From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jan Kiszka <jan.kiszka@web.de>
Subject: Re: assign-dev: Purpose of interrupt_work
Date: Mon, 12 Oct 2009 11:25:21 +0200
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Cc: Gleb Natapov <gleb@redhat.com>, kvm-devel <kvm@vger.kernel.org>
To: Avi Kivity <avi@redhat.com>
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Avi Kivity wrote:
> On 10/12/2009 11:04 AM, Jan Kiszka wrote:
>>> I'd rather remove dev-passthrough completely than continue adding
>>> hack upon hack
>>> upon hack to make is some times kinda sorta work :)
>>>     =20
>> Hmm, is this code not needed for the VT-d&  Co. case?
>=20
> It is needed.
>=20
>> Or what is the
>> alternative?
>>   =20
>=20
> irqfd (which only supports edge-triggered interrupts now).  Note irqfd
> needs the same love, it uses a workqueue as well.
>=20
> The theory is:
>  fd1 =3D eventfd()
>  give fd1 to kvm as irqfd, vhost-net as trigger fd
>  fd2 =3D eventfd()
>  give fd2 to kvm as irqfd, uio as trigger fd
>  fd3 =3D evenfd()
>  give fd3 to kvm as irqfd, another kvm as ioeventfd
>=20
> One interface, multiple users (in the kernel, userspace, or other
> processes)

I see to overall gain, but likely only worsens my objective (low
latency), at least it doesn't improve it.

Jan


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