On Fri, Aug 3, 2018 at 5:57 PM, Rhys Perry <pendingchao...@gmail.com> wrote:
> Previously, UBOs were implemented using global memory loads for compute on
> Kepler+ because it only supported 8 constant buffers on compute. This
> required bounds checking and expensive load instructions.
>
> However 6 of the constant buffer bindings were left unused, this uses them
> instead of loading from global memory in the shader for the first 6
> non-user constant buffers when possible.
>
> total instructions in shared programs : 5787979 -> 5748677 (-0.68%)
> total gprs used in shared programs : 669901 -> 669373 (-0.08%)
> total shared used in shared programs : 548832 -> 548832 (0.00%)
> total local used in shared programs : 21068 -> 21064 (-0.02%)
>
> local shared gpr inst bytes
> helped 1 0 152 274 274
> hurt 0 0 0 0 0
>
> Signed-off-by: Rhys Perry <pendingchao...@gmail.com>
> ---
> .../nouveau/codegen/nv50_ir_lowering_nvc0.cpp | 18 +++++++-------
> src/gallium/drivers/nouveau/nvc0/nve4_compute.c | 28
> ++++++++++++++++++++++
> 2 files changed, 36 insertions(+), 10 deletions(-)
>
> diff --git a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> index 1410cf26c8..0fba96f261 100644
> --- a/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> +++ b/src/gallium/drivers/nouveau/codegen/nv50_ir_lowering_nvc0.cpp
> @@ -2437,18 +2437,16 @@ NVC0LoweringPass::handleLDST(Instruction *i)
> assert(prog->getType() != Program::TYPE_FRAGMENT); // INTERP
> }
> } else if (i->src(0).getFile() == FILE_MEMORY_CONST) {
> + int8_t fileIndex = i->getSrc(0)->reg.fileIndex - 1;
> + Value *ind = i->getIndirect(0, 1);
> +
> if (targ->getChipset() >= NVISA_GK104_CHIPSET &&
> - prog->getType() == Program::TYPE_COMPUTE) {
> + prog->getType() == Program::TYPE_COMPUTE &&
> + (fileIndex >= 6 || ind)) {
> // The launch descriptor only allows to set up 8 CBs, but OpenGL
> - // requires at least 12 UBOs. To bypass this limitation, we store
> the
> - // addrs into the driver constbuf and we directly load from the
> global
> - // memory.
> - int8_t fileIndex = i->getSrc(0)->reg.fileIndex - 1;
> - Value *ind = i->getIndirect(0, 1);
> -
> - if (!ind && fileIndex == -1)
> - return;
> -
> + // requires at least 12 UBOs. To bypass this limitation, for
> constant
> + // buffers 7+, we store the addrs into the driver constbuf and we
> + // directly load from the global memory.
> if (ind) {
> // Clamp the UBO index when an indirect access is used to avoid
> // loading information from the wrong place in the driver cb.
> diff --git a/src/gallium/drivers/nouveau/nvc0/nve4_compute.c
> b/src/gallium/drivers/nouveau/nvc0/nve4_compute.c
> index 28460f8cbe..8aa8d4936f 100644
> --- a/src/gallium/drivers/nouveau/nvc0/nve4_compute.c
> +++ b/src/gallium/drivers/nouveau/nvc0/nve4_compute.c
> @@ -551,6 +551,30 @@ nve4_compute_derive_cache_split(struct nvc0_context
> *nvc0, uint32_t shared_size)
> return NVC1_3D_CACHE_SPLIT_16K_SHARED_48K_L1;
> }
>
> +static void
> +nve4_compute_setup_buf_cb(struct nvc0_context *nvc0, bool gp100, void *desc)
> +{
> + // only user constant buffers 1-6 can be put in the descriptor, the rest
> are
> + // loaded through global memory
> + for (int i = 1; i <= 6; i++) {
> + if (nvc0->constbuf[5][i].user || !nvc0->constbuf[5][i].u.buf)
> + continue;
> +
> + struct nv04_resource *res =
> + nv04_resource(nvc0->constbuf[5][i].u.buf);
> +
> + uint32_t base = res->offset + nvc0->constbuf[5][i].offset;
No compiler error on this one? Ouch. This obviously needs to be a uint64_t.
> + uint32_t size = nvc0->constbuf[5][i].size;
> + if (gp100)
> + gp100_cp_launch_desc_set_cb(desc, i, res->bo, base, size);
> + else
> + nve4_cp_launch_desc_set_cb(desc, i, res->bo, base, size);
> + }
> +
> + // there is no need to do FLUSH(NVE4_COMPUTE_FLUSH_CB) because
> + // nve4_compute_upload_input() does it later
> +}
> +
> static void
> nve4_compute_setup_launch_desc(struct nvc0_context *nvc0,
> struct nve4_cp_launch_desc *desc,
> @@ -588,6 +612,8 @@ nve4_compute_setup_launch_desc(struct nvc0_context *nvc0,
> }
> nve4_cp_launch_desc_set_cb(desc, 7, screen->uniform_bo,
> NVC0_CB_AUX_INFO(5), 1 << 11);
> +
> + nve4_compute_setup_buf_cb(nvc0, false, desc);
> }
>
> static void
> @@ -626,6 +652,8 @@ gp100_compute_setup_launch_desc(struct nvc0_context *nvc0,
> }
> gp100_cp_launch_desc_set_cb(desc, 7, screen->uniform_bo,
> NVC0_CB_AUX_INFO(5), 1 << 11);
> +
> + nve4_compute_setup_buf_cb(nvc0, true, desc);
> }
>
> static inline void *
> --
> 2.14.4
>
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