Re: [PATCH 3/3] drm/i915: Drop locking/rpm resume/flush_delayed_work for cur/min/max freq sysfs read

Imre Deak
2016-03-16T18:07:11Z

On Fri, 2016-03-04 at 21:43 +0200, ville.syrjala@linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> cur_freq, min/max_freq_softlimit, efficient_freq are just single
> values
> stored under dev_priv.rps, so there's no real point in locking,
> resuming
> the devices and flushing the delayed resume work just to print them
> out.
>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

This makes things clearer, so would it make sense to still keep the
flush wq and leave out patch 4 until somebody benchmarks things? That
would address Tom's concern as well.

> ---
>  drivers/gpu/drm/i915/i915_sysfs.c | 84 ++++++-----------------------
> ----------
>  1 file changed, 13 insertions(+), 71 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_sysfs.c
> b/drivers/gpu/drm/i915/i915_sysfs.c
> index 2d576b7ff299..9e39d7a18fdb 100644
> --- a/drivers/gpu/drm/i915/i915_sysfs.c
> +++ b/drivers/gpu/drm/i915/i915_sysfs.c
> @@ -305,55 +305,6 @@ static ssize_t gt_act_freq_mhz_show(struct
> device *kdev,
>   return snprintf(buf, PAGE_SIZE, "%d\n", ret);
>  }
>
> -static ssize_t gt_cur_freq_mhz_show(struct device *kdev,
> -     struct device_attribute *attr,
> char *buf)
> -{
> - struct drm_minor *minor = dev_to_drm_minor(kdev);
> - struct drm_device *dev = minor->dev;
> - struct drm_i915_private *dev_priv = dev->dev_private;
> - int ret;
> -
> - flush_delayed_work(&dev_priv->rps.delayed_resume_work);
> -
> - intel_runtime_pm_get(dev_priv);
> -
> - mutex_lock(&dev_priv->rps.hw_lock);
> - ret = intel_gpu_freq(dev_priv, dev_priv->rps.cur_freq);
> - mutex_unlock(&dev_priv->rps.hw_lock);
> -
> - intel_runtime_pm_put(dev_priv);
> -
> - return snprintf(buf, PAGE_SIZE, "%d\n", ret);
> -}
> -
> -static ssize_t vlv_rpe_freq_mhz_show(struct device *kdev,
> -      struct device_attribute *attr,
> char *buf)
> -{
> - struct drm_minor *minor = dev_to_drm_minor(kdev);
> - struct drm_device *dev = minor->dev;
> - struct drm_i915_private *dev_priv = dev->dev_private;
> -
> - return snprintf(buf, PAGE_SIZE,
> - "%d\n",
> - intel_gpu_freq(dev_priv, dev_priv-
> >rps.efficient_freq));
> -}
> -
> -static ssize_t gt_max_freq_mhz_show(struct device *kdev, struct
> device_attribute *attr, char *buf)
> -{
> - struct drm_minor *minor = dev_to_drm_minor(kdev);
> - struct drm_device *dev = minor->dev;
> - struct drm_i915_private *dev_priv = dev->dev_private;
> - int ret;
> -
> - flush_delayed_work(&dev_priv->rps.delayed_resume_work);
> -
> - mutex_lock(&dev_priv->rps.hw_lock);
> - ret = intel_gpu_freq(dev_priv, dev_priv-
> >rps.max_freq_softlimit);
> - mutex_unlock(&dev_priv->rps.hw_lock);
> -
> - return snprintf(buf, PAGE_SIZE, "%d\n", ret);
> -}
> -
>  static ssize_t gt_max_freq_mhz_store(struct device *kdev,
>        struct device_attribute *attr,
>        const char *buf, size_t count)
> @@ -406,22 +357,6 @@ static ssize_t gt_max_freq_mhz_store(struct
> device *kdev,
>   return count;
>  }
>
