On Wed, Jan 24, 2018 at 12:29:05PM -0800, Jason Ekstrand wrote:
> On Wed, Jan 24, 2018 at 6:15 AM, Pohjolainen, Topi <
> [email protected]> wrote:
>
> > On Fri, Jan 19, 2018 at 03:47:31PM -0800, Jason Ekstrand wrote:
> > > This pass performs an "ambiguate" operation on a CCS-compressed surface
> > > by manually writing zeros into the CCS. On gen8+, ISL gives us a fairly
> > > detailed notion of how the CCS is laid out so this is fairly simple to
> > > do. On gen7, the CCS tiling is quite crazy but that isn't an issue
> > > because we can only do CCS on single-slice images so we can just blast
> > > over the entire CCS buffer if we want to.
> > > ---
> > > src/intel/blorp/blorp.h | 5 ++
> > > src/intel/blorp/blorp_clear.c | 149 ++++++++++++++++++++++++++++++
> > ++++++++++++
> > > 2 files changed, 154 insertions(+)
> > >
> > > diff --git a/src/intel/blorp/blorp.h b/src/intel/blorp/blorp.h
> > > index a1dd571..478a9af 100644
> > > --- a/src/intel/blorp/blorp.h
> > > +++ b/src/intel/blorp/blorp.h
> > > @@ -204,6 +204,11 @@ blorp_ccs_resolve(struct blorp_batch *batch,
> > > enum blorp_fast_clear_op resolve_op);
> > >
> > > void
> > > +blorp_ccs_ambiguate(struct blorp_batch *batch,
> > > + struct blorp_surf *surf,
> > > + uint32_t level, uint32_t layer);
> > > +
> > > +void
> > > blorp_mcs_partial_resolve(struct blorp_batch *batch,
> > > struct blorp_surf *surf,
> > > enum isl_format format,
> > > diff --git a/src/intel/blorp/blorp_clear.c
> > b/src/intel/blorp/blorp_clear.c
> > > index 8e7bc9f..fa2abd9 100644
> > > --- a/src/intel/blorp/blorp_clear.c
> > > +++ b/src/intel/blorp/blorp_clear.c
> > > @@ -881,3 +881,152 @@ blorp_mcs_partial_resolve(struct blorp_batch
> > *batch,
> > >
> > > batch->blorp->exec(batch, ¶ms);
> > > }
> > > +
> > > +/** Clear a CCS to the "uncompressed" state
> > > + *
> > > + * This pass is the CCS equivalent of a "HiZ resolve". It sets the CCS
> > values
> > > + * for a given layer/level of a surface to 0x0 which is the
> > "uncompressed"
> > > + * state which tells the sampler to go look at the main surface.
> > > + */
> > > +void
> > > +blorp_ccs_ambiguate(struct blorp_batch *batch,
> > > + struct blorp_surf *surf,
> > > + uint32_t level, uint32_t layer)
> > > +{
> > > + struct blorp_params params;
> > > + blorp_params_init(¶ms);
> > > +
> > > + assert(ISL_DEV_GEN(batch->blorp->isl_dev) >= 7);
> > > +
> > > + const struct isl_format_layout *aux_fmtl =
> > > + isl_format_get_layout(surf->aux_surf->format);
> > > + assert(aux_fmtl->txc == ISL_TXC_CCS);
> > > +
> > > + params.dst = (struct brw_blorp_surface_info) {
> > > + .enabled = true,
> > > + .addr = surf->aux_addr,
> > > + .view = {
> > > + .usage = ISL_SURF_USAGE_RENDER_TARGET_BIT,
> > > + .format = ISL_FORMAT_R32G32B32A32_UINT,
> > > + .base_level = 0,
> > > + .base_array_layer = 0,
> > > + .levels = 1,
> > > + .array_len = 1,
> > > + .swizzle = ISL_SWIZZLE_IDENTITY,
> > > + },
> > > + };
> > > +
> > > + uint32_t z = 0;
> > > + if (surf->surf->dim == ISL_SURF_DIM_3D) {
> > > + z = layer;
> > > + layer = 0;
> > > + }
> > > +
> > > + uint32_t offset_B, x_offset_el, y_offset_el;
> > > + isl_surf_get_image_offset_el(surf->aux_surf, level, layer, z,
> > > + &x_offset_el, &y_offset_el);
> > > + isl_tiling_get_intratile_offset_el(surf->aux_surf->tiling,
> > aux_fmtl->bpb,
> > > + surf->aux_surf->row_pitch,
> > > + x_offset_el, y_offset_el,
> > > + &offset_B, &x_offset_el,
> > &y_offset_el);
> > > + params.dst.addr.offset += offset_B;
> > > +
> > > + const uint32_t width_px = minify(surf->surf->logical_level0_px.width,
> > level);
> > > + const uint32_t height_px =
> > > minify(surf->surf->logical_level0_px.height,
> > level);
> > > + const uint32_t width_el = DIV_ROUND_UP(width_px, aux_fmtl->bw);
> > > + const uint32_t height_el = DIV_ROUND_UP(height_px, aux_fmtl->bh);
I need to think about these numbers a little more. I think I got the other
sources of my confusion figured out further down. See further down.
