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, sgurrappadi@nvidia.com,
Mark Brown <broonie@linaro.org>
Subject: [PATCH v5 8/8] arm64: add sysfs cpu_capacity attribute
Date: Wed, 15 Jun 2016 11:17:57 +0100 [thread overview]
Message-ID: <1465985877-18271-9-git-send-email-juri.lelli@arm.com> (raw)
In-Reply-To: <1465985877-18271-1-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 situations where values needs changing after boot.
The new attribute shows up as:
/sys/devices/system/cpu/cpu*/cpu_capacity
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 | 68 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 68 insertions(+)
diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index 780c2c7..33a35411 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c
@@ -37,6 +37,74 @@ static void set_capacity_scale(unsigned int cpu, unsigned long capacity)
per_cpu(cpu_scale, cpu) = capacity;
}
+#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
+
static u32 capacity_scale;
static u32 *raw_capacity;
static bool cap_parsing_failed;
--
2.7.0
prev parent reply other threads:[~2016-06-15 10:19 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-15 10:17 [PATCH v5 0/8] CPUs capacity information for heterogeneous systems Juri Lelli
2016-06-15 10:17 ` [PATCH v5 1/8] Documentation: arm: define DT cpu capacity-dmips-mhz bindings Juri Lelli
2016-06-15 12:51 ` Vincent Guittot
2016-06-15 14:24 ` Juri Lelli
2016-06-15 14:04 ` Mark Brown
2016-06-15 14:22 ` Juri Lelli
2016-06-15 22:11 ` Rob Herring
2016-06-16 8:20 ` Juri Lelli
2016-06-22 16:51 ` Juri Lelli
2016-06-15 10:17 ` [PATCH v5 2/8] arm: parse cpu capacity-dmips-mhz from DT Juri Lelli
2016-06-15 10:17 ` [PATCH v5 3/8] arm, dts: add TC2 cpu capacity-dmips-mhz information Juri Lelli
2016-06-15 10:17 ` [PATCH v5 4/8] arm64: parse cpu capacity-dmips-mhz from DT Juri Lelli
[not found] ` <CADRr18P=EOwpZTc-aS=4cCa8B3ObpuqpbNNv+w5Q4shXD6s7HQ@mail.gmail.com>
2016-06-15 10:25 ` Juri Lelli
2016-06-15 13:49 ` Mark Brown
2016-06-15 14:48 ` Juri Lelli
2016-06-15 10:17 ` [PATCH v5 5/8] arm64, dts: add Juno cpu capacity-dmips-mhz information Juri Lelli
2016-06-15 10:17 ` [PATCH v5 6/8] arm64, dts: add Juno r2 " Juri Lelli
2016-06-15 10:17 ` [PATCH v5 7/8] arm: add sysfs cpu_capacity attribute Juri Lelli
2016-06-15 10:17 ` Juri Lelli [this message]
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