From: Juri Lelli <juri.lelli@arm.com>
To: 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, dietmar.eggemann@arm.com,
juri.lelli@arm.com, broonie@kernel.org
Subject: [PATCH v3 5/6] arm: add sysfs cpu_capacity attribute
Date: Wed, 3 Feb 2016 11:59:58 +0000 [thread overview]
Message-ID: <1454500799-18451-6-git-send-email-juri.lelli@arm.com> (raw)
In-Reply-To: <1454500799-18451-1-git-send-email-juri.lelli@arm.com>
Add a sysfs cpu_capacity attribute with which it is possible to read and
write (thus over-writing default values) CPUs capacity. This might be
useful in situation where there is no way to get proper default values
at boot time.
The new attribute shows up as:
/sys/devices/system/cpu/cpu*/cpu_capacity
Cc: Russell King <linux@arm.linux.org.uk>
Signed-off-by: Juri Lelli <juri.lelli@arm.com>
---
arch/arm/kernel/topology.c | 68 ++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 68 insertions(+)
diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c
index 7d7fc2c..9ffba65 100644
--- a/arch/arm/kernel/topology.c
+++ b/arch/arm/kernel/topology.c
@@ -57,6 +57,74 @@ bool arch_wants_init_cpu_capacity(void)
return true;
}
+#ifdef CONFIG_PROC_SYSCTL
+#include <asm/cpu.h>
+#include <linux/string.h>
+static ssize_t show_cpu_capacity(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct cpu *cpu = container_of(dev, struct cpu, dev);
+ ssize_t rc;
+ int cpunum = cpu->dev.id;
+ unsigned long capacity = arch_scale_cpu_capacity(NULL, cpunum);
+
+ rc = sprintf(buf, "%lu\n", capacity);
+
+ return rc;
+}
+
+static ssize_t store_cpu_capacity(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf,
+ size_t count)
+{
+ struct cpu *cpu = container_of(dev, struct cpu, dev);
+ int this_cpu = cpu->dev.id, i;
+ unsigned long new_capacity;
+ ssize_t ret;
+
+ if (count) {
+ char *p = (char *) buf;
+
+ ret = kstrtoul(p, 0, &new_capacity);
+ if (ret)
+ return ret;
+ if (new_capacity > SCHED_CAPACITY_SCALE)
+ return -EINVAL;
+
+ for_each_cpu(i, &cpu_topology[this_cpu].core_sibling)
+ set_capacity_scale(i, new_capacity);
+ }
+
+ return count;
+}
+
+static DEVICE_ATTR(cpu_capacity,
+ 0644,
+ show_cpu_capacity,
+ store_cpu_capacity);
+
+static int register_cpu_capacity_sysctl(void)
+{
+ int i;
+ struct device *cpu;
+
+ for_each_possible_cpu(i) {
+ cpu = get_cpu_device(i);
+ if (!cpu) {
+ pr_err("%s: too early to get CPU%d device!\n",
+ __func__, i);
+ continue;
+ }
+ device_create_file(cpu, &dev_attr_cpu_capacity);
+ }
+
+ return 0;
+}
+late_initcall(register_cpu_capacity_sysctl);
+#endif
+
#ifdef CONFIG_OF
struct cpu_efficiency {
const char *compatible;
--
2.7.0
next prev parent reply other threads:[~2016-02-03 12:00 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-03 11:59 [PATCH v3 0/6] CPUs capacity information for heterogeneous systems Juri Lelli
2016-02-03 11:59 ` [PATCH v3 1/6] ARM: initialize cpu_scale to its default Juri Lelli
2016-02-03 11:59 ` [PATCH v3 2/6] drivers/cpufreq: implement init_cpu_capacity_default() Juri Lelli
2016-02-03 21:04 ` Vincent Guittot
2016-02-04 9:36 ` Morten Rasmussen
2016-02-04 12:03 ` Vincent Guittot
2016-02-04 12:16 ` Juri Lelli
2016-02-04 12:35 ` Vincent Guittot
2016-02-04 14:13 ` Juri Lelli
2016-02-04 15:44 ` Vincent Guittot
2016-02-04 15:46 ` Vincent Guittot
2016-02-05 9:30 ` Juri Lelli
2016-02-09 15:54 ` Dietmar Eggemann
2016-02-10 14:25 ` Juri Lelli
2016-02-03 11:59 ` [PATCH v3 3/6] arm: Enable dynamic CPU capacity initialization Juri Lelli
2016-02-03 11:59 ` [PATCH v3 4/6] arm64: " Juri Lelli
2016-02-08 12:28 ` Dietmar Eggemann
2016-02-08 13:13 ` Mark Brown
2016-02-08 13:41 ` Dietmar Eggemann
2016-02-03 11:59 ` Juri Lelli [this message]
2016-02-03 11:59 ` [PATCH v3 6/6] arm64: add sysfs cpu_capacity attribute Juri Lelli
2016-02-05 17:19 ` Dietmar Eggemann
2016-02-05 17:49 ` Juri Lelli
2016-02-08 23:59 ` [PATCH v3 0/6] CPUs capacity information for heterogeneous systems Steve Muckle
2016-02-09 10:37 ` Juri Lelli
2016-02-09 17:30 ` Steve Muckle
2016-02-09 17:40 ` Juri Lelli
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