From: Avi Kivity <avi@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: davem@davemloft.net, Juan Quintela <quintela@redhat.com>,
Rusty Russell <rusty@rustcorp.com.au>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Arnd Bergmann <arnd@arndb.de>,
kvm@vger.kernel.org, virtualization@lists.osdl.org,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
alex.williamson@redhat.com, amit.shah@redhat.com
Subject: Re: [PATCHv2] vhost-net: utilize PUBLISH_USED_IDX feature
Date: Wed, 19 May 2010 19:15:09 +0300 [thread overview]
Message-ID: <4BF40E8D.7020409@redhat.com> (raw)
In-Reply-To: <4BF2D2A7.8030803@redhat.com>
On 05/18/2010 08:47 PM, Avi Kivity wrote:
> On 05/18/2010 05:21 AM, Michael S. Tsirkin wrote:
>> With PUBLISH_USED_IDX, guest tells us which used entries
>> it has consumed. This can be used to reduce the number
>> of interrupts: after we write a used entry, if the guest has not yet
>> consumed the previous entry, or if the guest has already consumed the
>> new entry, we do not need to interrupt.
>> This imporves bandwidth by 30% under some workflows.
>
> Seems to be missing the cacheline alignment.
>
> Rusty's clarification did not satisfy me, I think it's needed.
>
Oh, and this should definitely follow the patch to the virtio spec, not
precede it.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
next prev parent reply other threads:[~2010-05-19 16:15 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20100518022105.GA23129@redhat.com>
2010-05-18 11:31 ` [PATCHv2] vhost-net: utilize PUBLISH_USED_IDX feature Juan Quintela
2010-05-18 17:47 ` Avi Kivity
2010-05-19 16:15 ` Avi Kivity [this message]
2010-05-18 2:21 Michael S. Tsirkin
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