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From: Marcelo Tosatti <mtosatti@redhat.com>
To: Sheng Yang <sheng@linux.intel.com>
Cc: Avi Kivity <avi@redhat.com>, kvm@vger.kernel.org
Subject: Re: [PATCH 0/3] Emulate MSI-X mask bits for assigned devices
Date: Thu, 30 Sep 2010 13:44:51 -0300	[thread overview]
Message-ID: <20100930164451.GC29881@amt.cnet> (raw)
In-Reply-To: <1285667052-24907-1-git-send-email-sheng@linux.intel.com>

On Tue, Sep 28, 2010 at 05:44:09PM +0800, Sheng Yang wrote:
> Hi Avi & Marcelo
> 
> This patchset would add emulation of MSI-X mask bit for assigned devices in
> QEmu.
> 
> BTW: We are also purposed an acceleration of MSI-X mask bit for KVM - to get
> it done in kernel. That's because sometime MSI-X mask bit was accessed very
> frequently by guest and emulation in QEmu cost a lot(tens to hundreds percent
> CPU utilization sometime), e.g. guest using Linux 2.6.18 or under some heavy
> workload. The method has been proved efficient in Xen, but it would require
> VMM to handle MSI-X table. Is that OK with you?

It would be good to understand where that cost is, before. Eg. do you
commit kvm irq route frequently when guest unmasks?


  parent reply	other threads:[~2010-09-30 16:45 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-09-28  9:44 [PATCH 0/3] Emulate MSI-X mask bits for assigned devices Sheng Yang
2010-09-28  9:44 ` [PATCH 1/3] KVM: Emulation " Sheng Yang
2010-09-28 13:36   ` Michael S. Tsirkin
2010-09-29  1:17     ` Sheng Yang
2010-09-30 16:25       ` Marcelo Tosatti
2010-09-29  8:36   ` Avi Kivity
2010-09-30  5:41     ` Sheng Yang
2010-10-03 13:03       ` Avi Kivity
2010-10-11  9:32         ` Sheng Yang
2010-09-30 16:18   ` Marcelo Tosatti
2010-10-11  9:49     ` Sheng Yang
2010-10-11 17:11       ` Marcelo Tosatti
2010-10-03 11:12   ` Michael S. Tsirkin
2010-10-11  9:28     ` Sheng Yang
2010-10-11 10:01       ` Michael S. Tsirkin
2010-10-12  6:49         ` Sheng Yang
2010-10-12 18:28           ` Michael S. Tsirkin
2010-10-13  1:03             ` Sheng Yang
2010-10-13 10:35               ` Michael S. Tsirkin
2010-10-12 18:30           ` Michael S. Tsirkin
2010-10-13  0:58             ` Sheng Yang
2010-10-13 12:03               ` Michael S. Tsirkin
2010-09-28  9:44 ` [PATCH 2/3] qemu-kvm: device assignment: Some clean up for MSI-X code Sheng Yang
2010-09-28  9:44 ` [PATCH 3/3] qemu-kvm: device assignment: emulate MSI-X mask bits Sheng Yang
2010-09-30 16:44 ` Marcelo Tosatti [this message]
2010-10-11  9:34   ` [PATCH 0/3] Emulate MSI-X mask bits for assigned devices Sheng Yang

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