[PATCH v6 2/6] hwmon: (fam15h_power) Add compute unit accumulated power

Huang Rui
2016-04-06T07:59:55Z

This patch adds a member in fam15h_power_data which specifies the
compute unit accumulated power. It adds do_read_registers_on_cu to do
all the read to all MSRs and run it on one of the online cores on each
compute unit with smp_call_function_many(). This behavior can decrease
IPI numbers.

Suggested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Huang Rui <ray.huang@amd.com>
---
drivers/hwmon/fam15h_power.c | 72 +++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 71 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
index 4f695d8..4edbaf0 100644
--- a/drivers/hwmon/fam15h_power.c
+++ b/drivers/hwmon/fam15h_power.c
@@ -25,6 +25,8 @@
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/bitops.h>
+#include <linux/cpu.h>
+#include <linux/cpumask.h>
#include <asm/processor.h>
#include <asm/msr.h>

@@ -44,7 +46,9 @@ MODULE_LICENSE("GPL");

#define FAM15H_MIN_NUM_ATTRS 2
#define FAM15H_NUM_GROUPS 2
+#define MAX_CUS 8

+#define MSR_F15H_CU_PWR_ACCUMULATOR 0xc001007a
#define MSR_F15H_CU_MAX_PWR_ACCUMULATOR 0xc001007b

#define PCI_DEVICE_ID_AMD_15H_M70H_NB_F4 0x15b4
@@ -59,6 +63,8 @@ struct fam15h_power_data {
struct attribute_group group;
/* maximum accumulated power of a compute unit */
u64 max_cu_acc_power;
+ /* accumulated power of the compute units */
+ u64 cu_acc_power[MAX_CUS];
};

static ssize_t show_power(struct device *dev,
@@ -125,6 +131,70 @@ static ssize_t show_power_crit(struct device *dev,
}
static DEVICE_ATTR(power1_crit, S_IRUGO, show_power_crit, NULL);

+static void do_read_registers_on_cu(void *_data)
+{
+ struct fam15h_power_data *data = _data;
+ int cpu, cu;
+
+ cpu = smp_processor_id();
+
+ /*
+ * With the new x86 topology modelling, cpu core id actually
+ * is compute unit id.
+ */
+ cu = cpu_data(cpu).cpu_core_id;
+
+ rdmsrl_safe(MSR_F15H_CU_PWR_ACCUMULATOR, &data->cu_acc_power[cu]);
+}
+
+/*
+ * This function is only able to be called when CPUID
+ * Fn8000_0007:EDX[12] is set.
+ */
+static int read_registers(struct fam15h_power_data *data)
+{
+ int this_cpu, ret, cpu;
+ int core, this_core;
+ cpumask_var_t mask;
+
+ ret = zalloc_cpumask_var(&mask, GFP_KERNEL);
+ if (!ret)
+ return -ENOMEM;
+
+ get_online_cpus();
+ this_cpu = smp_processor_id();
+
+ /*
+ * Choose the first online core of each compute unit, and then
+ * read their MSR value of power and ptsc in a single IPI,
+ * because the MSR value of CPU core represent the compute
+ * unit's.
+ */
+ core = -1;
+
+ for_each_online_cpu(cpu) {
+ this_core = topology_core_id(cpu);
+
+ if (this_core == core)
+ continue;
+
+ core = this_core;
+
+ /* get any CPU on this compute unit */
+ cpumask_set_cpu(cpumask_any(topology_sibling_cpumask(cpu)), mask);
+ }
+
+ if (cpumask_test_cpu(this_cpu, mask))
+ do_read_registers_on_cu(data);
+
+ smp_call_function_many(mask, do_read_registers_on_cu, data, true);
+ put_online_cpus();
+
+ free_cpumask_var(mask);
+
+ return 0;
+}
+
static int fam15h_power_init_attrs(struct pci_dev *pdev,
struct fam15h_power_data *data)
{
@@ -263,7 +333,7 @@ static int fam15h_power_init_data(struct pci_dev *f4,

data->max_cu_acc_power = tmp;

- return 0;
+ return read_registers(data);
}

static int fam15h_power_probe(struct pci_dev *pdev,
--
1.9.1