[Intel-gfx] [PATCH] drm/i915: add energy counter support for IVB

[Daniel Vetter]

On Wed, Jun 20, 2012 at 09:20:39AM +0300, Jani Nikula wrote:
> On Tue, 19 Jun 2012, Jesse Barnes <jbarnes at 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 at 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. ;)

And from the bikeshed departement: Can't we just print a running number? I
know, substraction is bloody hard, but for anything else than total power
consumption (e.g. graphing power over time) the running thing is imo
simpler. We've had the same discussion for the rc6 sysfs residency timers
and concluded (after Arjan yelled at us) that doing the substraction in
userspace is better, least it allows multiple userspace tools to read
this.

-Daniel

> 
> 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
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
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-- 
Daniel Vetter
Mail: daniel at ffwll.ch
Mobile: +41 (0)79 365 57 48