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From: Anthony Liguori <aliguori@us.ibm.com>
In-Reply-To: <50757894.2000703@redhat.com>
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Date: Wed, 10 Oct 2012 09:44:50 -0500
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Subject: Re: [Qemu-devel] Block I/O outside the QEMU global mutex was "Re:
	[RFC PATCH 00/17] Support for multiple "AIO contexts""
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To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Stefan Hajnoczi <stefanha@gmail.com>, Ping Fan Liu <pingfank@linux.vnet.ibm.com>, qemu-devel@nongnu.org, Avi Kivity <avi@redhat.com>

Paolo Bonzini <pbonzini@redhat.com> writes:

> Il 10/10/2012 14:25, Anthony Liguori ha scritto:
>>> > NBD uses coroutines; curl can use the non-unlocked
>>> > bdrv_aio_readv/writev.  In both cases they would execute in the
>>> > dataplane thread.  qcow2-over-raw would also execute its read/write code
>>> > entirely from the dataplane thread, for example.
>> Does that mean that we'd stop processing the queue if we're waiting for
>> an I/O completion to handle meta data operations?
>> 
>> If that's the case, that probably will hurt performance overall.
>
>>>From discussion on IRC it looked like this was ENOCAFFEINE. :)
>
> Paolo

Correct :-)

Regards,

Anthony Liguori