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Message-ID: <20160328093327.GC26651@pd.tnic>
Date: Mon, 28 Mar 2016 11:33:27 +0200
From: Borislav Petkov <bp@...en8.de>
To: Huang Rui <ray.huang@....com>
Cc: Guenter Roeck <linux@...ck-us.net>,
Jean Delvare <jdelvare@...e.de>, linux-hwmon@...r.kernel.org,
linux-kernel@...r.kernel.org, spg_linux_kernel@....com
Subject: Re: [PATCH v5 4/6] hwmon: (fam15h_power) Introduce a cpu accumulated
power reporting algorithm
On Mon, Mar 28, 2016 at 01:32:14PM +0800, Huang Rui wrote:
> 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@...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: Guenter Roeck <linux@...ck-us.net>
> Signed-off-by: Huang Rui <ray.huang@....com>
> Cc: Borislav Petkov <bp@...en8.de>
> ---
> drivers/hwmon/fam15h_power.c | 119 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 119 insertions(+)
>
> diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
> index de6f52b..003564b 100644
> --- a/drivers/hwmon/fam15h_power.c
> +++ b/drivers/hwmon/fam15h_power.c
> @@ -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 = get_cpu();
>
> @@ -192,18 +204,117 @@ 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)
> {
> int n = FAM15H_MIN_NUM_ATTRS;
> struct attribute **fam15h_power_attrs;
> struct cpuinfo_x86 *c = &boot_cpu_data;
> + u32 cpuid;
>
> if (c->x86 == 0x15 &&
> (c->x86_model <= 0xf ||
> (c->x86_model >= 0x60 && c->x86_model <= 0x7f)))
> n += 1;
>
> + cpuid = cpuid_edx(0x80000007);
> +
> + /* check if processor supports accumulated power */
> + if (cpuid & BIT(12))
> + n += 2;
if (boot_cpu_has(X86_FEATURE_ACC_POWER))
> +
> fam15h_power_attrs = devm_kcalloc(&pdev->dev, n,
> sizeof(*fam15h_power_attrs),
> GFP_KERNEL);
> @@ -218,6 +329,11 @@ 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 (cpuid & BIT(12)) {
Ditto.
> + 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;
> @@ -330,6 +446,9 @@ static int fam15h_power_init_data(struct pci_dev *f4,
>
> data->max_cu_acc_power = tmp;
>
> + /* set default interval as 10 ms */
Because...?
> + data->power_period = 10;
> +
> return read_registers(data);
> }
>
> --
> 1.9.1
>
>
--
Regards/Gruss,
Boris.
ECO tip #101: Trim your mails when you reply.
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