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Date: Fri, 14 Feb 2003 17:12:27 -0800
From: "Randy.Dunlap" <rddunlap@osdl.org>
To: Jamie Lokier <jamie@shareable.org>
Cc: davidel@xmailserver.org, linux-kernel@vger.kernel.org
Subject: Re: Synchronous signal delivery..
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On Sat, 15 Feb 2003 01:01:53 +0000
Jamie Lokier <jamie@shareable.org> wrote:

| Davide Libenzi wrote:
...
| > 
| > Hmm ... using read() you'll lose the timeout capability, that IMHO is
| > pretty nice.
| 
| Very good point.
| 
| Timeouts could be events too - probably a good idea as they can then
| be absolute, relative, attached to different system clocks (monotonic
| vs. timeofday).  I think the POSIX timer work is like that.

Hi Davide, Jamie-

Yep.  And there are people (plural :) who would still like to get
that patch accepted into 2.5 too....

| It seems like a good idea to be able to attach one timeout event in
| the same system call as the event_read call itself - because it is
| _so_ common to vary the expiry time every time.
| 
| Then again, it is also extremely common to write this:
| 
| 	gettimeofday(...)
| 	// calculate time until next application timer expires.
| 	// Note also race condition here, if we're preempted.
| 	read_events(..., next_app_time - timeofday)
| 	// we need to know the current time.
| 	gettimeofday(...)
| 
| So perhaps the current select/poll/epoll timeout method is not
| particularly optimal as it is?

--
~Randy
-
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