Changeset a2fd937 for doc/theses/thierry_delisle_PhD/thesis/text/io.tex

Timestamp:

Sep 15, 2022, 11:48:19 AM (20 months ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, ast-experimental, master, pthread-emulation

Children:

2c63fa2

Parents:

95e5018

Message:

Finished last todo

File:

• doc/theses/thierry_delisle_PhD/thesis/text/io.tex (modified) (2 diffs)

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

@@ -30 +30 @@
 Hence, if one \gls{kthrd} is managing the select calls, other threads can only add/remove to/from the manager's interest set through synchronized calls to update the interest set.
 However, these changes are only reflected when the manager makes its next call to @select@.
-Note, it is possible for the manager thread to never unblock if its current interest set never changes, \eg the sockets/pipes/ttys it is waiting on never get data again.
+Note, it is possible for the manager thread to never unblock if its current interest set never changes, \eg the sockets/pipes/TTYs it is waiting on never get data again.
 Often the I/O manager has a timeout, polls, or is sent a signal on changes to mitigate this problem.
 
@@ -46 +46 @@
 However, all three of these I/O systems have limitations.
 The @man@ page for @O_NONBLOCK@ mentions that ``[@O_NONBLOCK@] has no effect for regular files and block devices'', which means none of these three system calls are viable multiplexing strategies for these types of \io operations.
-Furthermore, @epoll@ has been shown to have problems with pipes and ttys~\cit{Peter's examples in some fashion}.
+Furthermore, TTYs can also be tricky to use since they can take different forms based on how the command is executed.
+For example, @epoll@ rejects FDs pointing to regular files or block devices, which includes @stdin@ when using shell redirections~\cite[\S~3.6]{MAN:bash}, but does not reject shell pipelines~\cite[\S~3.2.3]{MAN:bash}, which includes pipelines into @stdin@.
 Finally, none of these are useful solutions for multiplexing \io operations that do not have a corresponding file descriptor and can be awkward for operations using multiple file descriptors.