> > > +
> > > + struct isl_tile_info ccs_tile_info;
> > > + isl_surf_get_tile_info(surf->aux_surf, &ccs_tile_info);
> > > +
> > > + /* We're going to map it as a regular RGBA32_UINT surface. We need
> > to
> > > + * downscale a good deal. We start by computing the area on the CCS
> > to
> > > + * clear in units of Y-tiled cache lines.
> > > + */
> > > + uint32_t x_offset_y_cl, y_offset_y_cl, width_y_cl, height_y_cl;
> > > + if (ISL_DEV_GEN(batch->blorp->isl_dev) >= 8) {
> > > + /* From the Sky Lake PRM Vol. 12 in the section on planes:
> > > + *
> > > + * "The Color Control Surface (CCS) contains the compression
> > status
> > > + * of the cache-line pairs. The compression state of the
> > cache-line
> > > + * pair is specified by 2 bits in the CCS. Each CCS cache-line
> > > + * represents an area on the main surface of 16x16 sets of 128
> > byte
> > > + * Y-tiled cache-line-pairs. CCS is always Y tiled."
> > > + *
> > > + * Each 2-bit surface element in the CCS corresponds to a single
> > > + * cache-line pair in the main surface. This means that 16x16 el
> > block
> > > + * in the CCS maps to a Y-tiled cache line. Fortunately, CCS
> > layouts
> > > + * are calculated with a very large alignment so we can round up
> > to a
> > > + * whole cache line without worrying about overdraw.
> > > + */
> > > +
> > > + /* On Broadwell and above, a CCS tile is the same as a Y tile when
> > > + * viewed at the cache-line granularity. Fortunately, the
> > horizontal
> > > + * and vertical alignment requirements of the CCS are such that
> > we can
> > > + * align to an entire cache line without worrying about crossing
> > over
> > > + * from one LOD to another.
> > > + */
> > > + const uint32_t scale_x = ccs_tile_info.logical_extent_el.w / 8;
> > > + const uint32_t scale_y = ccs_tile_info.logical_extent_el.h / 8;
> >
> > These are now CCS tile dimensions in number of bytes, right?
> >
>
> No. They are the number of 2-bit CCS elements in a single CCS cache line.
Okay, thanks. I went to read isl_tiling_get_info() and "case ISL_TILING_CCS".
There the sentence "The CCS being Y-tiled implies that it's an 8x8 grid of
cache-lines" helped me quite a bit.
>
>
> > > + assert(surf->aux_surf->image_alignment_el.w % scale_x == 0);
> > > + assert(surf->aux_surf->image_alignment_el.h % scale_y == 0);
> > > +
> > > + assert(x_offset_el % scale_x == 0 && y_offset_el % scale_y == 0);
> > > + x_offset_y_cl = x_offset_el / scale_x;
> > > + y_offset_y_cl = y_offset_el / scale_y;
> > > + width_y_cl = DIV_ROUND_UP(width_el, scale_x);
> > > + height_y_cl = DIV_ROUND_UP(height_el, scale_y);
> >
> > This talks about cache lines but I'm reading that these *_cl are actually
> > numbers in CCS tiles. What am I missing/misunderstanding?
