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SubjectRe: [PATCH v2 07/10] hwmon: (fam15h_power) Introduce a cpu accumulated power reporting algorithm
On Tue, Oct 20, 2015 at 10:28:26AM +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@hr-ub:~/tip$ sensors
> fam15h_power-pci-00c4
> Adapter: PCI adapter
> power1: 23.73 mW (avg = 634.63 mW, interval = 0.01 s)
> (crit = 15.00 W)
>
> ...

I need to play with this more after I get back from KS. Just a partial
review for now.

>
> The result is current average processor power consumption in 10
> millisecond. The unit of the result is uWatt.
>
> Suggested-by: Guenter Roeck <linux@roeck-us.net>
> Signed-off-by: Huang Rui <ray.huang@amd.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@kernel.org>
> ---
> drivers/hwmon/fam15h_power.c | 120 +++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 120 insertions(+)
>
> diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
> index 6321f73..a5a539e 100644
> --- a/drivers/hwmon/fam15h_power.c
> +++ b/drivers/hwmon/fam15h_power.c
> @@ -26,6 +26,9 @@
> #include <linux/pci.h>
> #include <linux/bitops.h>
> #include <linux/cpumask.h>
> +#include <linux/mutex.h>
> +#include <linux/time.h>
> +#include <linux/sched.h>
> #include <asm/processor.h>
> #include <asm/msr.h>
>
> @@ -64,6 +67,10 @@ 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;
> + struct mutex acc_pwr_mutex;
> };
>
> static ssize_t show_power(struct device *dev,
> @@ -132,11 +139,15 @@ static void do_read_registers_on_cu(void *_data)
> cores_per_cu = amd_get_cores_per_cu();
> cu = cpu / cores_per_cu;
>
> + mutex_lock(&data->acc_pwr_mutex);
> WARN_ON(rdmsrl_safe(MSR_F15H_CU_PWR_ACCUMULATOR,
> &data->cu_acc_power[cu]));
>
> WARN_ON(rdmsrl_safe(MSR_F15H_PTSC,
> &data->cpu_sw_pwr_ptsc[cu]));
> +
> + data->cu_on[cu] = 1;
> + mutex_unlock(&data->acc_pwr_mutex);
> }
>
> static int read_registers(struct fam15h_power_data *data)
> @@ -148,6 +159,10 @@ static int read_registers(struct fam15h_power_data *data)
> cores_per_cu = amd_get_cores_per_cu();
> cu_num = boot_cpu_data.x86_max_cores / cores_per_cu;
>
> + mutex_lock(&data->acc_pwr_mutex);
> + memset(data->cu_on, 0, sizeof(int) * MAX_CUS);
> + mutex_unlock(&data->acc_pwr_mutex);
> +
> WARN_ON_ONCE(cu_num > MAX_CUS);
>
> ret = zalloc_cpumask_var(&mask, GFP_KERNEL);
> @@ -184,18 +199,113 @@ 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, cores_per_cu, ret;
> + signed long leftover;
> +
> + cores_per_cu = amd_get_cores_per_cu();
> + cu_num = boot_cpu_data.x86_max_cores / cores_per_cu;
> +
> + ret = read_registers(data);
> + if (ret)
> + return 0;
> +
> + cu = 0;
> + while(cu++ < cu_num) {
> + prev_cu_acc_power[cu] = data->cu_acc_power[cu];
> + prev_ptsc[cu] = data->cpu_sw_pwr_ptsc[cu];
> + }

Please integrate checkpatch into your workflow of creating patches - it
can be correct sometimes:

ERROR: space required before the open parenthesis '('
#130: FILE: drivers/hwmon/fam15h_power.c:221:
+ while(cu++ < cu_num) {


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

This way of writing a function call is reaaally ugly. What's wrong with:

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

?

And don't tell me 80 columns - that rule is not a hard one.

> + if (leftover)
> + return 0;
> +

...

--
Regards/Gruss,
Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--


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