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CDVD: Add minimum buffer size to ThreadedFileReader
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If buffers are smaller than the threshold PCSX2 uses to decide whether to time a read as a seek, ThreadedFileReader fails to provide data in time for the very small linear read time cutoff
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@TellowKrinkle
TellowKrinkle committed May 3, 2021
1 parent 3d18f80 commit d949862
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Showing 2 changed files with 69 additions and 70 deletions.
132 changes: 66 additions & 66 deletions pcsx2/CDVD/ThreadedFileReader.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -16,6 +16,10 @@
#include "PrecompiledHeader.h"
#include "ThreadedFileReader.h"

// Make sure buffer size is bigger than the cutoff where PCSX2 emulates a seek
// If buffers are smaller than that, we can't keep up with linear reads
static constexpr u32 MINIMUM_SIZE = 128 * 1024;

ThreadedFileReader::ThreadedFileReader()
{
m_readThread = std::thread([](ThreadedFileReader* r){ r->Loop(); }, this);
Expand Down Expand Up @@ -86,13 +90,33 @@ void ThreadedFileReader::Loop()
if (ok)
{
// Readahead
Chunk blk = ChunkForOffset(requestOffset + requestSize);
if (blk.chunkID >= 0)
Chunk chunk = ChunkForOffset(requestOffset + requestSize);
if (chunk.chunkID >= 0)
{
(void)GetBlockPtr(blk, true);
blk = ChunkForOffset(blk.offset + blk.length);
if (blk.chunkID >= 0)
(void)GetBlockPtr(blk, true);
int buffersFilled = 0;
Buffer* buf = GetBlockPtr(chunk);
// Cancel readahead if a new request comes in
while (buf && !m_requestPtr.load(std::memory_order_acquire))
{
u32 bufsize = buf->size.load(std::memory_order_relaxed);
chunk = ChunkForOffset(buf->offset + bufsize);
if (chunk.chunkID < 0)
break;
if (buf->offset + bufsize != chunk.offset || chunk.length + bufsize > buf->cap)
{
buffersFilled++;
if (buffersFilled >= 2)
break;
buf = GetBlockPtr(chunk);
}
else
{
int amt = ReadChunk(static_cast<char*>(buf->ptr) + bufsize, chunk.chunkID);
if (amt <= 0)
break;
buf->size.store(bufsize + amt, std::memory_order_release);
}
}
}
}

Expand All @@ -108,11 +132,13 @@ void ThreadedFileReader::Loop()
}
}

ThreadedFileReader::Buffer* ThreadedFileReader::GetBlockPtr(const Chunk& block, bool isReadahead)
ThreadedFileReader::Buffer* ThreadedFileReader::GetBlockPtr(const Chunk& block)
{
for (int i = 0; i < static_cast<int>(ArraySize(m_buffer)); i++)
{
if (m_buffer[i].valid.load(std::memory_order_acquire) && m_buffer[i].offset == block.offset)
u32 size = m_buffer[i].size.load(std::memory_order_relaxed);
u64 offset = m_buffer[i].offset;
if (size && offset <= block.offset && offset + size >= block.offset + block.length)
{
m_nextBuffer = (i + 1) % ArraySize(m_buffer);
return m_buffer + i;
Expand All @@ -127,17 +153,19 @@ ThreadedFileReader::Buffer* ThreadedFileReader::GetBlockPtr(const Chunk& block,
std::unique_lock<std::mutex> lock(m_mtx, std::defer_lock);
if (std::this_thread::get_id() == m_readThread.get_id())
lock.lock();
if (buf.size < block.length)
buf.ptr = realloc(buf.ptr, block.length);
buf.valid.store(false, std::memory_order_relaxed);

u32 size = std::max(block.length, MINIMUM_SIZE);
if (buf.cap < size)
{
buf.ptr = realloc(buf.ptr, size);
buf.cap = size;
}
buf.size.store(0, std::memory_order_relaxed);
}
int size = ReadChunk(buf.ptr, block.chunkID);
if (size > 0)
{
buf.offset = block.offset;
buf.size = size;
buf.valid.store(true, std::memory_order_release);
buf.size.store(size, std::memory_order_release);
m_nextBuffer = (m_nextBuffer + 1) % ArraySize(m_buffer);
return &buf;
}
Expand All @@ -146,63 +174,34 @@ ThreadedFileReader::Buffer* ThreadedFileReader::GetBlockPtr(const Chunk& block,

