c5acd6e6f7
shared lock for reads and unique lock for writes declare cache as object and not pointer in serach engine data to simulate singleton declaration put a lock infront of the clear function to make it threadsafe remove clear function from cache because cache will never get dropped unit tests unit tests and timestamp as part of key cache generations hash the key 500 mb 1000 mb 250 mb rebase against implement-cache
104 lines
3.6 KiB
C++
104 lines
3.6 KiB
C++
#ifndef UNPACKING_CACHE_HPP
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#define UNPACKING_CACHE_HPP
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#include <boost/optional/optional_io.hpp>
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#include <boost/thread.hpp>
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#include "../../third_party/compute_detail/lru_cache.hpp"
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#include "util/typedefs.hpp"
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// sizeof size_t: 8
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// sizeof unsigned: 4
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// sizeof unchar: 1
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// sizeof uint32: 4
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namespace osrm
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{
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namespace engine
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{
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typedef unsigned char ExcludeIndex;
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typedef unsigned Timestamp;
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typedef std::tuple<NodeID, NodeID, ExcludeIndex, Timestamp> Key;
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class UnpackingCache
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{
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private:
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boost::compute::detail::lru_cache<Key, EdgeDuration> m_cache;
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boost::shared_mutex m_shared_access;
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public:
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// TO FIGURE OUT HOW MANY LINES TO INITIALIZE CACHE TO:
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// Assume max cache size is 500mb (see bottom of OP here:
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// https://github.com/Project-OSRM/osrm-backend/issues/4798#issue-288608332)
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// LRU CACHE IMPLEMENTATION HAS THESE TWO STORAGE CONTAINERS
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// Key is of size: std::uint32_t * 2 + (unsigned char) * 1
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// = 4 * 2 + 1 * 1 = 9
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// map: n * Key + n * EdgeDuration
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// = n * 9 bytes + n * std::int32_t
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// = n * 9 bytes + n * 4 bytes
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// = n * 13 bytes
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// list: n * Key
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// = n * 9 bytes
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// Total = n * (13 + 9) = n * 22 bytes
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// Total cache size: 500 mb = 500 * 1024 *1024 bytes = 524288000 bytes
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// Total cache size: 1024 mb = 1024 * 1024 *1024 bytes = 1073741824 bytes
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// Total cache size: 500 mb = 500 * 1024 *1024 bytes = 524288000 bytes
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// THREAD LOCAL STORAGE (500 mb)
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// Number of lines we need = 524288000 / 22 / number of threads = 23831272 / number of threads
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// 16 threads: 23831272 / 16 = 1489454
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// 8 threads: 23831272 / 8 = 2978909
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// 4 threads: 23831272 / 4 = 5957818
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// 2 threads: 23831272 / 2 = 11915636
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// THREAD LOCAL STORAGE (1024 mb)
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// Number of lines we need = 1073741824 / 22 / number of threads = 48806446 / number of threads
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// 16 threads: 48806446 / 16 = 3050402
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// 8 threads: 48806446 / 8 = 6100805
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// 4 threads: 48806446 / 4 = 12201611
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// 2 threads: 48806446 / 2 = 24403223
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// LRU CACHE IMPLEMENTATION HAS THESE TWO STORAGE CONTAINERS
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// Key is of size: std::uint32_t * 2 + (unsigned char) * 1 + unsigned * 1
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// = 4 * 2 + 1 * 1 + 4 * 1 = 13
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// map: n * Key + n * EdgeDuration
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// = n * 13 bytes + n * std::int32_t
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// = n * 13 bytes + n * 4 bytes
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// = n * 17 bytes
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// list: n * Key
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// = n * 13 bytes
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// Total = n * (17 + 13) = n * 30 bytes
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// Total cache size: 500 mb = 500 * 1024 *1024 bytes = 524288000 bytes
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// Total cache size: 1024 mb = 1024 * 1024 *1024 bytes = 1073741824 bytes
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// Total cache size: 500 mb = 500 * 1024 *1024 bytes = 524288000 bytes
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// SHARED STORAGE CACHE
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// Number of lines for shared storage cache 1024 mb = 524288000 / 30 = 17476266
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// Number of lines for shared storage cache 500 mb = 1073741824 / 30 = 35791394
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// Number of lines for shared storage cache 250 mb = 11397565 / 30 = 379918
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UnpackingCache() : m_cache(17476266){};
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bool IsEdgeInCache(Key edge)
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{
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boost::shared_lock<boost::shared_mutex> lock(m_shared_access);
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return m_cache.contains(edge);
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}
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void AddEdge(Key edge, EdgeDuration duration)
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{
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boost::unique_lock<boost::shared_mutex> lock(m_shared_access);
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m_cache.insert(edge, duration);
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}
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EdgeDuration GetDuration(Key edge)
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{
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boost::shared_lock<boost::shared_mutex> lock(m_shared_access);
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boost::optional<EdgeDuration> duration = m_cache.get(edge);
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return duration ? *duration : MAXIMAL_EDGE_DURATION;
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}
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};
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} // engine
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} // osrm
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#endif // UNPACKING_CACHE_HPP
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