[PATCH] drm/amd/amdgpu: Add a GPU_LOAD entry to sysfs (v2)

[Christian König]

Am 20.06.2018 um 18:48 schrieb Tom St Denis:
> This adds what should be a stable interface to read GPU
> load from userspace.
>
> (v2): Fix comments and name of file per recommendations.
>
> Signed-off-by: Tom St Denis <tom.stdenis at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c | 47 ++++++++++++++++++++++++++++++++++
>   1 file changed, 47 insertions(+)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
> index 113edffb5960..49138ac2be24 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_pm.c
> @@ -918,6 +918,43 @@ static ssize_t amdgpu_set_pp_power_profile_mode(struct device *dev,
>   	return -EINVAL;
>   }
>   
> +/**
> + * DOC: busy_percent
> + *
> + * The firmware computes a percentage of load based on the activity
> + * level in the IP cores.
> + */
> +static ssize_t amdgpu_get_busy_percent(struct device *dev,
> +		struct device_attribute *attr,
> +		char *buf)
> +{
> +	struct drm_device *ddev = dev_get_drvdata(dev);
> +	struct amdgpu_device *adev = ddev->dev_private;
> +	int r, value, size = sizeof(value);
> +
> +	/* sanity check PP is enabled */
> +	if (!(adev->powerplay.pp_funcs &&
> +	      adev->powerplay.pp_funcs->read_sensor))
> +		return -EINVAL;
> +
> +	/* read the IP busy sensor */
> +	r = amdgpu_dpm_read_sensor(adev, AMDGPU_PP_SENSOR_GPU_LOAD,
> +				   (void *)&value, &size);
> +	if (r)
> +		return r;
> +
> +	return snprintf(buf, PAGE_SIZE, "%d\n", value);
> +}
> +
> +static ssize_t amdgpu_set_busy_percent(struct device *dev,
> +		struct device_attribute *attr,
> +		const char *buf,
> +		size_t count)
> +{
> +	return -EINVAL;
> +}
> +
> +

For read only attributes the set function can be specified as NULL as well.

Apart from that this looks good to me,
Christian.

>   static DEVICE_ATTR(power_dpm_state, S_IRUGO | S_IWUSR, amdgpu_get_dpm_state, amdgpu_set_dpm_state);
>   static DEVICE_ATTR(power_dpm_force_performance_level, S_IRUGO | S_IWUSR,
>   		   amdgpu_get_dpm_forced_performance_level,
> @@ -951,6 +988,8 @@ static DEVICE_ATTR(pp_power_profile_mode, S_IRUGO | S_IWUSR,
>   static DEVICE_ATTR(pp_od_clk_voltage, S_IRUGO | S_IWUSR,
>   		amdgpu_get_pp_od_clk_voltage,
>   		amdgpu_set_pp_od_clk_voltage);
> +static DEVICE_ATTR(gpu_busy_percent, S_IRUGO | S_IWUSR,
> +		amdgpu_get_busy_percent, amdgpu_set_busy_percent);
>   
>   static ssize_t amdgpu_hwmon_show_temp(struct device *dev,
>   				      struct device_attribute *attr,
> @@ -1854,6 +1893,13 @@ int amdgpu_pm_sysfs_init(struct amdgpu_device *adev)
>   				"pp_od_clk_voltage\n");
>   		return ret;
>   	}
> +	ret = device_create_file(adev->dev,
> +			&dev_attr_gpu_busy_percent);
> +	if (ret) {
> +		DRM_ERROR("failed to create device file	"
> +				"gpu_busy_level\n");
> +		return ret;
> +	}
>   	ret = amdgpu_debugfs_pm_init(adev);
>   	if (ret) {
>   		DRM_ERROR("Failed to register debugfs file for dpm!\n");
> @@ -1889,6 +1935,7 @@ void amdgpu_pm_sysfs_fini(struct amdgpu_device *adev)
>   			&dev_attr_pp_power_profile_mode);
>   	device_remove_file(adev->dev,
>   			&dev_attr_pp_od_clk_voltage);
> +	device_remove_file(adev->dev, &dev_attr_gpu_busy_percent);
>   }
>   
>   void amdgpu_pm_compute_clocks(struct amdgpu_device *adev)