From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Jason Wang <jasowang@redhat.com>
Cc: "Michael S. Tsirkin" <mst@redhat.com>,
virtio-dev@lists.oasis-open.org,
virtualization@lists.linux-foundation.org
Subject: Re: [virtio-dev] Re: packed ring layout proposal v3
Date: Tue, 12 Sep 2017 12:23:56 -0400 [thread overview]
Message-ID: <CAF=yD-+LtZO=Fcw6Y-v0dnxkmwqW1+CqzopyQEApOjOAszgqMg@mail.gmail.com> (raw)
In-Reply-To: <0f0e1b94-2a46-689c-dbb3-0d578cc8df33@redhat.com>
On Mon, Sep 11, 2017 at 3:47 AM, Jason Wang <jasowang@redhat.com> wrote:
>
>
> On 2017年09月10日 13:06, Michael S. Tsirkin wrote:
>>
>> This is an update from v2 version.
>> Changes:
>> - update event suppression mechanism
>> - add wrap counter: DESC_WRAP flag in addition to
>> DESC_DRIVER flag used for validity so device does not have to
>> write out all used descriptors.
>
>
> Do we have benchmark result to show the advantage of DESC_DRIVER over e.g
> avail/used index?
The KVM forum presentation has some numbers.
I'm not sure that synthetic benchmarks will provide much value, as we
understand the trade-off quite well.
The benefit of this model is improved best case performance, by having
a single cacheline read instead of two for the indirect used/avail ring model.
The drawback is worse worst case, as scanning the ring of descriptors
introduces more cacheline misses than scanning the compressed
used/avail ring.
This model is easier to implement in hardware and the common case is
likely close to the best case, so I think it makes sense.
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next prev parent reply other threads:[~2017-09-12 16:24 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-10 5:06 [virtio-dev] packed ring layout proposal v3 Michael S. Tsirkin
2017-02-08 13:37 ` packed ring layout proposal v2 Christian Borntraeger
2017-02-09 17:43 ` Michael S. Tsirkin
[not found] ` <20170209181955-mutt-send-email-mst@kernel.org>
2017-02-09 18:27 ` Christian Borntraeger
2017-02-08 17:41 ` [virtio-dev] " Paolo Bonzini
2017-02-08 19:59 ` Michael S. Tsirkin
[not found] ` <20170208214435-mutt-send-email-mst@kernel.org>
2017-02-09 15:48 ` Paolo Bonzini
2017-02-09 16:11 ` Cornelia Huck
2017-02-09 18:24 ` Michael S. Tsirkin
[not found] ` <20170209202203-mutt-send-email-mst@kernel.org>
2017-02-10 11:32 ` Paolo Bonzini
[not found] ` <c229269b-1702-ffec-62e8-002c7c142904@redhat.com>
2017-02-10 15:20 ` Michael S. Tsirkin
2017-02-10 16:17 ` Paolo Bonzini
[not found] ` <20170209171105.075a9d9c.cornelia.huck@de.ibm.com>
2017-02-22 16:43 ` Michael S. Tsirkin
[not found] ` <20170222181333-mutt-send-email-mst@kernel.org>
2017-03-07 15:53 ` Cornelia Huck
2017-03-07 20:33 ` Michael S. Tsirkin
[not found] ` <20170307223057-mutt-send-email-mst@kernel.org>
2017-07-10 16:27 ` Amnon Ilan
2017-07-10 16:27 ` Amnon Ilan
2017-02-22 4:27 ` packed ring layout proposal - todo list Michael S. Tsirkin
[not found] ` <20170222054336-mutt-send-email-mst@kernel.org>
2017-02-22 9:19 ` [virtio-dev] " Gray, Mark D
[not found] ` <738D45BC1F695740A983F43CFE1B7EA94E93CA7E@IRSMSX108.ger.corp.intel.com>
2017-02-22 15:13 ` Michael S. Tsirkin
2017-02-28 4:29 ` Yuanhan Liu
[not found] ` <20170228042943.GH18844@yliu-dev.sh.intel.com>
2017-03-01 1:07 ` Michael S. Tsirkin
