Changeset 9153e53

Timestamp:

Jan 13, 2021, 10:35:02 PM (4 years ago)

Author:

Peter A. Buhr <pabuhr@…>

Branches:

ADT, arm-eh, ast-experimental, enum, forall-pointer-decay, jacob/cs343-translation, master, new-ast-unique-expr, pthread-emulation, qualifiedEnum

Children:

ec19b21

Parents:

402658b1

Message:

fix citation error

File:

• doc/theses/thierry_delisle_PhD/thesis/text/runtime.tex (modified) (1 diff)

doc/theses/thierry_delisle_PhD/thesis/text/runtime.tex

@@ -26 +26 @@
 \section{\glsxtrshort{io}}\label{prev:io}
 Prior to this work, the \CFA runtime did not add any particular support for \glsxtrshort{io} operations. %\CFA being built on C, this means that,
-While all I/O operations available in C are available in \CFA, \glsxtrshort{io} operations are designed for the POSIX threading model\cit{pthreads}. Using these 1:1 threading operations in an M:N threading model means I/O operations block \glspl{proc} instead of \glspl{thrd}. While this can work in certain cases, it limits the number of concurrent operations to the number of \glspl{proc} rather than \glspl{thrd}. It also means deadlock can occur because all \glspl{proc} are blocked even if at least one \gls{thrd} is ready to run. A simple example of this type of deadlock would be as follows:
+While all I/O operations available in C are available in \CFA, \glsxtrshort{io} operations are designed for the POSIX threading model~\cite{pthreads}. Using these 1:1 threading operations in an M:N threading model means I/O operations block \glspl{proc} instead of \glspl{thrd}. While this can work in certain cases, it limits the number of concurrent operations to the number of \glspl{proc} rather than \glspl{thrd}. It also means deadlock can occur because all \glspl{proc} are blocked even if at least one \gls{thrd} is ready to run. A simple example of this type of deadlock would be as follows:
 \begin{quote}
 Given a simple network program with 2 \glspl{thrd} and a single \gls{proc}, one \gls{thrd} sends network requests to a server and the other \gls{thrd} waits for a response from the server. If the second \gls{thrd} races ahead, it may wait for responses to requests that have not been sent yet. In theory, this should not be a problem, even if the second \gls{thrd} waits, because the first \gls{thrd} is still ready to run and should be able to get CPU time to send the request. With M:N threading, while the first \gls{thrd} is ready, the lone \gls{proc} \emph{cannot} run the first \gls{thrd} if it is blocked in the \glsxtrshort{io} operation of the second \gls{thrd}. If this happen, the system is in a synchronization deadlock\footnote{In this example, the deadlocked could be resolved if the server sends unprompted messages to the client. However, this solution is not general and may not be appropriate even in this simple case.}.