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Date: Tue, 31 May 2011 09:26:41 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: Re: [Qemu-devel] [PATCH] Use SIGIO with caution
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To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: "qemu-trivial@nongnu.org" <qemu-trivial@nongnu.org>, =?UTF-8?B?QW5kcmU=?= =?UTF-8?B?YXMgRsOkcmJlcg==?= <andreas.faerber@web.de>, Marcelo Tosatti <mtosatti@redhat.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, Avi Kivity <avi@redhat.com>

On 05/31/2011 09:06 AM, Jan Kiszka wrote:
> On 2011-05-31 15:47, Anthony Liguori wrote:
>> On 05/29/2011 04:50 PM, Andreas Färber wrote:
>>> BeOS and Haiku don't define SIGIO. When undefined, it won't arrive
>>> and doesn't need to be blocked.
>>>
>>> Signed-off-by: Andreas Färber<andreas.faerber@web.de>
>>
>> Anything to do with signal masks is never a trivial patch BTW...
>>
>> But I actually think explicit handling of SIGIO is unneeded.  I think
>> this is a hold over from the pre-I/O thread days where we selectively
>> set SIGIO on certain file descriptors to make sure that when an IO fd
>> became readable, we received a signal to break out of the KVM emulation
>> loop.
>>
>> Can the folks on CC confirm/deny?
>>
>> I can't see any use of SIGIO in the current source tree.
>
> At least qemu-timer.c uses SIGIO in HPET mode. That only applies to
> Linux hosts, though.

Is there any reason we still carry multiple timer implementations these 
days?

HPET shouldn't be any better than dynticks.

Regards,

Anthony Liguori

>
> Jan
>