[Mesa-dev] [PATCH 5/5] radeonsi: allow out-of-order rasterization in commutative blending cases

Marek Olšák maraeo at gmail.com
Thu Sep 14 00:18:40 UTC 2017


For the series:

Reviewed-by: Marek Olšák <marek.olsak at amd.com>

Marek

On Sat, Sep 9, 2017 at 12:43 PM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
>
> We do not enable this by default for additive blending, since it slightly
> breaks OpenGL invariance guarantees due to non-determinism.
>
> Still, there may be some applications can benefit from white-listing
> via the radeonsi_commutative_blend_add drirc setting without any real
> visible artifacts.
> ---
>  src/gallium/drivers/radeonsi/driinfo_radeonsi.h |  1 +
>  src/gallium/drivers/radeonsi/si_pipe.c          |  2 +
>  src/gallium/drivers/radeonsi/si_pipe.h          |  1 +
>  src/gallium/drivers/radeonsi/si_state.c         | 67 +++++++++++++++++++++++--
>  src/gallium/drivers/radeonsi/si_state.h         |  1 +
>  src/util/xmlpool/t_options.h                    |  5 ++
>  6 files changed, 73 insertions(+), 4 deletions(-)
>
> diff --git a/src/gallium/drivers/radeonsi/driinfo_radeonsi.h b/src/gallium/drivers/radeonsi/driinfo_radeonsi.h
> index 8be85289a0c..989e5175cc0 100644
> --- a/src/gallium/drivers/radeonsi/driinfo_radeonsi.h
> +++ b/src/gallium/drivers/radeonsi/driinfo_radeonsi.h
> @@ -1,5 +1,6 @@
>  // DriConf options specific to radeonsi
>  DRI_CONF_SECTION_PERFORMANCE
>      DRI_CONF_RADEONSI_ENABLE_SISCHED("false")
>      DRI_CONF_RADEONSI_ASSUME_NO_Z_FIGHTS("false")
> +    DRI_CONF_RADEONSI_COMMUTATIVE_BLEND_ADD("false")
>  DRI_CONF_SECTION_END
> diff --git a/src/gallium/drivers/radeonsi/si_pipe.c b/src/gallium/drivers/radeonsi/si_pipe.c
> index b4972be739c..c44ea3be740 100644
> --- a/src/gallium/drivers/radeonsi/si_pipe.c
> +++ b/src/gallium/drivers/radeonsi/si_pipe.c
> @@ -1043,20 +1043,22 @@ struct pipe_screen *radeonsi_screen_create(struct radeon_winsys *ws,
>                 (sscreen->b.chip_class == SI &&
>                  sscreen->b.info.pfp_fw_version >= 79 &&
>                  sscreen->b.info.me_fw_version >= 142);
>
>         sscreen->has_ds_bpermute = sscreen->b.chip_class >= VI;
>         sscreen->has_out_of_order_rast = sscreen->b.chip_class >= VI &&
>                                          sscreen->b.info.max_se >= 2 &&
>                                          !(sscreen->b.debug_flags & DBG_NO_OUT_OF_ORDER);
>         sscreen->assume_no_z_fights =
>                 driQueryOptionb(config->options, "radeonsi_assume_no_z_fights");
> +       sscreen->commutative_blend_add =
> +               driQueryOptionb(config->options, "radeonsi_commutative_blend_add");
>         sscreen->has_msaa_sample_loc_bug = (sscreen->b.family >= CHIP_POLARIS10 &&
>                                             sscreen->b.family <= CHIP_POLARIS12) ||
>                                            sscreen->b.family == CHIP_VEGA10 ||
>                                            sscreen->b.family == CHIP_RAVEN;
>         sscreen->dpbb_allowed = sscreen->b.chip_class >= GFX9 &&
>                                 !(sscreen->b.debug_flags & DBG_NO_DPBB);
>         sscreen->dfsm_allowed = sscreen->dpbb_allowed &&
>                                 !(sscreen->b.debug_flags & DBG_NO_DFSM);
>
>         /* While it would be nice not to have this flag, we are constrained
> diff --git a/src/gallium/drivers/radeonsi/si_pipe.h b/src/gallium/drivers/radeonsi/si_pipe.h
> index d200c9f571f..27e2bc81172 100644
> --- a/src/gallium/drivers/radeonsi/si_pipe.h
> +++ b/src/gallium/drivers/radeonsi/si_pipe.h
> @@ -90,20 +90,21 @@ struct u_suballocator;
