Re: [PATCH] drm/i915: add energy counter support for IVB

[Jani Nikula <jani.nikula@linux.intel.com>]

On Tue, 19 Jun 2012, Jesse Barnes <jbarnes@virtuousgeek.org> wrote:
> On SNB and IVB, there's an MSR (also exposed through MCHBAR) we can use
> to read out the amount of energy used over time.  Expose this in debugfs
> to make it easy to do power comparisons with different configurations.
>
> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
>
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index c0b7688..c8998b4 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -1897,6 +1897,41 @@ static const struct file_operations i915_cache_sharing_fops = {
>  	.llseek = default_llseek,
>  };
>  
> +#define MSR_IA32_PACKAGE_POWER_SKU_UNIT		0x00000606
> +
> +static int
> +i915_energy_status(struct seq_file *m, void *data)
> +{
> +	struct drm_info_node *node = (struct drm_info_node *) m->private;
> +	struct drm_device *dev = node->minor->dev;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +	u64 ppsu;
> +	u32 val, diff, units;
> +
> +	if (!(IS_GEN6(dev) || IS_GEN7(dev))) {
> +		seq_printf(m, "Unsupported platform\n");
> +		return 0;
> +	}
> +
> +	rdmsrl(MSR_IA32_PACKAGE_POWER_SKU_UNIT, ppsu);
> +
> +	ppsu = (ppsu & 0x1f00) >> 8;
> +
> +	units = 1000000 / (1 << ppsu); /* convert to uJ */
> +
> +	mutex_lock(&dev->struct_mutex);
> +	val = I915_READ(SECP_NRG_STTS);
> +	if (val < dev_priv->last_secp)
> +		diff = val + (0xffffffff - dev_priv->last_secp);

>From the nitpickery dept.: I think that's off-by-one. But nobody will
ever notice from the output. ;)

Jani.


> +	else
> +		diff = val - dev_priv->last_secp;
> +	dev_priv->last_secp = val;
> +	seq_printf(m, "Energy since last read: %u uJ\n", diff * units);
> +	mutex_unlock(&dev->struct_mutex);
> +
> +	return 0;
> +}
> +
>  /* As the drm_debugfs_init() routines are called before dev->dev_private is
>   * allocated we need to hook into the minor for release. */
>  static int
> @@ -2035,6 +2070,7 @@ static struct drm_info_list i915_debugfs_list[] = {
>  	{"i915_swizzle_info", i915_swizzle_info, 0},
>  	{"i915_ppgtt_info", i915_ppgtt_info, 0},
>  	{"i915_dpio", i915_dpio_info, 0},
> +	{"i915_energy", i915_energy_status, 0},
>  };
>  #define I915_DEBUGFS_ENTRIES ARRAY_SIZE(i915_debugfs_list)
>  
> @@ -2102,6 +2138,8 @@ void i915_debugfs_cleanup(struct drm_minor *minor)
>  				 1, minor);
>  	drm_debugfs_remove_files((struct drm_info_list *) &i915_ring_stop_fops,
>  				 1, minor);
> +	drm_debugfs_remove_files((struct drm_info_list *) &i915_error_state_fops,
> +				 1, minor);
>  }
>  
>  #endif /* CONFIG_DEBUG_FS */
> diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
> index 11c7a6a..fb07415 100644
> --- a/drivers/gpu/drm/i915/i915_drv.h
> +++ b/drivers/gpu/drm/i915/i915_drv.h
> @@ -802,6 +802,8 @@ typedef struct drm_i915_private {
>  	u8 corr;
>  	spinlock_t *mchdev_lock;
>  
> +	u32 last_secp;
> +
>  	enum no_fbc_reason no_fbc_reason;
>  
>  	struct drm_mm_node *compressed_fb;
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index 0f45a18..b7d1310 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -1219,6 +1219,8 @@
>  #define CLKCFG_MEM_800					(3 << 4)
>  #define CLKCFG_MEM_MASK					(7 << 4)
>  
> +#define SECP_NRG_STTS			(MCHBAR_MIRROR_BASE_SNB + 0x592c)
> +
>  #define TSC1			0x11001
>  #define   TSE			(1<<0)
>  #define TR1			0x11006
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