-12-10 14:15 ` Dietmar Eggemann
2015-12-10 15:59 ` Mark Brown
2015-12-10 18:01 ` Juri Lelli
2015-12-11 17:54 ` Mark Brown
2015-12-07 12:02 ` [RFC PATCH 0/8] CPUs capacity information for heterogeneous systems Juri Lelli
2015-12-07 12:11 ` Russell King - ARM Linux
2015-12-07 12:36 ` Juri Lelli
2015-12-07 13:18 ` Russell King - ARM Linux
[not found] ` <20151207131843.GP8644-l+eeeJia6m9vn6HldHNs0ANdhmdF6hFW@public.gmane.org>
2015-12-07 15:41 ` Juri Lelli
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