Ignore:
Timestamp:
Oct 30, 2020, 12:35:59 PM (13 months ago)
Author:
Thierry Delisle <tdelisle@…>
Branches:
arm-eh, jacob/cs343-translation, master, new-ast-unique-expr
Children:
f7e4f8e8
Parents:
223a633
Message:

A whole bunch of thesis work and existing work

File:
1 edited

Legend:

Unmodified
Added
Removed
  • doc/theses/thierry_delisle_PhD/thesis/text/io.tex

    r223a633 rb9537e6  
    1 \chapter{I/O}
     1\chapter{User Level \glsxtrshort{io}}
     2As mentionned in Section~\ref{prev:io}, User-Level \glsxtrshort{io} requires multiplexing the \glsxtrshort{io} operations of many \glspl{thrd} onto fewer \glspl{proc} using asynchronous \glsxtrshort{io} operations. Various operating systems offer various forms of asynchronous operations and as mentioned in Chapter~\ref{intro}, this work is exclusively focuesd on Linux.
    23
    34\section{Existing options}
     5Since \glsxtrshort{io} operations are generally handled by the
    46
    57\subsection{\texttt{epoll}, \texttt{poll} and \texttt{select}}
     
    79\subsection{Linux's AIO}
    810
     11
     12
     13\begin{displayquote}
     14        AIO is a horrible ad-hoc design, with the main excuse being "other,
     15        less gifted people, made that design, and we are implementing it for
     16        compatibility because database people - who seldom have any shred of
     17        taste - actually use it".
     18
     19        But AIO was always really really ugly.
     20
     21        \begin{flushright}
     22                -- Linus Torvalds\cit{https://lwn.net/Articles/671657/}
     23        \end{flushright}
     24\end{displayquote}
     25
     26Interestingly, in this e-mail answer, Linus goes on to describe
     27``a true \textit{asynchronous system call} interface''
     28that does
     29``[an] arbitrary system call X with arguments A, B, C, D asynchronously using a kernel thread''
     30in
     31``some kind of arbitrary \textit{queue up asynchronous system call} model''.
     32This description is actually quite close to the interface of the interface described in the next section.
     33
    934\subsection{\texttt{io\_uring}}
     35A very recent addition to Linux, \texttt{io\_uring}\cit{io\_uring} is a framework that aims to solve many of the problems listed with the above mentioned solutions.
    1036
    11 \subsection{Extra Kernel Threads}
     37\subsection{Extra Kernel Threads}\label{io:morethreads}
     38Finally, if the operating system does not offer any satisfying forms of asynchronous \glsxtrshort{io} operations, a solution is to fake it by creating a pool of \glspl{kthrd} and delegating operations to them in order to avoid blocking \glspl{proc}.
    1239
    1340\subsection{Discussion}
Note: See TracChangeset for help on using the changeset viewer.