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44 lines
787 B
C++
44 lines
787 B
C++
#pragma once
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#if defined(OS_LINUX)
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#include <cstdint>
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namespace DB
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{
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/** Opens a file /proc/self/statm. Keeps it open and reads memory statistics via 'pread'.
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* This is Linux specific.
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* See: man procfs
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*
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* Note: a class is used instead of a single function to avoid excessive file open/close on every use.
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* pread is used to avoid lseek.
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*
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* Actual performance is from 1 to 5 million iterations per second.
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*/
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class MemoryStatisticsOS
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{
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public:
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/// In number of bytes.
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struct Data
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{
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uint64_t virt;
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uint64_t resident;
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uint64_t shared;
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uint64_t code;
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uint64_t data_and_stack;
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};
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MemoryStatisticsOS();
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~MemoryStatisticsOS();
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/// Thread-safe.
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Data get() const;
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private:
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int fd;
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};
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}
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#endif
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