32 lines
1.5 KiB
Text
32 lines
1.5 KiB
Text
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Specification for the Demo
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==========================
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:Date: Summer 2026
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:Author: Ichthyostega <Ichthyostega@web.de>
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:toc:
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:toclevels: 3
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This specification is the result of our research and provides a short summary of the relevant
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aspects of io_uring. Furthermore, the specific design of the demo code is explained and motivated.
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[red yellow-background]#TBW#
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IO_URING kernel interface
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-------------------------
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Liburing
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~~~~~~~~
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This helper library provides a thin wrapper to encapsulate most of the minute technical details
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related to the ringbuffers. The kernel interface as such is defined in a rather indirect way,
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so that most data definitions are exposed dynamically, at runtime in the form of relative field
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offsets. Also the structure of the ringbuffers is not defined directly as a data type; rather
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the well-known low-level C implementation of a index based ringbuffer is assumed like a coding
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template. Working with such a structure requires solid knowledge in system programming, including
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the proper usage of memory barriers. The Liburing handles all those tricky details behind a function
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based interface, that should be much more familiar to most programmers.
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To avoid a performance penalty due to this indirection and encapsulation, Liburing is defined
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to a large extent in the form of _static inline functions_. A variant called `liburing-ffi` is provided
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as alternative for cross-language bindings and for usage with older compilers, providing an definition
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and binary symbol for each function; obviously using these explicit calls adds a noticeable penalty.
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