From: Parav Pandit <parav@nvidia.com>
To: Stefan Hajnoczi <stefanha@redhat.com>
Cc: "virtio-comment@lists.oasis-open.org"
<virtio-comment@lists.oasis-open.org>,
Shahaf Shuler <shahafs@nvidia.com>,
"hengqi@linux.alibaba.com" <hengqi@linux.alibaba.com>,
"virtio@lists.oasis-open.org" <virtio@lists.oasis-open.org>
Subject: [virtio-comment] RE: [virtio] [PATCH REQUIREMENTS v2 4/7] net-features: Add notification coalescing requirements
Date: Sun, 23 Jul 2023 21:39:33 +0000 [thread overview]
Message-ID: <PH0PR12MB548110479D1811D0419A136CDC3DA@PH0PR12MB5481.namprd12.prod.outlook.com> (raw)
In-Reply-To: <20230720151917.GB184015@fedora>
> From: Stefan Hajnoczi <stefanha@redhat.com>
> Sent: Thursday, July 20, 2023 11:19 AM
> > +## 3.3 Virtqueue notification coalescing re-enable support
>
> It's called "re-arming" above but "re-enable" here. Please choose one term and
> use it consistently.
>
Will change to re-arming as "enablement" can be easily confused with queue_enable and reset registers of pci.
> > +0. Design goal:
> > + a. Avoid constant notification from the device even in conditions when
> > + the driver may not have acted on the previous pending notification.
> > +1. When Tx and Rx virtqueue notification coalescing is enabled, and when
> such
> > + notification is reported by the device, device should be able to
> > +disable
>
> "notification" -> "a notification"
>
> ", device" -> ", the device"
>
> > + further notifications until the driver finish reacting to the
> > + already
>
> s/finish/finishes/
>
> > + generated notification.
> > +2. When the driver enables the notification coalescing reporting, the
> > +device
>
> "enables the notification coalescing reporting" -> "enables notification
> coalescing reporting"
>
> > + to notify again if notification coalescing conditions are met.
>
> I can't parse this sentence. Maybe "the device _has_ to notify again ..."?
>
> I find this text hard to understand. Is this a mechanism where the device does
> not send further notifications on a virtqueue until the driver has re-armed
> them?
>
Right.
I will rephrase it.
> How does this relate to EVENT_IDX, which can be used to achieve a similar
> effect? I guess the downside to EVENT_IDX is that the device must DMA
> repeatedly in order to detect changes from driver, whereas this new re-arming
> mechanism involves a hardware register write?
>
Correct. It is similar to EVENT_IDX without polling large scale unique addresses on the PCI.
> Can this new mechanism be generic for any kind of virtqueue, not just virtio-net
> rx/tx?
Maybe we can. Haven't found wider usage yet for it.
One needs to create a generic interface first to configure such things.
It was kind of implicit requirement that I didn't write it specific to this feature.
Config space was one way, but we discovered, debated and agreed that instead of config space, we should have a dma interface to exchange such info between driver and device.
Its now due for many features.
I suggest since receive flow filter has such requirement, we start with generic interface for it and expand to more like this one.
I will revise v3 to capture your inputs further.
This publicly archived list offers a means to provide input to the
OASIS Virtual I/O Device (VIRTIO) TC.
In order to verify user consent to the Feedback License terms and
to minimize spam in the list archive, subscription is required
before posting.
Subscribe: virtio-comment-subscribe@lists.oasis-open.org
Unsubscribe: virtio-comment-unsubscribe@lists.oasis-open.org
List help: virtio-comment-help@lists.oasis-open.org
List archive: https://lists.oasis-open.org/archives/virtio-comment/
Feedback License: https://www.oasis-open.org/who/ipr/feedback_license.pdf
List Guidelines: https://www.oasis-open.org/policies-guidelines/mailing-lists
Committee: https://www.oasis-open.org/committees/virtio/
Join OASIS: https://www.oasis-open.org/join/
next prev parent reply other threads:[~2023-07-23 21:39 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-07-02 23:44 [virtio-comment] [PATCH REQUIREMENTS v2 0/7] virtio net new features requirements Parav Pandit
2023-07-02 23:44 ` [virtio-comment] [PATCH REQUIREMENTS v2 1/7] net-features: Add requirements document for release 1.4 Parav Pandit
2023-07-20 2:10 ` [virtio-comment] Re: [virtio] " Xuan Zhuo
2023-07-20 2:15 ` [virtio-comment] " Parav Pandit
2023-07-02 23:44 ` [virtio-comment] [PATCH REQUIREMENTS v2 2/7] net-features: Add low latency transmit queue requirements Parav Pandit
2023-07-20 15:28 ` [virtio-comment] Re: [virtio] " Stefan Hajnoczi
2023-07-23 21:31 ` [virtio-comment] " Parav Pandit
2023-07-02 23:44 ` [virtio-comment] [PATCH REQUIREMENTS v2 3/7] net-features: Add low latency receive " Parav Pandit
2023-07-02 23:44 ` [virtio-comment] [PATCH REQUIREMENTS v2 4/7] net-features: Add notification coalescing requirements Parav Pandit
2023-07-20 15:19 ` [virtio-comment] Re: [virtio] " Stefan Hajnoczi
2023-07-23 21:39 ` Parav Pandit [this message]
2023-07-02 23:44 ` [virtio-comment] [PATCH REQUIREMENTS v2 5/7] net-features: Add n-tuple receive flow filters requirements Parav Pandit
2023-07-02 23:44 ` [virtio-comment] [PATCH REQUIREMENTS v2 6/7] net-features: Add packet timestamp requirements Parav Pandit
2023-07-02 23:44 ` [virtio-comment] [PATCH REQUIREMENTS v2 7/7] net-features: Add header data split requirements Parav Pandit
2023-07-20 2:20 ` [virtio-comment] [PATCH REQUIREMENTS v2 0/7] virtio net new features requirements Xuan Zhuo
2023-07-20 2:28 ` Parav Pandit
2023-07-20 2:36 ` Xuan Zhuo
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=PH0PR12MB548110479D1811D0419A136CDC3DA@PH0PR12MB5481.namprd12.prod.outlook.com \
--to=parav@nvidia.com \
--cc=hengqi@linux.alibaba.com \
--cc=shahafs@nvidia.com \
--cc=stefanha@redhat.com \
--cc=virtio-comment@lists.oasis-open.org \
--cc=virtio@lists.oasis-open.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).