virtio — archive

[PATCH requirements 0/7] virtio net new features requirements

From: Jason Wang <[email protected]>
To: [email protected]
Date: Thu, 10 Aug 2023 06:56:00 -0000

On Wed, Aug 9, 2023 at 4:47?PM Xuan Zhuo <[email protected]> wrote: > > On Mon, 24 Jul 2023 06:34:20 +0300, Parav Pandit <[email protected]> wrote: > > Add tx and rx packet timestamp requirements. > > > > Signed-off-by: Parav Pandit <[email protected]> > > --- > > net-workstream/features-1.4.md | 26 ++++++++++++++++++++++++++ > > 1 file changed, 26 insertions(+) > > > > diff --git a/net-workstream/features-1.4.md b/net-workstream/features-1.4.md > > index d228462..37820b6 100644 > > --- a/net-workstream/features-1.4.md > > +++ b/net-workstream/features-1.4.md > > @@ -10,6 +10,7 @@ together is desired while updating the virtio net interface. > > 2. Low latency tx and rx virtqueues for PCI transport > > 3. Virtqueue notification coalescing re-arming support > > 4 Virtqueue receive flow filters (RFF) > > +5. Device timestamp for tx and rx packets > > > > # 3. Requirements > > ## 3.1 Device counters > > @@ -280,3 +281,28 @@ struct virtio_net_rff_delete { > > u8 padding[2]; > > le32 flow_id; > > }; > > + > > +## 3.5 Packet timestamp > > +1. Device should provide transmit timestamp and receive timestamp of the packets > > + at per packet level when the device is enabled. > > +2. Device should provide the current free running clock in the least latency > > + possible using an MMIO register read of 64-bit to have the least jitter. > > +3. Device should provide the current frequency and the frequency unit for the > > + software to synchronize the reference point of software and the device using > > + a control vq command. > > + > > +### 3.5.1 Transmit timestamp > > +1. Transmit completion must contain a packet transmission timestamp when the > > + device is enabled for it. > > +2. The device should record the packet transmit timestamp in the completion at > > + the farthest egress point towards the network. > > +3. The device must provide a transmit packet timestamp in a single DMA > > + transaction along with the rest of the transmit completion fields. > > + > > +### 3.5.2 Receive timestamp > > +1. Receive completion must contain a packet reception timestamp when the device > > + is enabled for it. > > +2. The device should record the received packet timestamp at the closet ingress > > + point of reception from the network. > > +3. The device should provide a receive packet timestamp in a single DMA > > + transaction along with the rest of the receive completion fields. > > > According to the last discuss, the feature will depend on the new desc > structure. > > I would to know, can we introduce this to the current spec with a simple change? > > struct vring_used_elem { > /* Index of start of used descriptor chain. */ > __virtio32 id; > /* Total length of the descriptor chain which was used (written to) */ > __virtio32 len; > > + __virtio64 timestamp; > }; I think this could be one way and another proposal from Willem is: https://lists.linuxfoundation.org/pipermail/virtualization/2021-February/052422.html which might be tricky for TX but it's more flexible since it allows timestamps to be done per buffer. > > > Then, the existing devices can support this easily. If we introduce this by the > new desc structure, we can foresee that this function will not be implemented by > many existing machines. But this function is useful. So we want support this by > a simple way. Make sense. Thanks > > > Thanks. > > > -- > > 2.26.2 > > > > > > --------------------------------------------------------------------- > > To unsubscribe from this mail list, you must leave the OASIS TC that > > generates this mail. Follow this link to all your TCs in OASIS at: > > https://www.oasis-open.org/apps/org/workgroup/portal/my_workgroups.php > > > > 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: [email protected] > Unsubscribe: [email protected] > List help: [email protected] > 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/ >