From: Yuanhan Liu <yuanhan.liu@linux.intel.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: dev@dpdk.org, marcel@redhat.com
Subject: Re: [dpdk-dev] [PATCH v7 4/8] vhost: rxtx: use queue id instead of constant ring index
Date: Fri, 23 Oct 2015 16:02:42 +0800 [thread overview]
Message-ID: <20151023080242.GV3115@yliu-dev.sh.intel.com> (raw)
In-Reply-To: <20151022171750-mutt-send-email-mst@redhat.com>
On Thu, Oct 22, 2015 at 05:19:01PM +0300, Michael S. Tsirkin wrote:
> On Thu, Oct 22, 2015 at 10:07:10PM +0800, Yuanhan Liu wrote:
> > On Thu, Oct 22, 2015 at 02:32:31PM +0300, Michael S. Tsirkin wrote:
> > > On Thu, Oct 22, 2015 at 05:49:55PM +0800, Yuanhan Liu wrote:
> > > > On Wed, Oct 21, 2015 at 05:26:18PM +0300, Michael S. Tsirkin wrote:
> > > > > On Wed, Oct 21, 2015 at 08:48:15PM +0800, Yuanhan Liu wrote:
> > > > > > > Please note that for virtio devices, guest is supposed to
> > > > > > > control the placement of incoming packets in RX queues.
> > > > > >
> > > > > > I may not follow you.
> > > > > >
> > > > > > Enqueuing packets to a RX queue is done at vhost lib, outside the
> > > > > > guest, how could the guest take the control here?
> > > > > >
> > > > > > --yliu
> > > > >
> > > > > vhost should do what guest told it to.
> > > > >
> > > > > See virtio spec:
> > > > > 5.1.6.5.5 Automatic receive steering in multiqueue mode
> > > >
> > > > Spec says:
> > > >
> > > > After the driver transmitted a packet of a flow on transmitqX,
> > > > the device SHOULD cause incoming packets for that flow to be
> > > > steered to receiveqX.
> > > >
> > > >
> > > > Michael, I still have no idea how vhost could know the flow even
> > > > after discussion with Huawei. Could you be more specific about
> > > > this? Say, how could guest know that? And how could guest tell
> > > > vhost which RX is gonna to use?
> > > >
> > > > Thanks.
> > > >
> > > > --yliu
> > >
> > > I don't really understand the question.
> > >
> > > When guests transmits a packet, it makes a decision
> > > about the flow to use, and maps that to a tx/rx pair of queues.
> > >
> > > It sends packets out on the tx queue and expects device to
> > > return packets from the same flow on the rx queue.
> > >
> > > During transmit, device needs to figure out the flow
> > > of packets as they are received from guest, and track
> > > which flows go on which tx queue.
> > > When it selects the rx queue, it has to use the same table.
> >
> > Thanks for the length explanation, Michael!
> >
> > I guess the key is are we able to get the table inside vhost-user
> > lib? And, are you looking for something like following?
> >
> > static int rte_vhost_enqueue_burst(pkts)
> > {
> > for_each_pkts(pkt) {
> > int rxq = get_rxq_from_table(pkt);
> >
> > queue_to_rxq(pkt, rxq);
> > }
> > }
> >
> > BTW, there should be such implementation at some where, right?
> > If so, would you please point it to me?
>
> See tun_flow_update in drivers/net/tun.c in Linux.
Thanks.
We had a discussion today, and we need implement that. However, the
v2.2 merge window is pretty near the end so far. So it's unlikely we
could make it in this release. We may add it in v2.3.
--yliu
>
>
> > In the meanwhile, I will read more doc/code to try to understand
> > it.
> >
> > --yliu
> >
> > >
> > > There is currently no provision for controlling
> > > steering for uni-directional
> > > flows which are possible e.g. with UDP.