2017-03-08 7:09 ` Yuanhan Liu
[not found] ` <20170308070948.GC18844@yliu-dev.sh.intel.com>
2017-03-08 7:56 ` Yuanhan Liu
[not found] ` <20170308075624.GF18844@yliu-dev.sh.intel.com>
2017-03-29 12:39 ` Michael S. Tsirkin
2017-04-01 7:30 ` Yuanhan Liu
2017-02-22 14:46 ` [virtio-dev] packed ring layout proposal v2 Chien, Roger S
2017-02-28 5:02 ` Yuanhan Liu
2017-02-28 5:47 ` [RFC] packed (virtio-net) headers Yuanhan Liu
[not found] ` <20170228050218.GI18844@yliu-dev.sh.intel.com>
2017-03-01 1:02 ` [virtio-dev] packed ring layout proposal v2 Michael S. Tsirkin
[not found] ` <20170301024951-mutt-send-email-mst@kernel.org>
2017-03-01 3:57 ` Yuanhan Liu
[not found] ` <20170301035715.GP18844@yliu-dev.sh.intel.com>
2017-03-01 4:14 ` Michael S. Tsirkin
2017-03-01 4:57 ` Yuanhan Liu
[not found] ` <20170228054719.GJ18844@yliu-dev.sh.intel.com>
2017-03-01 1:28 ` [RFC] packed (virtio-net) headers Michael S. Tsirkin
2017-07-16 6:00 ` [virtio-dev] packed ring layout proposal v2 Lior Narkis
2017-07-18 16:23 ` Michael S. Tsirkin
2017-07-18 16:23 ` Michael S. Tsirkin
2017-07-19 7:41 ` Lior Narkis
2017-07-20 13:06 ` Michael S. Tsirkin
2017-07-20 13:06 ` Michael S. Tsirkin
2017-07-19 7:41 ` Lior Narkis
2017-07-16 6:00 ` Lior Narkis
2017-09-11 7:47 ` [virtio-dev] Re: packed ring layout proposal v3 Jason Wang
2017-09-12 16:23 ` Willem de Bruijn [this message]
2017-09-13 1:26 ` Jason Wang
2017-09-13 1:26 ` Jason Wang
2017-09-12 16:23 ` Willem de Bruijn
2017-09-11 7:47 ` Jason Wang
2017-09-12 16:20 ` [virtio-dev] " Willem de Bruijn
2017-09-12 16:20 ` Willem de Bruijn
2017-09-14 8:23 ` Ilya Lesokhin
2017-09-20 9:11 ` [virtio-dev] " Liang, Cunming
2017-09-20 9:11 ` Liang, Cunming
2017-09-25 22:24 ` Michael S. Tsirkin
2017-09-25 22:24 ` Michael S. Tsirkin
2017-09-26 23:38 ` Steven Luong (sluong)
2017-09-27 23:49 ` Michael S. Tsirkin
2017-09-27 23:49 ` Michael S. Tsirkin
2017-09-28 9:44 ` Liang, Cunming
2017-10-01 4:08 ` Michael S. Tsirkin
2017-10-01 4:08 ` Michael S. Tsirkin
2017-10-04 12:39 ` Jens Freimann
2017-10-04 12:58 ` Michael S. Tsirkin
2017-10-04 12:58 ` Michael S. Tsirkin
2017-10-10 9:56 ` Liang, Cunming
2017-10-10 9:56 ` Liang, Cunming
2017-10-11 12:22 ` Jens Freimann
2017-09-28 9:44 ` Liang, Cunming
2017-09-28 21:13 ` Michael S. Tsirkin
2017-09-28 21:13 ` Michael S. Tsirkin
2017-09-26 23:38 ` Steven Luong (sluong)
2017-09-21 13:36 ` Liang, Cunming
2017-09-21 13:36 ` Liang, Cunming
2017-09-28 21:27 ` Michael S. Tsirkin
2017-09-28 21:27 ` Michael S. Tsirkin
2017-10-08 6:16 ` Ilya Lesokhin
2017-10-08 6:16 ` [virtio-dev] " Ilya Lesokhin
2017-10-25 16:20 ` Michael S. Tsirkin
2017-10-25 16:20 ` [virtio-dev] " Michael S. Tsirkin
2017-10-29 9:05 ` Ilya Lesokhin
2017-10-29 9:05 ` [virtio-dev] " Ilya Lesokhin
2017-10-29 14:21 ` Michael S. Tsirkin
2017-10-29 14:21 ` [virtio-dev] " Michael S. Tsirkin
2017-10-29 14:34 ` Ilya Lesokhin
2017-10-29 14:34 ` [virtio-dev] " Ilya Lesokhin
2017-10-30 2:08 ` Michael S. Tsirkin
2017-10-30 2:08 ` [virtio-dev] " Michael S. Tsirkin
2017-10-30 6:30 ` [virtio-dev] " Ilya Lesokhin
2017-10-30 16:30 ` Michael S. Tsirkin
2017-10-30 16:30 ` [virtio-dev] " Michael S. Tsirkin
2017-10-30 6:30 ` Ilya Lesokhin
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