From a667551cdf6e9044e43e1d0c37320c3ec82a1213 Mon Sep 17 00:00:00 2001 From: Duck <350528965+Duck912@users.noreply.github.com> Date: Tue, 3 Nov 2026 02:47:54 -0500 Subject: video_core: cut per-draw work on the GPU back thread in crowded scenes (#374) * video_core: demote the texture cache's per-draw debug logs to trace The invalid sampler and image view index messages fire for unused binding slots on every draw. Filtered LOG_DEBUG messages still cost a call and argument packing: in a Fire Emblem: Fortune's Weave city scene (about 2,100 draws per frame) they were 3.1% of the GPUBack thread's samples. LOG_TRACE compiles them out of release builds. Assisted-by: Claude Opus 5.5 (profiling, porting and drafting) Signed-off-by: Duck912 <350528965+Duck912@users.noreply.github.com> * texture_cache: read a descriptor with one page lookup DescriptorTable::Read runs for every texture and sampler of every draw, and it read each 32-byte TIC/TSC entry through the generic ReadBlockUnsafe page walk. In a Fire Emblem: Fortune's Weave city scene (about 2,100 draws per frame) that was 5.0% of the GPUBack thread's samples. An entry within one page is contiguous in host memory, so it is now a single page lookup and memcpy. Entries that cross a page and pages without host memory still take the block read, so unmapped and unbacked entries still read as zero. The same change in another Eden-based build cut these reads from 6.4% to 0.4% of its GPU thread. Assisted-by: Claude Opus 5.5 (profiling, porting and drafting) Signed-off-by: Duck912 <350528965+Duck912@users.noreply.github.com> --------- Signed-off-by: Duck912 <350528965+Duck912@users.noreply.github.com> --- src/video_core/texture_cache/descriptor_table.h | 12 +++++++++++- src/video_core/texture_cache/texture_cache.h | 4 ++-- 2 files changed, 13 insertions(+), 3 deletions(-) diff --git a/src/video_core/texture_cache/descriptor_table.h b/src/video_core/texture_cache/descriptor_table.h index a441e572de..2c768b72fc 100644 --- a/src/video_core/texture_cache/descriptor_table.h +++ b/src/video_core/texture_cache/descriptor_table.h @@ -7,12 +7,14 @@ #pragma once #include +#include #include #include "common/alignment.h" #include "common/common_types.h" #include "common/div_ceil.h" #include "common/assert.h" +#include "core/memory.h" #include "video_core/memory_manager.h" #include "video_core/rasterizer_interface.h" @@ -44,7 +46,15 @@ public: } const GPUVAddr gpu_addr = current_gpu_addr + index * sizeof(T); std::pair result; - gpu_memory.ReadBlockUnsafe(gpu_addr, std::addressof(result.first), sizeof(T)); + // This runs for every texture and sampler of every draw. An entry within one page is + // contiguous in host memory, so a single page lookup replaces the generic block read. + const bool one_page = + (gpu_addr & Core::Memory::YUZU_PAGEMASK) + sizeof(T) <= Core::Memory::YUZU_PAGESIZE; + if (const u8* const host = one_page ? gpu_memory.GetPointer(gpu_addr) : nullptr) { + std::memcpy(std::addressof(result.first), host, sizeof(T)); + } else { + gpu_memory.ReadBlockUnsafe(gpu_addr, std::addressof(result.first), sizeof(T)); + } if ((read_descriptors[index / 64] & (1ULL << (index % 64))) != 0) { result.second = result.first != descriptors[index]; } else { diff --git a/src/video_core/texture_cache/texture_cache.h b/src/video_core/texture_cache/texture_cache.h index abb22b9bfb..ea82ab02e7 100644 --- a/src/video_core/texture_cache/texture_cache.h +++ b/src/video_core/texture_cache/texture_cache.h @@ -580,7 +580,7 @@ template SamplerId TextureCache

::GetSamplerId(u32 index, bool compute) { auto& table = compute ? channel_state->compute_sampler_table : channel_state->graphics_sampler_table; if (index > table.current_limit) { - LOG_DEBUG(HW_GPU, "Invalid sampler index={}", index); + LOG_TRACE(HW_GPU, "Invalid sampler index={}", index); return NULL_SAMPLER_ID; } auto const map_index = index | (compute ? Common::SlotId::TAGGED_VALUE : 0); @@ -812,7 +812,7 @@ ImageViewId TextureCache

::VisitImageView(u32 index, bool compute) { index = Tegra::Texture::TextureHeaderIndex(index, table.current_limit, gpu_memory->UsesNativeTiling()); if (index > table.current_limit) { - LOG_DEBUG(HW_GPU, "Invalid image view index={}", index); + LOG_TRACE(HW_GPU, "Invalid image view index={}", index); return NULL_IMAGE_VIEW_ID; } auto const map_index = index | (compute ? Common::SlotId::TAGGED_VALUE : 0); -- cgit v1.2.3