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

[Ben Widawsky <ben@bwidawsk.net>]

On Tue, 19 Jun 2012 13:20:50 -0700
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.

I'd like some more explanation of why this belongs in i915. Furthermore,
it seems like something which belongs in sysfs, not debugfs.

> 
> 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);
> +	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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-- 
Ben Widawsky, Intel Open Source Technology Center