janwas
468a67d18c
- increase io depth and block size to better utilize FusionIO's crazy bandwidth - add OS error number to crashlog (error message may be localized and illegible) This was SVN commit r7054.
157 lines
3.4 KiB
C++
157 lines
3.4 KiB
C++
/* Copyright (C) 2009 Wildfire Games.
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* This file is part of 0 A.D.
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*
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* 0 A.D. is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 2 of the License, or
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* (at your option) any later version.
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*
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* 0 A.D. is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with 0 A.D. If not, see <http://www.gnu.org/licenses/>.
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*/
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/*
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* cache for aligned I/O blocks.
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*/
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#include "precompiled.h"
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#include "block_cache.h"
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#include "lib/config2.h" // CONFIG2_CACHE_READ_ONLY
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#include "lib/file/common/file_stats.h"
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#include "lib/lockfree.h"
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#include "lib/allocators/pool.h"
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#include "lib/fnv_hash.h"
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#include "io_align.h"
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//-----------------------------------------------------------------------------
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BlockId::BlockId()
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: m_id(0)
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{
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}
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BlockId::BlockId(const Path& pathname, off_t ofs)
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{
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m_id = fnv_hash64(pathname.string().c_str(), pathname.string().length());
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const size_t indexBits = 16;
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m_id <<= indexBits;
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const off_t blockIndex = off_t(ofs / BLOCK_SIZE);
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debug_assert(blockIndex < off_t(1) << indexBits);
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m_id |= blockIndex;
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}
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bool BlockId::operator==(const BlockId& rhs) const
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{
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return m_id == rhs.m_id;
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}
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bool BlockId::operator!=(const BlockId& rhs) const
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{
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return !operator==(rhs);
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}
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//-----------------------------------------------------------------------------
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struct Block
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{
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Block(BlockId id, const shared_ptr<u8>& buf)
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{
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this->id = id;
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this->buf = buf;
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}
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// block is "valid" and can satisfy Retrieve() requests if a
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// (non-default-constructed) ID has been assigned.
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BlockId id;
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// this block is "in use" if use_count != 1.
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shared_ptr<u8> buf;
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};
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//-----------------------------------------------------------------------------
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class BlockCache::Impl
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{
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public:
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Impl(size_t numBlocks)
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: m_maxBlocks(numBlocks)
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{
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}
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void Add(BlockId id, const shared_ptr<u8>& buf)
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{
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if(m_blocks.size() > m_maxBlocks)
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{
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#if CONFIG2_CACHE_READ_ONLY
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mprotect((void*)m_blocks.front().buf.get(), BLOCK_SIZE, PROT_READ);
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#endif
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m_blocks.pop_front(); // evict oldest block
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}
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#if CONFIG2_CACHE_READ_ONLY
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mprotect((void*)buf.get(), BLOCK_SIZE, PROT_WRITE|PROT_READ);
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#endif
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m_blocks.push_back(Block(id, buf));
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}
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bool Retrieve(BlockId id, shared_ptr<u8>& buf)
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{
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// (linear search is ok since we only expect to manage a few blocks)
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for(size_t i = 0; i < m_blocks.size(); i++)
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{
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Block& block = m_blocks[i];
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if(block.id == id)
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{
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buf = block.buf;
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return true;
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}
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}
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return false;
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}
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void InvalidateAll()
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{
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// note: don't check whether any references are held etc. because
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// this should only be called at the end of the (test) program.
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m_blocks.clear();
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}
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private:
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size_t m_maxBlocks;
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typedef std::deque<Block> Blocks;
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Blocks m_blocks;
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};
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//-----------------------------------------------------------------------------
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BlockCache::BlockCache(size_t numBlocks)
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: impl(new Impl(numBlocks))
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{
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}
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void BlockCache::Add(BlockId id, const shared_ptr<u8>& buf)
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{
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impl->Add(id, buf);
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}
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bool BlockCache::Retrieve(BlockId id, shared_ptr<u8>& buf)
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{
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return impl->Retrieve(id, buf);
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}
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void BlockCache::InvalidateAll()
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{
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return impl->InvalidateAll();
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}
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