On Thu, Aug 27, 2015 at 10:30:43AM -0700, Guenter Roeck wrote:
> On Thu, Aug 27, 2015 at 04:07:43PM +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_acc entry to measure the processor power
> > consumption and power1_acc just needs to be read twice with an needed
> > interval in-between.
> >
> > A simple example:
> >
> > $ cat /sys/bus/pci/devices/0000\:00\:18.4/hwmon/hwmon0/power1_acc
> > $ sleep 10000s
> > $ cat /sys/bus/pci/devices/0000\:00\:18.4/hwmon/hwmon0/power1_acc
> >
> > The result is current average processor power consumption in 10000
> > seconds. The unit of the result is uWatt.
> >
> > Signed-off-by: Huang Rui <ray.hu...@amd.com>
> > ---
> > drivers/hwmon/fam15h_power.c | 62
> > ++++++++++++++++++++++++++++++++++++++++++++
> > 1 file changed, 62 insertions(+)
> >
> > diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
> > index d529e4b..3bab797 100644
> > --- a/drivers/hwmon/fam15h_power.c
> > +++ b/drivers/hwmon/fam15h_power.c
> > @@ -60,6 +60,7 @@ struct fam15h_power_data {
> > u64 cu_acc_power[MAX_CUS];
> > /* performance timestamp counter */
> > u64 cpu_sw_pwr_ptsc[MAX_CUS];
> > + struct mutex acc_pwr_mutex;
> > };
> >
> > static ssize_t show_power(struct device *dev,
> > @@ -121,17 +122,74 @@ static DEVICE_ATTR(power1_crit, S_IRUGO,
> > show_power_crit, NULL);
> > static struct attribute_group fam15h_power_group;
> > __ATTRIBUTE_GROUPS(fam15h_power);
> >
> > +static ssize_t show_power_acc(struct device *dev,
> > + struct device_attribute *attr, char *buf)
> > +{
> > + int cpu, cu, cu_num, cores_per_cu;
> > + u64 curr_cu_acc_power[MAX_CUS],
> > + curr_ptsc[MAX_CUS], jdelta[MAX_CUS];
> > + u64 tdelta, avg_acc;
> > + struct fam15h_power_data *data = dev_get_drvdata(dev);
> > +
> > + cores_per_cu = amd_get_cores_per_cu();
> > + cu_num = boot_cpu_data.x86_max_cores / cores_per_cu;
> > +
> > + for (cpu = 0, avg_acc = 0; cpu < cu_num * cores_per_cu; cpu +=
> > cores_per_cu) {
> > + cu = cpu / cores_per_cu;
> > + if (rdmsrl_safe_on_cpu(cpu, MSR_F15H_PTSC, &curr_ptsc[cu])) {
> > + pr_err("Failed to read PTSC counter MSR on core%d\n",
> > + cpu);
> > + return 0;
> > + }
> > +
> > + if (rdmsrl_safe_on_cpu(cpu, MSR_F15H_CU_PWR_ACCUMULATOR,
> > + &curr_cu_acc_power[cu])) {
> > + pr_err("Failed to read compute unit power accumulator
> > MSR on core%d\n",
> > + cpu);
> > + return 0;
> > + }
> > +
> > + if (curr_cu_acc_power[cu] < data->cu_acc_power[cu]) {
> > + jdelta[cu] = data->max_cu_acc_power +
> > curr_cu_acc_power[cu];
> > + jdelta[cu] -= data->cu_acc_power[cu];
> > + } else {
> > + jdelta[cu] = curr_cu_acc_power[cu] -
> > data->cu_acc_power[cu];
> > + }
> > + tdelta = curr_ptsc[cu] - data->cpu_sw_pwr_ptsc[cu];
> > + jdelta[cu] *= data->cpu_pwr_sample_ratio * 1000;
> > + do_div(jdelta[cu], tdelta);
> > +
> > + mutex_lock(&data->acc_pwr_mutex);
> > + data->cu_acc_power[cu] = curr_cu_acc_power[cu];
> > + data->cpu_sw_pwr_ptsc[cu] = curr_ptsc[cu];
> > + mutex_unlock(&data->acc_pwr_mutex);
> > +
> > + /* the unit is microWatt */
> > + avg_acc += jdelta[cu];
> > + }
> > +
> > + return sprintf(buf, "%u\n", (unsigned int) avg_acc);
> > +}
> > +static DEVICE_ATTR(power1_acc, S_IRUGO, show_power_acc, NULL);
>
> I am not really a friend of introducing a non-standard attribute.
> Does the energy attribute not work here ?
>
You're right. Non-standard attribute might not be good. Could you
please give me some hints if I use "energy" instead?
Thanks,
Rui
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