>  struct si_screen {
>         struct r600_common_screen       b;
>         unsigned                        gs_table_depth;
>         unsigned                        tess_offchip_block_dw_size;
>         bool                            has_clear_state;
>         bool                            has_distributed_tess;
>         bool                            has_draw_indirect_multi;
>         bool                            has_ds_bpermute;
>         bool                            has_out_of_order_rast;
>         bool                            assume_no_z_fights;
> +       bool                            commutative_blend_add;
>         bool                            has_msaa_sample_loc_bug;
>         bool                            dpbb_allowed;
>         bool                            dfsm_allowed;
>         bool                            llvm_has_working_vgpr_indexing;
>
>         /* Whether shaders are monolithic (1-part) or separate (3-part). */
>         bool                            use_monolithic_shaders;
>         bool                            record_llvm_ir;
>
>         mtx_t                   shader_parts_mutex;
> diff --git a/src/gallium/drivers/radeonsi/si_state.c b/src/gallium/drivers/radeonsi/si_state.c
> index a8af5752771..6a063e7f7a6 100644
> --- a/src/gallium/drivers/radeonsi/si_state.c
> +++ b/src/gallium/drivers/radeonsi/si_state.c
> @@ -370,20 +370,62 @@ static uint32_t si_translate_blend_opt_factor(int blend_fact, bool is_alpha)
>         case PIPE_BLENDFACTOR_INV_SRC_ALPHA:
>                 return V_028760_BLEND_OPT_PRESERVE_A0_IGNORE_A1;
>         case PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE:
>                 return is_alpha ? V_028760_BLEND_OPT_PRESERVE_ALL_IGNORE_NONE
>                                 : V_028760_BLEND_OPT_PRESERVE_NONE_IGNORE_A0;
>         default:
>                 return V_028760_BLEND_OPT_PRESERVE_NONE_IGNORE_NONE;
>         }
>  }
>
> +static void si_blend_check_commutativity(struct si_screen *sscreen,
> +                                        struct si_state_blend *blend,
> +                                        enum pipe_blend_func func,
> +                                        enum pipe_blendfactor src,
> +                                        enum pipe_blendfactor dst,
> +                                        unsigned chanmask)
> +{
> +       /* Src factor is allowed when it does not depend on Dst */
> +       static const uint32_t src_allowed =
> +               (1u << PIPE_BLENDFACTOR_ONE) |
> +               (1u << PIPE_BLENDFACTOR_SRC_COLOR) |
> +               (1u << PIPE_BLENDFACTOR_SRC_ALPHA) |
> +               (1u << PIPE_BLENDFACTOR_SRC_ALPHA_SATURATE) |
> +               (1u << PIPE_BLENDFACTOR_CONST_COLOR) |
> +               (1u << PIPE_BLENDFACTOR_CONST_ALPHA) |
> +               (1u << PIPE_BLENDFACTOR_SRC1_COLOR) |
> +               (1u << PIPE_BLENDFACTOR_SRC1_ALPHA) |
> +               (1u << PIPE_BLENDFACTOR_ZERO) |
> +               (1u << PIPE_BLENDFACTOR_INV_SRC_COLOR) |
> +               (1u << PIPE_BLENDFACTOR_INV_SRC_ALPHA) |
> +               (1u << PIPE_BLENDFACTOR_INV_CONST_COLOR) |
> +               (1u << PIPE_BLENDFACTOR_INV_CONST_ALPHA) |
> +               (1u << PIPE_BLENDFACTOR_INV_SRC1_COLOR) |
> +               (1u << PIPE_BLENDFACTOR_INV_SRC1_ALPHA);
> +
> +       if (dst == PIPE_BLENDFACTOR_ONE &&
> +           (src_allowed & (1u << src))) {
> +               /* Addition is commutative, but floating point addition isn't
> +                * associative: subtle changes can be introduced via different
> +                * rounding.
