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

Ville Syrjälä
2017-09-15T10:34:07Z

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).

--
Ville Syrjälä
Intel OTC