Re: [PATCH 1/1] drm/i915: Tracepoints for profiling DC9 entry and exit programming

From: Sagar Arun Kamble <sagar.a.kamble@intel.com>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 1/1] drm/i915: Tracepoints for profiling DC9 entry and exit programming
Date: Sun, 21 Jun 2015 10:20:09 +0530	[thread overview]
Message-ID: <1434862209.30388.3.camel@sakamble-desktop> (raw)
In-Reply-To: <20150617113009.GG23637@phenom.ffwll.local>

On Wed, 2015-06-17 at 13:30 +0200, Daniel Vetter wrote:
> On Wed, Jun 17, 2015 at 04:21:10PM +0530, Sagar Arun Kamble wrote:
> > DC9 entry and exit programming is critical part of suspend/resume
> > sequences. This patch adds tracepoints that can help analyze time
> > taken using analyze_suspend.py/FTrace.
> > 
> > Change-Id: I22fca5313c4349f8937eeb5a1c441c8ef76e5f4e
> > Signed-off-by: Sagar Arun Kamble <sagar.a.kamble@intel.com>
> 
> Tracepoints are for system profiling when benchmarking and all that. What
> exactly is this here for?
Hi Daniel,
These trace points are added so that we can know how much time is spent
in entry/exit programming of DC9 state which is done during
runtime/system suspend. Analyzing these times is critical for resume
time KPIs.

> Also note that tracepoints are pretty much ABI, so high standards apply
> here.
Already these tracepoints are present at PM Core level.
> -Daniel
> 
> > ---
> >  drivers/gpu/drm/i915/i915_drv.c | 9 +++++++++
> >  drivers/gpu/drm/i915/i915_reg.h | 1 +
> >  2 files changed, 10 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
> > index 78ef0bb..6797650 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.c
> > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > @@ -39,6 +39,7 @@
> >  #include <linux/module.h>
> >  #include <linux/pm_runtime.h>
> >  #include <drm/drm_crtc_helper.h>
> > +#include <trace/events/power.h>
> >  
> >  static struct drm_driver driver;
> >  
> > @@ -1061,12 +1062,16 @@ static int bxt_suspend_complete(struct drm_i915_private *dev_priv)
> >  {
> >  	struct drm_device *dev = dev_priv->dev;
> >  
> > +	trace_suspend_resume(TPS("dc_state_entry"), DC9_STATE, true);
> > +
> >  	/* TODO: when DC5 support is added disable DC5 here. */
> >  
> >  	broxton_ddi_phy_uninit(dev);
> >  	broxton_uninit_cdclk(dev);
> >  	bxt_enable_dc9(dev_priv);
> >  
> > +	trace_suspend_resume(TPS("dc_state_entry"), DC9_STATE, false);
> > +
> >  	return 0;
> >  }
> >  
> > @@ -1076,6 +1081,8 @@ static int bxt_resume_prepare(struct drm_i915_private *dev_priv)
> >  
> >  	/* TODO: when CSR FW support is added make sure the FW is loaded */
> >  
> > +	trace_suspend_resume(TPS("dc_state_exit"), DC9_STATE, true);
> > +
> >  	bxt_disable_dc9(dev_priv);
> >  
> >  	/*
> > @@ -1086,6 +1093,8 @@ static int bxt_resume_prepare(struct drm_i915_private *dev_priv)
> >  	broxton_ddi_phy_init(dev);
> >  	intel_prepare_ddi(dev);
> >  
> > +	trace_suspend_resume(TPS("dc_state_exit"), DC9_STATE, false);
> > +
> >  	return 0;
> >  }
> >  
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index 0b979ad..cf83ec8 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -7290,6 +7290,7 @@ enum skl_disp_power_wells {
> >  #define  DC_STATE_EN_DC9		(1<<3)
> >  #define  DC_STATE_EN_UPTO_DC6		(2<<0)
> >  #define  DC_STATE_EN_UPTO_DC5_DC6_MASK   0x3
> > +#define  DC9_STATE			9
> >  
> >  #define  DC_STATE_DEBUG                  0x45520
> >  #define  DC_STATE_DEBUG_MASK_MEMORY_UP	(1<<1)
> > -- 
> > 1.9.1
> > 
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 


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