[Mesa-dev] [PATCH] st/mesa: exit the update fragment samplers/textures loops early.

[Brian Paul]

On 02/08/2012 07:28 AM, Dave Airlie wrote:
> From: Dave Airlie<airlied at redhat.com>
>
> If we have no more enabled samplers and we've reset all the previously
> used ones, no need to keep going around this loop.
>
> Signed-off-by: Dave Airlie<airlied at redhat.com>
> ---
>   src/mesa/state_tracker/st_atom_sampler.c |   12 ++++++++----
>   src/mesa/state_tracker/st_atom_texture.c |   12 +++++++++---
>   2 files changed, 17 insertions(+), 7 deletions(-)
>
> diff --git a/src/mesa/state_tracker/st_atom_sampler.c b/src/mesa/state_tracker/st_atom_sampler.c
> index 8845fed..6524949 100644
> --- a/src/mesa/state_tracker/st_atom_sampler.c
> +++ b/src/mesa/state_tracker/st_atom_sampler.c
> @@ -233,15 +233,16 @@ update_fragment_samplers(struct st_context *st)
>      const struct gl_context *ctx = st->ctx;
>      struct gl_fragment_program *fprog = ctx->FragmentProgram._Current;
>      GLuint su;
> +   GLuint samplers_used = fprog->Base.SamplersUsed;
> +   GLuint old_max = st->state.num_samplers;
>
>      st->state.num_samplers = 0;
>
>      /* loop over sampler units (aka tex image units) */
> -   for (su = 0; su<  ctx->Const.MaxTextureImageUnits; su++) {
> +   for (su = 0; su<  ctx->Const.MaxTextureImageUnits; su++, samplers_used>>= 1) {
>         struct pipe_sampler_state *sampler = st->state.samplers + su;
>
> -
> -      if (fprog->Base.SamplersUsed&  (1<<  su)) {
> +      if (samplers_used&  1) {
>            GLuint texUnit;
>
>   	 texUnit = fprog->Base.SamplerUnits[su];
> @@ -253,7 +254,10 @@ update_fragment_samplers(struct st_context *st)
>            /*printf("%s su=%u non-null\n", __FUNCTION__, su);*/
>            cso_single_sampler(st->cso_context, su, sampler);
>         }
> -      else {
> +      else if (samplers_used == 0&&  su>= old_max) {
> +         /* if we've reset all the old views and we have no more new ones */
> +         break;
> +      } else {
>            /*printf("%s su=%u null\n", __FUNCTION__, su);*/
>            cso_single_sampler(st->cso_context, su, NULL);
>         }
> diff --git a/src/mesa/state_tracker/st_atom_texture.c b/src/mesa/state_tracker/st_atom_texture.c
> index d241527..9e98d7f 100644
> --- a/src/mesa/state_tracker/st_atom_texture.c
> +++ b/src/mesa/state_tracker/st_atom_texture.c
> @@ -300,13 +300,16 @@ update_fragment_textures(struct st_context *st)
>      const struct gl_context *ctx = st->ctx;
>      struct gl_fragment_program *fprog = ctx->FragmentProgram._Current;
>      GLuint su;
> +   int old_max = st->state.num_textures;
> +   GLbitfield samplers_used = fprog->Base.SamplersUsed;
>
>      st->state.num_textures = 0;
>
>      /* loop over sampler units (aka tex image units) */
> -   for (su = 0; su<  ctx->Const.MaxTextureImageUnits; su++) {
> +   for (su = 0; su<  ctx->Const.MaxTextureImageUnits; su++, samplers_used>>= 1) {
>         struct pipe_sampler_view *sampler_view = NULL;
> -      if (fprog->Base.SamplersUsed&  (1<<  su)) {
> +
> +      if (samplers_used&  1) {
>            GLboolean retval;
>            GLuint texUnit;
>
> @@ -317,7 +320,10 @@ update_fragment_textures(struct st_context *st)
>   	    continue;
>
>            st->state.num_textures = su + 1;
> -      }
> +      } else if (samplers_used == 0&&  su>= old_max)
> +         /* if we've reset all the old views and we have no more new ones */
> +         break;
> +

Just a minor nit: would you mind putting braces there?


>         pipe_sampler_view_reference(&st->state.sampler_views[su], sampler_view);
>      }
>


Reviewed-by: Brian Paul <brianp at vmware.com>


BTW, if you're looking for something else to optimize in the state 
validation code, look at the calls to st_finalize_texture().

We're calling it both from the update_single_texture() function used 
for vert/frag tex validation AND from finalize_textures().  The later 
was added to deal with an OOM condition, IIRC.  I think the results of 
finalize_textures() could be saved to avoid calling 
st_finalize_texture() in the vert/frag validation code.

In any case, st_finalize_texture() should be smarter too. I think we 
could have some sort of per-texture dirty flag to avoid redundant 
validation.

-Brian