mirror of
https://github.com/moses-smt/mosesdecoder.git
synced 2024-12-26 21:42:19 +03:00
70 lines
1.5 KiB
C++
70 lines
1.5 KiB
C++
#include "util/parallel_read.hh"
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#include "util/file.hh"
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#ifdef WITH_THREADS
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#include "util/thread_pool.hh"
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namespace util {
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namespace {
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class Reader {
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public:
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explicit Reader(int fd) : fd_(fd) {}
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struct Request {
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void *to;
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std::size_t size;
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uint64_t offset;
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bool operator==(const Request &other) const {
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return (to == other.to) && (size == other.size) && (offset == other.offset);
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}
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};
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void operator()(const Request &request) {
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util::ErsatzPRead(fd_, request.to, request.size, request.offset);
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}
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private:
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int fd_;
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};
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} // namespace
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void ParallelRead(int fd, void *to, std::size_t amount, uint64_t offset) {
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Reader::Request poison;
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poison.to = NULL;
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poison.size = 0;
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poison.offset = 0;
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unsigned threads = boost::thread::hardware_concurrency();
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if (!threads) threads = 2;
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ThreadPool<Reader> pool(2 /* don't need much of a queue */, threads, fd, poison);
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const std::size_t kBatch = 1ULL << 25; // 32 MB
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Reader::Request request;
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request.to = to;
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request.size = kBatch;
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request.offset = offset;
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for (; amount > kBatch; amount -= kBatch) {
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pool.Produce(request);
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request.to = reinterpret_cast<uint8_t*>(request.to) + kBatch;
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request.offset += kBatch;
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}
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request.size = amount;
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if (request.size) {
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pool.Produce(request);
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}
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}
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} // namespace util
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#else // WITH_THREADS
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namespace util {
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void ParallelRead(int fd, void *to, std::size_t amount, uint64_t offset) {
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util::ErsatzPRead(fd, to, amount, offset);
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}
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} // namespace util
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#endif
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