[Intel-gfx] [RFC 02/11] drm/i915: Add intel_energy_uJ

[Tvrtko Ursulin]

On 14/09/2017 21:36, Ville Syrjälä wrote:
> On Mon, Sep 11, 2017 at 04:25:50PM +0100, Tvrtko Ursulin wrote:
>> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>>
>> Extract code from i915_energy_uJ (debugfs) so it can be used by
>> other callers in future patches.
>>
>> v2: Rebase.
>>
>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>> ---
>>   drivers/gpu/drm/i915/i915_debugfs.c | 17 +----------------
>>   drivers/gpu/drm/i915/i915_drv.h     |  2 ++
>>   drivers/gpu/drm/i915/intel_pm.c     | 25 +++++++++++++++++++++++++
>>   3 files changed, 28 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
>> index 6338018f655d..b3a4a66bf7c4 100644
>> --- a/drivers/gpu/drm/i915/i915_debugfs.c
>> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
>> @@ -2780,26 +2780,11 @@ static int i915_sink_crc(struct seq_file *m, void *data)
>>   static int i915_energy_uJ(struct seq_file *m, void *data)
>>   {
>>   	struct drm_i915_private *dev_priv = node_to_i915(m->private);
>> -	unsigned long long power;
>> -	u32 units;
>>   
>>   	if (INTEL_GEN(dev_priv) < 6)
>>   		return -ENODEV;
>>   
>> -	intel_runtime_pm_get(dev_priv);
>> -
>> -	if (rdmsrl_safe(MSR_RAPL_POWER_UNIT, &power)) {
>> -		intel_runtime_pm_put(dev_priv);
>> -		return -ENODEV;
>> -	}
>> -
>> -	units = (power & 0x1f00) >> 8;
>> -	power = I915_READ(MCH_SECP_NRG_STTS);
>> -	power = (1000000 * power) >> units; /* convert to uJ */
>> -
>> -	intel_runtime_pm_put(dev_priv);
>> -
>> -	seq_printf(m, "%llu", power);
>> +	seq_printf(m, "%llu", intel_energy_uJ(dev_priv));
> 
> Isn't this the same thing as the package energy you get from rapl? Can't
> we just nuke this private implementation entirely and rely on whatever
> rapl gives us?

If so I think we could leave it out of i915 PMU. I tried looking for 
MCH_SECP_NRG_STTS in bspec but did not find it though? Is your bspec fu 
perhaps better and you could have a look?

I can also compare the outputs of the two and see if they are one and 
the same that way.

Regards,

Tvrtko