> +                *
> +                * Out-of-order is also non-deterministic, which means that
> +                * this breaks OpenGL invariance requirements. So only enable
> +                * out-of-order additive blending if explicitly allowed by a
> +                * setting.
> +                */
> +               if (func == PIPE_BLEND_MAX || func == PIPE_BLEND_MIN ||
> +                   (func == PIPE_BLEND_ADD && sscreen->commutative_blend_add))
> +                       blend->commutative_4bit |= chanmask;
> +       }
> +}
> +
>  /**
>   * Get rid of DST in the blend factors by commuting the operands:
>   *    func(src * DST, dst * 0) ---> func(src * 0, dst * SRC)
>   */
>  static void si_blend_remove_dst(unsigned *func, unsigned *src_factor,
>                                 unsigned *dst_factor, unsigned expected_dst,
>                                 unsigned replacement_src)
>  {
>         if (*src_factor == expected_dst &&
>             *dst_factor == PIPE_BLENDFACTOR_ZERO) {
> @@ -486,20 +528,25 @@ static void *si_create_blend_state_mode(struct pipe_context *ctx,
>                 /* cb_render_state will disable unused ones */
>                 blend->cb_target_mask |= (unsigned)state->rt[j].colormask << (4 * i);
>                 if (state->rt[j].colormask)
>                         blend->cb_target_enabled_4bit |= 0xf << (4 * i);
>
>                 if (!state->rt[j].colormask || !state->rt[j].blend_enable) {
>                         si_pm4_set_reg(pm4, R_028780_CB_BLEND0_CONTROL + i * 4, blend_cntl);
>                         continue;
>                 }
>
> +               si_blend_check_commutativity(sctx->screen, blend,
> +                                            eqRGB, srcRGB, dstRGB, 0x7 << (4 * i));
> +               si_blend_check_commutativity(sctx->screen, blend,
> +                                            eqA, srcA, dstA, 0x8 << (4 * i));
> +
>                 /* Blending optimizations for RB+.
>                  * These transformations don't change the behavior.
>                  *
>                  * First, get rid of DST in the blend factors:
>                  *    func(src * DST, dst * 0) ---> func(src * 0, dst * SRC)
>                  */
>                 si_blend_remove_dst(&eqRGB, &srcRGB, &dstRGB,
>                                     PIPE_BLENDFACTOR_DST_COLOR,
>                                     PIPE_BLENDFACTOR_SRC_COLOR);
>                 si_blend_remove_dst(&eqA, &srcA, &dstA,
> @@ -629,20 +676,21 @@ static void si_bind_blend_state(struct pipe_context *ctx, void *state)
>             (!old_blend ||
>              old_blend->alpha_to_coverage != blend->alpha_to_coverage ||
>              old_blend->blend_enable_4bit != blend->blend_enable_4bit ||
>              old_blend->cb_target_enabled_4bit != blend->cb_target_enabled_4bit))
>                 si_mark_atom_dirty(sctx, &sctx->dpbb_state);
>
>         if (sctx->screen->has_out_of_order_rast &&
>             (!old_blend ||
>              (old_blend->blend_enable_4bit != blend->blend_enable_4bit ||
>               old_blend->cb_target_enabled_4bit != blend->cb_target_enabled_4bit ||
> +             old_blend->commutative_4bit != blend->commutative_4bit ||
>               old_blend->logicop_enable != blend->logicop_enable)))
>                 si_mark_atom_dirty(sctx, &sctx->msaa_config);
>  }
>
>  static void si_delete_blend_state(struct pipe_context *ctx, void *state)
>  {
>         struct si_context *sctx = (struct si_context *)ctx;
>         si_pm4_delete_state(sctx, blend, (struct si_state_blend *)state);
>  }
>
> @@ -3193,26 +3241,37 @@ static bool si_out_of_order_rasterization(struct si_context *sctx)
