buffer_cache: Heuristically detect stream buffers

Detect when a memory region has been joined several times and increase
the size of the created buffer on those instances. The buffer is assumed
to be a "stream buffer", increasing its size should stop us from
constantly recreating it and fragmenting memory.
This commit is contained in:
ReinUsesLisp 2021-01-18 17:14:14 -03:00
parent ec9354d6d9
commit 2b95c137ff
2 changed files with 33 additions and 6 deletions

View File

@ -251,6 +251,16 @@ public:
flags &= ~BufferFlagBits::Picked;
}
/// Increases the likeliness of this being a stream buffer
void IncreaseStreamScore(int score) noexcept {
stream_score += score;
}
/// Returns the likeliness of this being a stream buffer
[[nodiscard]] int StreamScore() const noexcept {
return stream_score;
}
/// Returns true when vaddr -> vaddr+size is fully contained in the buffer
[[nodiscard]] bool IsInBounds(VAddr addr, u64 size) const noexcept {
return addr >= cpu_addr && addr + size <= cpu_addr + SizeBytes();
@ -574,6 +584,7 @@ private:
VAddr cpu_addr = 0;
Words words;
BufferFlagBits flags{};
int stream_score = 0;
};
} // namespace VideoCommon

View File

@ -75,6 +75,7 @@ class BufferCache {
std::vector<BufferId> ids;
VAddr begin;
VAddr end;
bool has_stream_leap = false;
};
struct Binding {
@ -228,7 +229,7 @@ private:
[[nodiscard]] OverlapResult ResolveOverlaps(VAddr cpu_addr, u32 wanted_size);
void JoinOverlap(BufferId new_buffer_id, BufferId overlap_id);
void JoinOverlap(BufferId new_buffer_id, BufferId overlap_id, bool accumulate_stream_score);
[[nodiscard]] BufferId CreateBuffer(VAddr cpu_addr, u32 wanted_size);
@ -670,7 +671,7 @@ void BufferCache<P>::BindHostGraphicsUniformBuffer(size_t stage, u32 index, u32
const VAddr cpu_addr = binding.cpu_addr;
const u32 size = binding.size;
Buffer& buffer = slot_buffers[binding.buffer_id];
if (size <= SKIP_CACHE_SIZE && !buffer.IsRegionGpuModified(cpu_addr, size)) {
if (size <= runtime.SkipCacheSize() && !buffer.IsRegionGpuModified(cpu_addr, size)) {
if constexpr (IS_OPENGL) {
if (runtime.HasFastBufferSubData()) {
// Fast path for Nvidia
@ -1000,9 +1001,12 @@ BufferId BufferCache<P>::FindBuffer(VAddr cpu_addr, u32 size) {
template <class P>
typename BufferCache<P>::OverlapResult BufferCache<P>::ResolveOverlaps(VAddr cpu_addr,
u32 wanted_size) {
static constexpr int STREAM_LEAP_THRESHOLD = 16;
std::vector<BufferId> overlap_ids;
VAddr begin = cpu_addr;
VAddr end = cpu_addr + wanted_size;
int stream_score = 0;
bool has_stream_leap = false;
for (; cpu_addr >> PAGE_BITS < Common::DivCeil(end, PAGE_SIZE); cpu_addr += PAGE_SIZE) {
const BufferId overlap_id = page_table[cpu_addr >> PAGE_BITS];
if (!overlap_id) {
@ -1012,26 +1016,38 @@ typename BufferCache<P>::OverlapResult BufferCache<P>::ResolveOverlaps(VAddr cpu
if (overlap.IsPicked()) {
continue;
}
overlap.Pick();
overlap_ids.push_back(overlap_id);
overlap.Pick();
const VAddr overlap_cpu_addr = overlap.CpuAddr();
if (overlap_cpu_addr < begin) {
cpu_addr = begin = overlap_cpu_addr;
}
end = std::max(end, overlap_cpu_addr + overlap.SizeBytes());
stream_score += overlap.StreamScore();
if (stream_score > STREAM_LEAP_THRESHOLD && !has_stream_leap) {
// When this memory region has been joined a bunch of times, we assume it's being used
// as a stream buffer. Increase the size to skip constantly recreating buffers.
has_stream_leap = true;
end += PAGE_SIZE * 256;
}
}
return OverlapResult{
.ids = std::move(overlap_ids),
.begin = begin,
.end = end,
.has_stream_leap = has_stream_leap,
};
}
template <class P>
void BufferCache<P>::JoinOverlap(BufferId new_buffer_id, BufferId overlap_id) {
void BufferCache<P>::JoinOverlap(BufferId new_buffer_id, BufferId overlap_id,
bool accumulate_stream_score) {
Buffer& new_buffer = slot_buffers[new_buffer_id];
Buffer& overlap = slot_buffers[overlap_id];
if (accumulate_stream_score) {
new_buffer.IncreaseStreamScore(overlap.StreamScore() + 1);
}
std::vector<BufferCopy> copies;
const size_t dst_base_offset = overlap.CpuAddr() - new_buffer.CpuAddr();
overlap.ForEachDownloadRange([&](u64 begin, u64 range_size) {
@ -1056,7 +1072,7 @@ BufferId BufferCache<P>::CreateBuffer(VAddr cpu_addr, u32 wanted_size) {
const u32 size = static_cast<u32>(overlap.end - overlap.begin);
const BufferId new_buffer_id = slot_buffers.insert(runtime, rasterizer, overlap.begin, size);
for (const BufferId overlap_id : overlap.ids) {
JoinOverlap(new_buffer_id, overlap_id);
JoinOverlap(new_buffer_id, overlap_id, !overlap.has_stream_leap);
}
Register(new_buffer_id);
return new_buffer_id;