> >
>
> They are in terms of CCS cache lines. Maybe the "y_cl" is misleading and
> "ccs_cl" would be better?
You do document above that "CCS tile is the same as a Y tile when viewed at
the cache-line granularity" so I think it is fine.
>
>
> > > + } else {
> > > + /* On gen7, the CCS tiling is not so nice. However, there we are
> > > + * guaranteed that we only have a single level and slice so we
> > don't
> > > + * have to worry about it and can just align to a whole tile.
> > > + */
> > > + assert(x_offset_el == 0 && y_offset_el == 0);
> > > + const uint32_t width_tl =
> > > + DIV_ROUND_UP(width_el, ccs_tile_info.logical_extent_el.w);
> > > + const uint32_t height_tl =
> > > + DIV_ROUND_UP(height_el, ccs_tile_info.logical_extent_el.h);
> > > + x_offset_y_cl = 0;
> > > + y_offset_y_cl = 0;
> > > + width_y_cl = width_tl * 8;
> > > + height_y_cl = height_tl * 8;
> >
> > I am probably badly off in the weeds, and just need to ask. Here I'm
> > thinking
> > that width_tl, for example, is something in number of bits and width_tl
> > becomes width in CCS tiles.
> >
>
> width_tl is width in CCS tiles. width_y_cl is width in cache lines.
>
>
> > > + }
> > > +
> > > + /* We're going to use a RGBA32 format so as to write data as quickly
> > as
> > > + * possible. A y-tiled cache line will then be 1x4 px.
> > > + */
> > > + const uint32_t x_offset_rgba_px = x_offset_y_cl;
> > > + const uint32_t y_offset_rgba_px = y_offset_y_cl * 4;
> > > + const uint32_t width_rgba_px = width_y_cl;
> > > + const uint32_t height_rgba_px = height_y_cl * 4;
> >
> > And my confusion continues here. Numbers denoted as *_cl represent
> > something
> > four times as small as pixels. I'd thought one would need to divide the
> > number
> > instead of multiplying it. One is about to represent the same amount with
> > larger units (pixels).
> >
> > > +
> > > + MAYBE_UNUSED bool ok =
> > > + isl_surf_init(batch->blorp->isl_dev, ¶ms.dst.surf,
> > > + .dim = ISL_SURF_DIM_2D,
> > > + .format = ISL_FORMAT_R32G32B32A32_UINT,
> > > + .width = width_rgba_px + x_offset_rgba_px,
> > > + .height = height_rgba_px + y_offset_rgba_px,
> > > + .depth = 1,
> > > + .levels = 1,
> > > + .array_len = 1,
> > > + .samples = 1,
> > > + .row_pitch = surf->aux_surf->row_pitch,
> > > + .usage = ISL_SURF_USAGE_RENDER_TARGET_BIT,
> > > + .tiling_flags = ISL_TILING_Y0_BIT);
> > > + assert(ok);
> > > + assert(offset_B + params.dst.surf.size <= surf->aux_surf->size);
> > > +
> > > + params.x0 = x_offset_rgba_px;
> > > + params.y0 = y_offset_rgba_px;
> > > + params.x1 = x_offset_rgba_px + width_rgba_px;
> > > + params.y1 = y_offset_rgba_px + height_rgba_px;
> > > +
> > > + /* A CCS value of 0 means "uncompressed." */
> > > + memset(¶ms.wm_inputs.clear_color, 0,
> > > + sizeof(params.wm_inputs.clear_color));
> > > +
> > > + if (!blorp_params_get_clear_kernel(batch->blorp, ¶ms, true))
> > > + return;
> > > +
> > > + batch->blorp->exec(batch, ¶ms);
> > > +}
> > > --
> > > 2.5.0.400.gff86faf
> > >
> > > _______________________________________________
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> >
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