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Date: Mon, 07 Feb 2011 17:23:13 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] Re: [PATCH 2/7] Enable I/O thread and VNC threads
	by default
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To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>, Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>, qemu-devel@nongnu.org, Anthony Liguori <aliguori@linux.vnet.ibm.com>, Paul Brook <paul@codesourcery.com>, Arun Bharadwaj <arun@linux.vnet.ibm.com>, "Edgar E. Iglesias" <edgar.iglesias@gmail.com>

On 02/07/2011 05:03 PM, Marcelo Tosatti wrote:
> Is there any other issue that prevents turning CONFIG_IOTHREAD on by
> default?

I think Windows support.

Signal support is actually easy because we can "hack" the IPI as 
"suspend the VCPU thread+do work in the iothread context+resume the VCPU 
thread" (the IPI handler doesn't longjmp).

Threading primitives support is tricky but not hard (there is lots of 
code around, especially if you can make assumptions such as "always hold 
the mutex while signaling a cond. variable").

Paolo