Module: Mesa Branch: master Commit: 4b244dc64f439da11bba7224db836b376e2ca75a URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=4b244dc64f439da11bba7224db836b376e2ca75a
Author: Iago Toral Quiroga <ito...@igalia.com> Date: Thu Apr 8 09:02:16 2021 +0200 broadcom/compiler: add a definition for the unifa skip distance We will be using this distance to setup another optimization in a follow-up patch. Reviewed-by: Alejandro Piñeiro <apinhe...@igalia.com> x# Please enter the commit message for your changes. Lines starting Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10100> --- src/broadcom/compiler/nir_to_vir.c | 13 +++++++++++-- src/broadcom/compiler/v3d_compiler.h | 7 +++++++ 2 files changed, 18 insertions(+), 2 deletions(-) diff --git a/src/broadcom/compiler/nir_to_vir.c b/src/broadcom/compiler/nir_to_vir.c index 2fbc81c4535..fbfb57489da 100644 --- a/src/broadcom/compiler/nir_to_vir.c +++ b/src/broadcom/compiler/nir_to_vir.c @@ -2644,6 +2644,12 @@ emit_ldunifa(struct v3d_compile *c, struct qreg *result) static void ntq_emit_load_ubo_unifa(struct v3d_compile *c, nir_intrinsic_instr *instr) { + /* Every ldunifa auto-increments the unifa address by 4 bytes, so our + * last unifa offset is 4 bytes ahead of the offset of the last load. + */ + static const int32_t max_unifa_skip_dist = + MAX_UNIFA_SKIP_DISTANCE - 4; + bool dynamic_src = !nir_src_is_const(instr->src[1]); uint32_t const_offset = dynamic_src ? 0 : nir_src_as_uint(instr->src[1]); @@ -2656,7 +2662,10 @@ ntq_emit_load_ubo_unifa(struct v3d_compile *c, nir_intrinsic_instr *instr) index++; /* We can only keep track of the last unifa address we used with - * constant offset loads. + * constant offset loads. If the new load targets the same UBO and + * is close enough to the previous load, we can skip the unifa register + * write by emitting dummy ldunifa instructions to update the unifa + * address. */ bool skip_unifa = false; uint32_t ldunifa_skips = 0; @@ -2665,7 +2674,7 @@ ntq_emit_load_ubo_unifa(struct v3d_compile *c, nir_intrinsic_instr *instr) } else if (c->cur_block == c->last_unifa_block && c->last_unifa_index == index && c->last_unifa_offset <= const_offset && - c->last_unifa_offset + 12 >= const_offset) { + c->last_unifa_offset + max_unifa_skip_dist >= const_offset) { skip_unifa = true; ldunifa_skips = (const_offset - c->last_unifa_offset) / 4; } else { diff --git a/src/broadcom/compiler/v3d_compiler.h b/src/broadcom/compiler/v3d_compiler.h index a741c1785ec..40447e5b44e 100644 --- a/src/broadcom/compiler/v3d_compiler.h +++ b/src/broadcom/compiler/v3d_compiler.h @@ -61,6 +61,13 @@ */ #define MAX_TMU_QUEUE_SIZE 8 +/** + * Maximum offset distance in bytes between two consecutive constant UBO loads + * for the same UBO where we would favor updating the unifa address by emitting + * dummy ldunifa instructions to avoid writing the unifa register. + */ +#define MAX_UNIFA_SKIP_DISTANCE 16 + struct nir_builder; struct v3d_fs_inputs { _______________________________________________ mesa-commit mailing list mesa-commit@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-commit
