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Commit 11bf0d78 authored by Huang Rui's avatar Huang Rui Committed by Guenter Roeck
Browse files

hwmon: (fam15h_power) Introduce a cpu accumulated power reporting algorithm 



This patch introduces an algorithm that computes the average power by
reading a delta value of “core power accumulator” register during
measurement interval, and then dividing delta value by the length of
the time interval.

User is able to use power1_average entry to measure the processor power
consumption and power1_average_interval entry to set the interval.

A simple example:

ray@hr-ub:~/tip$ sensors
fam15h_power-pci-00c4
Adapter: PCI adapter
power1:       19.58 mW (avg =   2.55 mW, interval =   0.01 s)
                       (crit =  15.00 W)

...

The result is current average processor power consumption in 10
millisecond. The unit of the result is uWatt.

Suggested-by: default avatarGuenter Roeck <linux@roeck-us.net>
Signed-off-by: default avatarHuang Rui <ray.huang@amd.com>
Cc: Borislav Petkov <bp@alien8.de>
Signed-off-by: default avatarGuenter Roeck <linux@roeck-us.net>
parent cdb9e110

drivers/hwmon/fam15h_power.c

+124 −4
Original line number Diff line number Diff line
@@ -27,6 +27,8 @@ 
#include <linux/bitops.h>

#include <linux/cpu.h>

#include <linux/cpumask.h>

#include <linux/time.h>

#include <linux/sched.h>

#include <asm/processor.h>

#include <asm/msr.h>
@@ -48,6 +50,9 @@ MODULE_LICENSE("GPL"); 
#define FAM15H_NUM_GROUPS		2

#define MAX_CUS				8



/* set maximum interval as 1 second */

#define MAX_INTERVAL			1000



#define MSR_F15H_CU_PWR_ACCUMULATOR	0xc001007a

#define MSR_F15H_CU_MAX_PWR_ACCUMULATOR	0xc001007b

#define MSR_F15H_PTSC			0xc0010280
@@ -68,6 +73,9 @@ struct fam15h_power_data { 
	u64 cu_acc_power[MAX_CUS];

	/* performance timestamp counter */

	u64 cpu_sw_pwr_ptsc[MAX_CUS];

	/* online/offline status of current compute unit */

	int cu_on[MAX_CUS];

	unsigned long power_period;

};



static ssize_t show_power(struct device *dev,
@@ -149,6 +157,8 @@ static void do_read_registers_on_cu(void *_data) 


	rdmsrl_safe(MSR_F15H_CU_PWR_ACCUMULATOR, &data->cu_acc_power[cu]);

	rdmsrl_safe(MSR_F15H_PTSC, &data->cpu_sw_pwr_ptsc[cu]);



	data->cu_on[cu] = 1;

}



/*
@@ -165,6 +175,8 @@ static int read_registers(struct fam15h_power_data *data) 
	if (!ret)

		return -ENOMEM;



	memset(data->cu_on, 0, sizeof(int) * MAX_CUS);



	get_online_cpus();

	this_cpu = smp_processor_id();
@@ -199,6 +211,98 @@ static int read_registers(struct fam15h_power_data *data) 
	return 0;

}



static ssize_t acc_show_power(struct device *dev,

			      struct device_attribute *attr,

			      char *buf)

{

	struct fam15h_power_data *data = dev_get_drvdata(dev);

	u64 prev_cu_acc_power[MAX_CUS], prev_ptsc[MAX_CUS],

	    jdelta[MAX_CUS];

	u64 tdelta, avg_acc;

	int cu, cu_num, ret;

	signed long leftover;



	/*

	 * With the new x86 topology modelling, x86_max_cores is the

	 * compute unit number.

	 */

	cu_num = boot_cpu_data.x86_max_cores;



	ret = read_registers(data);

	if (ret)

		return 0;



	for (cu = 0; cu < cu_num; cu++) {

		prev_cu_acc_power[cu] = data->cu_acc_power[cu];

		prev_ptsc[cu] = data->cpu_sw_pwr_ptsc[cu];

	}



	leftover = schedule_timeout_interruptible(msecs_to_jiffies(data->power_period));

	if (leftover)

		return 0;



	ret = read_registers(data);

	if (ret)

		return 0;



	for (cu = 0, avg_acc = 0; cu < cu_num; cu++) {

		/* check if current compute unit is online */

		if (data->cu_on[cu] == 0)

			continue;



		if (data->cu_acc_power[cu] < prev_cu_acc_power[cu]) {

			jdelta[cu] = data->max_cu_acc_power + data->cu_acc_power[cu];

			jdelta[cu] -= prev_cu_acc_power[cu];

