Re: [RFC 02/11] drm/i915: Add intel_energy_uJ

Tvrtko Ursulin
2017-09-15T11:16:52Z

On 15/09/2017 11:38, Chris Wilson wrote:
> Quoting Ville Syrjälä (2017-09-15 11:34:03)
>> On Fri, Sep 15, 2017 at 11:07:21AM +0100, Tvrtko Ursulin wrote:
>>>
>>> On 15/09/2017 09:51, Chris Wilson wrote:
>>>> Quoting Tvrtko Ursulin (2017-09-15 07:56:00)
>>>>>
>>>>> 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@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@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 had it there for the convenience of grabbing everything through the
>>>> one interface (which I still think has merit). I don't I ever compiled
>>>> in the rapl user interface...
>>>
>>> You mean the RAPL PMU, PERF_EVENTS_INTEL_RAPL?
>>
>> I suspect he means sysfs. IIRC this perf+rapl marriage is somewhat
>> recent (or at least I still remeber having to fix it when it was
>> introduced because it broke the sysfs interface).
>
> I hadn't even heard of the perf interface. Yes, if it is available
> through perf, that's just what we want.

Dropping it then. And I've checked in the meantime it is reporting
identical numbers to power/energy-gpu/ provided by the intel_rapl_perf
module.

Regards,

Tvrtko