From: Eric Wong <normalperson@...>
Date: 2011-03-03T04:37:07+09:00
Subject: Re: question: threads behaviour

Robert Klemme <shortcutter@googlemail.com> wrote:
> On Tue, Mar 1, 2011 at 11:13 PM, Eric Wong <normalperson@yhbt.net> wrote:
> > Filesystem IO (regular files) doesn't return EAGAIN (at least not on
> > systems I'm familiar with).
> 
> http://www.kernel.org/doc/man-pages/online/pages/man2/read.2.html#ERRORS

From http://www.kernel.org/doc/man-pages/online/pages/man2/read.2.html#NOTES

  Many file systems and disks were considered to be fast enough
  that the implementation of O_NONBLOCK was deemed unnecessary.
  So, O_NONBLOCK may not be available on files and/or disks.

From what I've seen, setting O_NONBLOCK doesn't error, but read() never
actually respects it on ext{2,3,4} even when a disk is horribly slow.

-- 
Eric Wong