texture_cache: collect from 5 GiB of device memory on every GPU

The collector's thresholds follow the card's size and budget (critical
at budget - 768 MiB), so the cache keeps textures of earlier scenes
until the card is nearly full: Mario Kart World used 6.7 GB of an 8 GB
card, and more on larger cards. Cap the critical threshold at 5 GiB (and
expected/minimum below it) whatever the card. Same build, back to back:
peak device memory 6.7 -> 5.6 GB, frames over 100 ms 114 -> 64 in six
minutes, average frame time unchanged. The EDEN_NX2_TC_*_MIB overrides
still apply.

2 files changed, 11 insertions, 0 deletions

diff --git a/src/video_core/texture_cache/texture_cache.h b/src/video_core/texture_cache/texture_cache.h
index 63abffed0f..bd5f7debfb 100644
--- a/src/video_core/texture_cache/texture_cache.h
+++ b/src/video_core/texture_cache/texture_cache.h
@@ -185,6 +185,14 @@ void TextureCache<P>::RunGarbageCollector() {
 
 template <class P>
 void TextureCache<P>::ApplyThresholdOverrides(bool log) {
+    // On every GPU: past what a frame needs, more device memory only keeps the textures of earlier
+    // scenes (title 1 filled 6.7 GB of an 8 GB card and draws its races in ~5 GB), so collect from
+    // MaxCriticalMemory on rather than near the card's budget.
+    critical_memory = (std::min)(critical_memory, MaxCriticalMemory);
+    expected_memory =
+        (std::min)(expected_memory, critical_memory - (std::min)(critical_memory, u64{768_MiB}));
+    minimum_memory =
+        (std::min)(minimum_memory, expected_memory - (std::min)(expected_memory, u64{1_GiB}));
     // EDEN_NX2_TC_EXPECTED_MIB / EDEN_NX2_TC_CRITICAL_MIB override the collector's thresholds.
     for (const auto& [name, target] : {std::pair{"EDEN_NX2_TC_EXPECTED_MIB", &expected_memory},
                                        std::pair{"EDEN_NX2_TC_CRITICAL_MIB", &critical_memory}}) {
diff --git a/src/video_core/texture_cache/texture_cache_base.h b/src/video_core/texture_cache/texture_cache_base.h
index 11e95f98b3..660203f172 100644
--- a/src/video_core/texture_cache/texture_cache_base.h
+++ b/src/video_core/texture_cache/texture_cache_base.h
@@ -144,6 +144,9 @@ class TextureCache : public VideoCommon::ChannelSetupCaches<TextureCacheChannelI
 
     static constexpr s64 DEFAULT_EXPECTED_MEMORY = 1_GiB + 125_MiB;
     static constexpr s64 DEFAULT_CRITICAL_MEMORY = 1_GiB + 625_MiB;
+    /// The most device memory the collector lets the cache fill before it collects in earnest,
+    /// on every GPU (ApplyThresholdOverrides).
+    static constexpr u64 MaxCriticalMemory = 5_GiB;
     static constexpr size_t GC_EMERGENCY_COUNTS = 2;
 
     using Runtime = typename P::Runtime;