[Mesa-dev] [PATCH 2/3] mesa: build up a mask of active shader stages in a pipeline

[Timothy Arceri]

On Tue, 2015-12-08 at 15:21 +1100, Timothy Arceri wrote:
> On Tue, 2015-12-08 at 10:55 +1100, Timothy Arceri wrote:
> > On Mon, 2015-12-07 at 11:29 +0200, Tapani Pälli wrote:
> > > This will be used for validating SSO pipeline where all active
> > > stages
> > > in linked programs should be in use when rendering.
> > > 
> > > Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
> > > ---
> > >  src/mesa/main/mtypes.h      |  2 ++
> > >  src/mesa/main/pipelineobj.c | 39
> > > +++++++++++++++++++++++++++++++++++++++
> > >  2 files changed, 41 insertions(+)
> > > 
> > > diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
> > > index fa7ead0..d5a22c9 100644
> > > --- a/src/mesa/main/mtypes.h
> > > +++ b/src/mesa/main/mtypes.h
> > > @@ -2824,6 +2824,8 @@ struct gl_pipeline_object
> > >     GLboolean Validated;                 /**< Pipeline Validation
> > > status */
> > >  
> > >     GLchar *InfoLog;
> > > +
> > > +   uint8_t ActiveStages;                /**< Stages used,
> > > (glUseProgramStages) */
> > >  };
> > >  
> > >  /**
> > > diff --git a/src/mesa/main/pipelineobj.c
> > > b/src/mesa/main/pipelineobj.c
> > > index 6710d0d..c510ee8 100644
> > > --- a/src/mesa/main/pipelineobj.c
> > > +++ b/src/mesa/main/pipelineobj.c
> > > @@ -218,6 +218,43 @@ _mesa_reference_pipeline_object_(struct
> > > gl_context *ctx,
> > >     }
> > >  }
> > >  
> > > +static GLenum
> > > +shader_bit_from_shader_stage(gl_shader_stage stage)
> > > +{
> > > +   switch (stage) {
> > > +   case MESA_SHADER_VERTEX:
> > > +      return GL_VERTEX_SHADER_BIT;
> > > +   case MESA_SHADER_FRAGMENT:
> > > +      return GL_FRAGMENT_SHADER_BIT;
> > > +   case MESA_SHADER_GEOMETRY:
> > > +      return GL_GEOMETRY_SHADER_BIT;
> > > +   case MESA_SHADER_TESS_CTRL:
> > > +      return GL_TESS_CONTROL_SHADER_BIT;
> > > +   case MESA_SHADER_TESS_EVAL:
> > > +      return GL_TESS_EVALUATION_SHADER_BIT;
> > > +   case MESA_SHADER_COMPUTE:
> > > +      return GL_COMPUTE_SHADER_BIT;
> > > +   default:
> > > +      unreachable("bad value in
> > > _mesa_shader_bit_from_shader_stage()");
> > > +   }
> > > +}
> > > +
> > > +static void
> > > +update_active_pipeline_stages(struct gl_pipeline_object *pipe,
> > > +                              struct gl_shader_program *shProg,
> > > +                              GLbitfield stages)
> > > +{
> > > +   unsigned i;
> > > +   for (i = 0; i < MESA_SHADER_STAGES; i++) {
> > > +      if ((stages & shader_bit_from_shader_stage(i)) != 0) {
> > > +         if (shProg && shProg->ActiveStages & (1 << i))
> > > +            pipe->ActiveStages |= (1 << i);
> > > +         else
> > > +            pipe->ActiveStages &= ~(1 << i);
> > > +      }
> > > +   }
> > 
> > I think you could do most of the validation at this point which
> > would
> > reduce the amount of work required during rendering. You also have
> > forgotten about GL_ALL_SHADER_BITS.
> 
> No you didn't I was just looking at to code for to long :P However
> unless I'm missing something I believe my other comments are still
> valid.
> 
> > 
> > For example could you do something like this? 
> > 
> > Note: You would need to call this function after the
> >  _mesa_use_shader_program() calls.
> > 
> > unsigned i;
> > unsigned j;     
> > 
> > for (i = 0; i < MESA_SHADER_STAGES; i++) {
> >    if (!pipe->CurrentProgram[i]) {
> >       struct gl_shader_program *shProg = pipe->CurrentProgram[i];
> >       for (j = 0; j < MESA_SHADER_STAGES; j++) {
> >          if (!shProg->_LinkedShaders[j])
> >          continue;
> > 
> >          /* Make sure that any shader stage is also used in the
> > pipeline */
> >          if (shProg != pipe->CurrentProgram[j]) {
> >             pipe->ValidProgramUse = false;
> >             return;
> >          }
> >       }
> >    }
> > 
> >    pipe->ValidProgramUse = true;
> > }

Thinking about this some more you would also need to revalidate if the
program has been relinked. I guess ValidProgramUse could be stored for
each program object rather than just for the pipe, then you could loop
over the stages in patch 3 and only do the full validation check when
 ValidProgramUse is false (you would reset to false on a relink).

I'm also just about to add another comment to patch 3 as I think your c
urrent patch will miss some use cases.

> > 
> > > +}
> > > +
> > >  /**
> > >   * Bound program to severals stages of the pipeline
> > >   */
> > > @@ -311,6 +348,8 @@ _mesa_UseProgramStages(GLuint pipeline,
> > > GLbitfield stages, GLuint program)
> > >        }
> > >     }
> > >  
> > > +   update_active_pipeline_stages(pipe, shProg, stages);
> > > +
> > >     /* Enable individual stages from the program as requested by
> > > the
> > >      * application.  If there is no shader for a requested stage
> > > in
> > > the
> > >      * program, _mesa_use_shader_program will enable fixed
> > > -function
> > > processing
> > _______________________________________________
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> > mesa-dev at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/mesa-dev
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