>                         return false;
>
>                 if (sctx->b.num_perfect_occlusion_queries != 0 &&
>                     !dsa_order_invariant.pass_set)
>                         return false;
>         }
>
>         if (!colormask)
>                 return true;
>
> -       bool blend_enabled = (colormask & blend->blend_enable_4bit) != 0;
> +       unsigned blendmask = colormask & blend->blend_enable_4bit;
>
> -       if (blend_enabled)
> -               return false; /* TODO */
> +       if (blendmask) {
> +               /* Only commutative blending. */
> +               if (blendmask & ~blend->commutative_4bit)
> +                       return false;
> +
> +               if (!dsa_order_invariant.pass_set)
> +                       return false;
> +       }
> +
> +       if (colormask & ~blendmask) {
> +               if (!dsa_order_invariant.pass_last)
> +                       return false;
> +       }
>
> -       return dsa_order_invariant.pass_last;
> +       return true;
>  }
>
>  static void si_emit_msaa_config(struct si_context *sctx, struct r600_atom *atom)
>  {
>         struct radeon_winsys_cs *cs = sctx->b.gfx.cs;
>         unsigned num_tile_pipes = sctx->screen->b.info.num_tile_pipes;
>         /* 33% faster rendering to linear color buffers */
>         bool dst_is_linear = sctx->framebuffer.any_dst_linear;
>         bool out_of_order_rast = si_out_of_order_rasterization(sctx);
>         unsigned sc_mode_cntl_1 =
> diff --git a/src/gallium/drivers/radeonsi/si_state.h b/src/gallium/drivers/radeonsi/si_state.h
> index 56e597a5813..5aa50c58932 100644
> --- a/src/gallium/drivers/radeonsi/si_state.h
> +++ b/src/gallium/drivers/radeonsi/si_state.h
> @@ -48,20 +48,21 @@ struct si_shader_selector;
>
>  struct si_state_blend {
>         struct si_pm4_state     pm4;
>         uint32_t                cb_target_mask;
>         /* Set 0xf or 0x0 (4 bits) per render target if the following is
>          * true. ANDed with spi_shader_col_format.
>          */
>         unsigned                cb_target_enabled_4bit;
>         unsigned                blend_enable_4bit;
>         unsigned                need_src_alpha_4bit;
> +       unsigned                commutative_4bit;
>         bool                    alpha_to_coverage:1;
>         bool                    alpha_to_one:1;
>         bool                    dual_src_blend:1;
>         bool                    logicop_enable:1;
>  };
>
>  struct si_state_rasterizer {
>         struct si_pm4_state     pm4;
>         /* poly offset states for 16-bit, 24-bit, and 32-bit zbuffers */
>         struct si_pm4_state     *pm4_poly_offset;
> diff --git a/src/util/xmlpool/t_options.h b/src/util/xmlpool/t_options.h
> index c92215183a5..214c7c359ee 100644
> --- a/src/util/xmlpool/t_options.h
> +++ b/src/util/xmlpool/t_options.h
> @@ -436,10 +436,15 @@ DRI_CONF_OPT_END
>
>  #define DRI_CONF_RADEONSI_ENABLE_SISCHED(def) \
>  DRI_CONF_OPT_BEGIN_B(radeonsi_enable_sisched, def) \
>          DRI_CONF_DESC(en,gettext("Use the LLVM sisched option for shader compiles")) \
>  DRI_CONF_OPT_END
>
>  #define DRI_CONF_RADEONSI_ASSUME_NO_Z_FIGHTS(def) \
>  DRI_CONF_OPT_BEGIN_B(radeonsi_assume_no_z_fights, def) \
>          DRI_CONF_DESC(en,gettext("Assume no Z fights (enables aggressive out-of-order rasterization to improve performance; may cause rendering errors)")) \
>  DRI_CONF_OPT_END
> +
> +#define DRI_CONF_RADEONSI_COMMUTATIVE_BLEND_ADD(def) \
> +DRI_CONF_OPT_BEGIN_B(radeonsi_commutative_blend_add, def) \
> +        DRI_CONF_DESC(en,gettext("Commutative additive blending optimizations (may cause rendering errors)")) \
> +DRI_CONF_OPT_END
> --
> 2.11.0
>
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