		} else {

			jdelta[cu] = data->cu_acc_power[cu] - prev_cu_acc_power[cu];

		}

		tdelta = data->cpu_sw_pwr_ptsc[cu] - prev_ptsc[cu];

		jdelta[cu] *= data->cpu_pwr_sample_ratio * 1000;

		do_div(jdelta[cu], tdelta);



		/* the unit is microWatt */

		avg_acc += jdelta[cu];

	}



	return sprintf(buf, "%llu\n", (unsigned long long)avg_acc);

}

static DEVICE_ATTR(power1_average, S_IRUGO, acc_show_power, NULL);



static ssize_t acc_show_power_period(struct device *dev,

				     struct device_attribute *attr,

				     char *buf)

{

	struct fam15h_power_data *data = dev_get_drvdata(dev);



	return sprintf(buf, "%lu\n", data->power_period);

}



static ssize_t acc_set_power_period(struct device *dev,

				    struct device_attribute *attr,

				    const char *buf, size_t count)

{

	struct fam15h_power_data *data = dev_get_drvdata(dev);

	unsigned long temp;

	int ret;



	ret = kstrtoul(buf, 10, &temp);

	if (ret)

		return ret;



	if (temp > MAX_INTERVAL)

		return -EINVAL;



	/* the interval value should be greater than 0 */

	if (temp <= 0)

		return -EINVAL;



	data->power_period = temp;



	return count;

}

static DEVICE_ATTR(power1_average_interval, S_IRUGO | S_IWUSR,

		   acc_show_power_period, acc_set_power_period);



static int fam15h_power_init_attrs(struct pci_dev *pdev,

				   struct fam15h_power_data *data)

{
@@ -211,6 +315,10 @@ static int fam15h_power_init_attrs(struct pci_dev *pdev, 
	     (c->x86_model >= 0x60 && c->x86_model <= 0x7f)))

		n += 1;



	/* check if processor supports accumulated power */

	if (boot_cpu_has(X86_FEATURE_ACC_POWER))

		n += 2;



	fam15h_power_attrs = devm_kcalloc(&pdev->dev, n,

					  sizeof(*fam15h_power_attrs),

					  GFP_KERNEL);
@@ -225,6 +333,11 @@ static int fam15h_power_init_attrs(struct pci_dev *pdev, 
	     (c->x86_model >= 0x60 && c->x86_model <= 0x7f)))

		fam15h_power_attrs[n++] = &dev_attr_power1_input.attr;



	if (boot_cpu_has(X86_FEATURE_ACC_POWER)) {

		fam15h_power_attrs[n++] = &dev_attr_power1_average.attr;

		fam15h_power_attrs[n++] = &dev_attr_power1_average_interval.attr;

	}



	data->group.attrs = fam15h_power_attrs;



	return 0;
@@ -290,7 +403,7 @@ static int fam15h_power_resume(struct pci_dev *pdev) 
static int fam15h_power_init_data(struct pci_dev *f4,

				  struct fam15h_power_data *data)

{

	u32 val, eax, ebx, ecx, edx;

	u32 val;

	u64 tmp;

	int ret;
@@ -317,10 +430,9 @@ static int fam15h_power_init_data(struct pci_dev *f4, 
	if (ret)

		return ret;



	cpuid(0x80000007, &eax, &ebx, &ecx, &edx);



	/* CPUID Fn8000_0007:EDX[12] indicates to support accumulated power */

	if (!(edx & BIT(12)))

	if (!boot_cpu_has(X86_FEATURE_ACC_POWER))

		return 0;



	/*
@@ -328,7 +440,7 @@ static int fam15h_power_init_data(struct pci_dev *f4, 
	 * sample period to the PTSC counter period by executing CPUID

	 * Fn8000_0007:ECX

	 */

	data->cpu_pwr_sample_ratio = ecx;

	data->cpu_pwr_sample_ratio = cpuid_ecx(0x80000007);



	if (rdmsrl_safe(MSR_F15H_CU_MAX_PWR_ACCUMULATOR, &tmp)) {

		pr_err("Failed to read max compute unit power accumulator MSR\n");
@@ -337,6 +449,14 @@ static int fam15h_power_init_data(struct pci_dev *f4, 


	data->max_cu_acc_power = tmp;



	/*

	 * Milliseconds are a reasonable interval for the measurement.

	 * But it shouldn't set too long here, because several seconds

	 * would cause the read function to hang. So set default

	 * interval as 10 ms.

	 */

	data->power_period = 10;



	return read_registers(data);

}