Changes in / [0a6da484:21923bd]

Location:

doc/theses/thierry_delisle_PhD/comp_II

Files:

• comp_II.tex (modified) (2 diffs)
• local.bib (modified) (3 diffs)

doc/theses/thierry_delisle_PhD/comp_II/comp_II.tex

@@ -447 +447 @@
 $select$ entails significant complexity and is being replaced in UNIX operating-systems, which make it a less interesting alternative.
 Another popular interface is $epoll$\cite{epoll}, which is supposed to be cheaper than $select$.
-However, $epoll$ also does not handle the file system and anectodal evidence suggest it has problem with linux pipes and $TTY$s.
-A popular cross-platform alternative is $libuv$\cite{libuv}, which offers asynchronous sockets and asynchronous file system operations (among other features).
+However, $epoll$ also does not handle the file system and seems to have problem to linux pipes and $TTY$s\cit.
+A very recent alternative that I am investigating is $io_uring$\cite{io_uring}.
+It claims to address some of the issues with $epoll$ but is too recent to be confident that it does.
+Finally, a popular cross-platform alternative is $libuv$\cite{libuv}, which offers asynchronous sockets and asynchronous file system operations (among other features).
 However, as a full-featured library it includes much more than I need and could conflict with other features of \CFA unless significant effort is made to merge them together.
-A very recent alternative that I am investigating is $io_uring$\cite{io_uring}.
-It claims to address some of the issues with $epoll$ and my early investigating suggest that the claim is accurate.
-$io_uring$ uses a much more general approach where system calls are register to a queue and later executed by the kernel, rather than relying on system calls to return an error instead of blocking and subsequently waiting for changes on file descriptors.
-I believe this approach allows for fewer problems, \eg the manpage for $open$\cite{open} states:
-\begin{quote}
-        Note that [the $O_NONBLOCK$ flag] has no effect for regular files and block devices;
-        that is, I/O operations will (briefly) block when device activity is required, regardless of whether $O_NONBLOCK$ is set.
-        Since $O_NONBLOCK$ semantics might eventually be implemented, applications should not depend upon blocking behavior when specifying this flag for regular files and block devices.
-\end{quote}
-This makes approach based on $epoll$/$select$ less reliable since they may not work for every file descriptors.
-For this reason, I plan to use $io_uring$ as the OS abstraction for the \CFA runtime, unless further work shows problems I haven't encountered yet.
-However, only a small subset of the features are available in Ubuntu as of April 2020\cite{wiki:ubuntu-linux}, which will limit performance comparisons.
-I do not believe this will affect the comparison result.
 
 \paragraph{Event Engine}
@@ -488 +477 @@
 % ===============================================================================
 \section{Discussion}
-I believe that runtime system and scheduling are still open topics.
-Many ``state of the art'' production frameworks still use single threaded event-loops because of performance considerations, \eg \cite{nginx-design}, and, to my knowledge, no wideyl available system language offers modern threading facilities.
-I believe the proposed work offers a novel runtime and scheduling package, where existing work only offers fragments that users must assemble themselves when possible.
+
 
 % ===============================================================================
 % ===============================================================================
 \section{Timeline}
-\begin{center}
-\begin{tabular}{ | r @{--} l | p{4in} | }
-\hline May 2020 & October 2020   & Creation of the performance benchmark. \\
-\hline November 2020 & March 2021   & Completion of the implementation. \\
-\hline March 2021 & April 2021  & Final Performance experiments. \\
-\hline May 2017 & August 2021 & Thesis writing and defense. \\
-\hline
-\end{tabular}
-\end{center}
+
 
 % B I B L I O G R A P H Y

doc/theses/thierry_delisle_PhD/comp_II/local.bib

@@ -265 +265 @@
 % Linux Man Pages
 % ===============================================================================
-@manual{open,
-  title      = "open(2) Linux User's Manual",
-  year       = "2020",
-  month      = "February",
-}
-
 @manual{epoll,
   title      = "epoll(7) Linux User's Manual",
@@ -312 +306 @@
   author={KARSTEN, MARTIN},
   journal={URL: https://git.uwaterloo.ca/mkarsten/libfibre}
-}
-
-@misc{nginx-design,
-  title={Inside NGINX: How We Designed for Performance \& Scale},
-  url = "https://www.nginx.com/blog/inside-nginx-how-we-designed-for-performance-scale/",
 }
 
@@ -346 +335 @@
    note = "[Online; accessed 14-April-2020]"
  }
-
- @misc{wiki:ubuntu-linux,
-   author = "{Wikipedia contributors}",
-   title = "Ubuntu version history : Table of versions --- {W}ikipedia{,} The Free Encyclopedia",
-   year = "2020",
-   url = "https://en.wikipedia.org/wiki/Ubuntu_version_history#Table_of_versions",
-   note = "[Online; accessed 15-April-2020]"
- }