> -static ssize_t gt_min_freq_mhz_show(struct device *kdev, struct
> device_attribute *attr, char *buf)
> -{
> - struct drm_minor *minor = dev_to_drm_minor(kdev);
> - struct drm_device *dev = minor->dev;
> - struct drm_i915_private *dev_priv = dev->dev_private;
> - int ret;
> -
> - flush_delayed_work(&dev_priv->rps.delayed_resume_work);
> -
> - mutex_lock(&dev_priv->rps.hw_lock);
> - ret = intel_gpu_freq(dev_priv, dev_priv-
> >rps.min_freq_softlimit);
> - mutex_unlock(&dev_priv->rps.hw_lock);
> -
> - return snprintf(buf, PAGE_SIZE, "%d\n", ret);
> -}
> -
>  static ssize_t gt_min_freq_mhz_store(struct device *kdev,
>        struct device_attribute *attr,
>        const char *buf, size_t count)
> @@ -472,16 +407,15 @@ static ssize_t gt_min_freq_mhz_store(struct
> device *kdev,
>  }
>
>  static DEVICE_ATTR(gt_act_freq_mhz, S_IRUGO, gt_act_freq_mhz_show,
> NULL);
> -static DEVICE_ATTR(gt_cur_freq_mhz, S_IRUGO, gt_cur_freq_mhz_show,
> NULL);
> -static DEVICE_ATTR(gt_max_freq_mhz, S_IRUGO | S_IWUSR,
> gt_max_freq_mhz_show, gt_max_freq_mhz_store);
> -static DEVICE_ATTR(gt_min_freq_mhz, S_IRUGO | S_IWUSR,
> gt_min_freq_mhz_show, gt_min_freq_mhz_store);
> -
> -static DEVICE_ATTR(vlv_rpe_freq_mhz, S_IRUGO, vlv_rpe_freq_mhz_show,
> NULL);
>
>  static ssize_t gt_rp_mhz_show(struct device *kdev, struct
> device_attribute *attr, char *buf);
> +static DEVICE_ATTR(gt_cur_freq_mhz, S_IRUGO, gt_rp_mhz_show, NULL);
> +static DEVICE_ATTR(gt_max_freq_mhz, S_IRUGO | S_IWUSR,
> gt_rp_mhz_show, gt_max_freq_mhz_store);
> +static DEVICE_ATTR(gt_min_freq_mhz, S_IRUGO | S_IWUSR,
> gt_rp_mhz_show, gt_min_freq_mhz_store);
>  static DEVICE_ATTR(gt_RP0_freq_mhz, S_IRUGO, gt_rp_mhz_show, NULL);
>  static DEVICE_ATTR(gt_RP1_freq_mhz, S_IRUGO, gt_rp_mhz_show, NULL);
>  static DEVICE_ATTR(gt_RPn_freq_mhz, S_IRUGO, gt_rp_mhz_show, NULL);
> +static DEVICE_ATTR(vlv_rpe_freq_mhz, S_IRUGO, gt_rp_mhz_show, NULL);
>
>  /* For now we have a static number of RP states */
>  static ssize_t gt_rp_mhz_show(struct device *kdev, struct
> device_attribute *attr, char *buf)
> @@ -491,12 +425,20 @@ static ssize_t gt_rp_mhz_show(struct device
> *kdev, struct device_attribute *attr
>   struct drm_i915_private *dev_priv = dev->dev_private;
>   u32 val;
>
> - if (attr == &dev_attr_gt_RP0_freq_mhz)
> + if (attr == &dev_attr_gt_cur_freq_mhz)
> + val = intel_gpu_freq(dev_priv, dev_priv-
> >rps.cur_freq);
> + else if (attr == &dev_attr_gt_max_freq_mhz)
> + val = intel_gpu_freq(dev_priv, dev_priv-
> >rps.max_freq_softlimit);
> + else if (attr == &dev_attr_gt_min_freq_mhz)
> + val = intel_gpu_freq(dev_priv, dev_priv-
> >rps.min_freq_softlimit);
> + else if (attr == &dev_attr_gt_RP0_freq_mhz)
>   val = intel_gpu_freq(dev_priv, dev_priv-
> >rps.rp0_freq);
>   else if (attr == &dev_attr_gt_RP1_freq_mhz)
>   val = intel_gpu_freq(dev_priv, dev_priv-
> >rps.rp1_freq);
>   else if (attr == &dev_attr_gt_RPn_freq_mhz)
>   val = intel_gpu_freq(dev_priv, dev_priv-
> >rps.min_freq);
> + else if (attr == &dev_attr_vlv_rpe_freq_mhz)
> + val = intel_gpu_freq(dev_priv, dev_priv-
> >rps.efficient_freq);
>   else
>   BUG();