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Date: Thu, 24 Jul 2008 12:37:58 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
MIME-Version: 1.0
Subject: Re: [Qemu-devel] [PATCH 2/3] Always use nonblocking
	mode	for	qemu_chr_open_fd.
References: <E1KJqa3-00067A-KN@mariner.uk.xensource.com>	<48874D4A.8000604@codemonkey.ws>
	<48875849.60200@redhat.com>
	<200807231744.28969.paul@codesourcery.com>
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To: qemu-devel@nongnu.org
Cc: Gerd Hoffmann <kraxel@redhat.com>

Paul Brook wrote:
> On Wednesday 23 July 2008, Gerd Hoffmann wrote:
>   
>> Anthony Liguori wrote:
>>     
>>> Gerd Hoffmann wrote:
>>>       
>>>> Comments on this one?
>>>>         
>>> Checking every 100ms for every pty device really makes me cringe.
>>>       
>> Only when unconnected, and the interval can be changed.
>> And I'm certainly open for better ideas ...
>>     
>
> Anything that requires periodic polling is almost certainly wrong.
>
> If it's unconnected then why do we need to poll at all? If we're discarding 
> data then we aren't going to retry, so it should be sufficient to check 
> whenever we send data.
>   

There's no way to determine if someone reconnected without trying to do 
a read().  pty's just aren't designed for this sort of thing.

Regards,

Anthony Liguori

> Paul
>
>
>