bool ThreadedFileReader::Decompress(void* target, u64 begin, u32 size)
{
Chunk blk = ChunkForOffset(begin);
char* write = static_cast<char*>(target);
u32 remaining = size;
if (blk.offset != begin)
u64 off = begin;
while (remaining)
{
u32 off = begin - blk.offset;
u32 len = std::min(blk.length - off, size);
// Partial block
if (Buffer* buf = GetBlockPtr(blk))
Chunk chunk = ChunkForOffset(off);
if (m_internalBlockSize || chunk.offset != off || chunk.length > remaining)
{
if (buf->size < blk.length)
Buffer* buf = GetBlockPtr(chunk);
if (!buf)
return false;
u32 bufoff = off - buf->offset;
u32 bufsize = buf->size.load(std::memory_order_relaxed);
if (bufsize <= bufoff)
return false;
write += CopyBlocks(write, static_cast<char*>(buf->ptr) + off, len);
u32 len = std::min(bufsize - bufoff, remaining);
write += CopyBlocks(write, static_cast<char*>(buf->ptr) + bufoff, len);
remaining -= len;
blk = ChunkForOffset(blk.offset + blk.length);
}
else
{
return false;
}
}
while (blk.length <= remaining)
{
if (m_requestCancelled.load(std::memory_order_relaxed))
{
return false;
}
if (m_internalBlockSize)
{
if (Buffer* buf = GetBlockPtr(blk))
{
if (buf->size < blk.length)
return false;
write += CopyBlocks(write, buf->ptr, blk.length);
}
off += len;
}
else
{
int amt = ReadChunk(write, blk.chunkID);
if (amt < static_cast<int>(blk.length))
return false;
write += blk.length;
}
remaining -= blk.length;
blk = ChunkForOffset(blk.offset + blk.length);
}
if (remaining)
{
if (Buffer* buf = GetBlockPtr(blk))
{
if (buf->size < remaining)
int amt = ReadChunk(write, chunk.chunkID);
if (amt < static_cast<int>(chunk.length))
return false;
write += CopyBlocks(write, buf->ptr, remaining);
}
else
{
return false;
write += chunk.length;
remaining -= chunk.length;
off += chunk.length;
}
}
m_amtRead += write - static_cast<char*>(target);
Expand All @@ -218,19 +217,20 @@ bool ThreadedFileReader::TryCachedRead(void*& buffer, u64& offset, u32& size, co
for (int i = 0; i < static_cast<int>(ArraySize(m_buffer) * 2); i++)
{
Buffer& buf = m_buffer[i % ArraySize(m_buffer)];
if (!buf.valid.load(std::memory_order_acquire))
u32 bufsize = buf.size.load(std::memory_order_acquire);
if (!bufsize)
continue;
if (buf.offset <= offset && buf.offset + buf.size > offset)
if (buf.offset <= offset && buf.offset + bufsize > offset)
{
u32 off = offset - buf.offset;
u32 cpysize = std::min(size, buf.size - off);
u32 cpysize = std::min(size, bufsize - off);
size_t read = CopyBlocks(buffer, static_cast<char*>(buf.ptr) + off, cpysize);
m_amtRead += read;
size -= cpysize;
offset += cpysize;
buffer = static_cast<char*>(buffer) + read;
if (size == 0)
end = buf.offset + buf.size;
end = buf.offset + bufsize;
}
// Do buffers contain the current and next block?
if (end > 0 && buf.offset == end)
Expand Down Expand Up @@ -345,7 +345,7 @@ void ThreadedFileReader::Close(void)
{
CancelAndWaitUntilStopped();
for (auto& buf : m_buffer)
buf.valid.store(false, std::memory_order_relaxed);
buf.size.store(0, std::memory_order_relaxed);
Close2();
}

Expand Down
7 changes: 3 additions & 4 deletions pcsx2/CDVD/ThreadedFileReader.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -71,8 +71,8 @@ class ThreadedFileReader : public AsyncFileReader
{
void* ptr = nullptr;
u64 offset = 0;
u32 size = 0;
std::atomic<bool> valid{false};
std::atomic<u32> size{0};
u32 cap = 0;
};
/// 2 buffers for readahead (current block, next block)
Buffer m_buffer[2];
Expand All @@ -98,8 +98,7 @@ class ThreadedFileReader : public AsyncFileReader
void Loop();

/// Load the given block into one of the `m_buffer` buffers if necessary and return a pointer to its contents if successful
/// Writes to `m_status` if `!isReadahead`
Buffer* GetBlockPtr(const Chunk& block, bool isReadahead = false);
Buffer* GetBlockPtr(const Chunk& block);
/// Decompress from offset to size into
bool Decompress(void* ptr, u64 offset, u32 size);
/// Cancel any inflight read and wait until the thread is no longer doing anything
Expand Down

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