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[generator:features] Speedup nodes reading: mmap() + MADV_WILLNEED usage

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Anatoly Serdtcev 2019-11-19 08:27:52 +03:00 • committed by LaGrunge
parent d56ec9ed08
commit 2d8ecec4d5
1 changed files with 11 additions and 7 deletions
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18
generator/intermediate_data.cpp
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@ -134,18 +134,22 @@ class RawMemPointStorageReader : public PointStorageReaderInterface
public:
explicit RawMemPointStorageReader(string const & name)
{
auto fileStream = std::ifstream{};
fileStream.exceptions(std::ifstream::failbit);
fileStream.open(name, std::ios::binary);
m_fileMap.open(name);
if (!m_fileMap.is_open())
MYTHROW(Writer::OpenException, ("Failed to open", name));
static_assert(sizeof(size_t) == 8, "This code is only for 64-bit architectures");
fileStream.read(reinterpret_cast<char*>(m_data.data()), m_data.size() * sizeof(LatLon));
// Try aggressively (MADV_WILLNEED) and asynchronously read ahead the node file.
auto readaheadTask = std::thread([data = m_fileMap.data(), size = m_fileMap.size()] {
::madvise(const_cast<char*>(data), size, MADV_WILLNEED);
});
readaheadTask.detach();
}
// PointStorageReaderInterface overrides:
bool GetPoint(uint64_t id, double & lat, double & lon) const override
{
LatLon const & ll = m_data[id];
auto const * data = reinterpret_cast<LatLon const *>(m_fileMap.data());
LatLon const & ll = data[id];
bool ret = FromLatLon(ll, lat, lon);
if (!ret)
LOG(LERROR, ("Node with id =", id, "not found!"));
@ -153,7 +157,7 @@ public:
}
private:
vector<LatLon> m_data{kMaxNodesInOSM};
boost::iostreams::mapped_file_source m_fileMap;
};
// RawMemPointStorageWriter ------------------------------------------------------------------------