> > >
> > > We might solve this in a future spec - for example, set a flag notifying
> > > guest that steering information is missing for a given flow, for example
> > > by setting a flag in a packet, or using the command queue, and have
> > > guest send a dummy empty packet to set steering rule for this flow.
> > >
> > >
> > > --
> > > MST
next prev parent reply other threads:[~2015-10-23 8:02 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-21 3:48 [dpdk-dev] [PATCH v7 0/8] vhost-user multiple queues enabling Yuanhan Liu
2015-10-21 3:48 ` [dpdk-dev] [PATCH v7 1/8] vhost-user: add protocol features support Yuanhan Liu
2015-10-22 9:52 ` Xie, Huawei
2015-10-21 3:48 ` [dpdk-dev] [PATCH v7 2/8] vhost-user: add VHOST_USER_GET_QUEUE_NUM message Yuanhan Liu
2015-10-22 9:38 ` Xie, Huawei
2015-10-21 3:48 ` [dpdk-dev] [PATCH v7 3/8] vhost: vring queue setup for multiple queue support Yuanhan Liu
2015-10-21 4:45 ` Stephen Hemminger
2015-10-21 6:52 ` Yuanhan Liu
2015-10-22 9:49 ` Xie, Huawei
2015-10-22 11:30 ` Yuanhan Liu
2015-10-21 3:48 ` [dpdk-dev] [PATCH v7 4/8] vhost: rxtx: use queue id instead of constant ring index Yuanhan Liu
2015-10-21 4:43 ` Stephen Hemminger
2015-10-21 6:54 ` Yuanhan Liu
2015-10-21 7:16 ` Xie, Huawei
2015-10-21 9:38 ` Ananyev, Konstantin
2015-10-21 15:47 ` Stephen Hemminger
2015-10-21 15:52 ` Thomas Monjalon
2015-10-21 15:57 ` Bruce Richardson
2015-10-21 15:55 ` Bruce Richardson
2015-10-21 16:29 ` Ananyev, Konstantin
2015-10-21 10:31 ` Michael S. Tsirkin
2015-10-21 12:48 ` Yuanhan Liu
2015-10-21 14:26 ` Michael S. Tsirkin
2015-10-21 14:59 ` Yuanhan Liu
2015-10-22 9:49 ` Yuanhan Liu
2015-10-22 11:32 ` Michael S. Tsirkin
2015-10-22 14:07 ` Yuanhan Liu
2015-10-22 14:19 ` Michael S. Tsirkin
2015-10-23 8:02 ` Yuanhan Liu [this message]
2015-10-24 2:34 ` Flavio Leitner
2015-10-24 17:47 ` Michael S. Tsirkin
2015-10-28 20:30 ` Flavio Leitner
2015-10-28 21:12 ` Michael S. Tsirkin
2015-11-16 22:20 ` Flavio Leitner
2015-11-17 8:23 ` Michael S. Tsirkin
2015-11-17 9:24 ` Jason Wang
2015-11-17 22:49 ` Flavio Leitner
2015-10-22 7:26 ` Xie, Huawei
2015-10-21 3:48 ` [dpdk-dev] [PATCH v7 5/8] virtio: fix deadloop due to reading virtio_net_config incorrectly Yuanhan Liu
2015-10-21 3:48 ` [dpdk-dev] [PATCH v7 6/8] vhost-user: enable vhost-user multiple queue Yuanhan Liu
2015-10-21 3:48 ` [dpdk-dev] [PATCH v7 7/8] vhost: add VHOST_USER_SET_VRING_ENABLE message Yuanhan Liu
2015-10-21 3:48 ` [dpdk-dev] [PATCH v7 8/8] doc: update release note for vhost-user mq support Yuanhan Liu
2015-10-22 12:35 ` [dpdk-dev] [PATCH v8 0/8] vhost-user multiple queues enabling Yuanhan Liu
2015-10-22 12:35 ` [dpdk-dev] [PATCH v8 1/8] vhost-user: add protocol features support Yuanhan Liu
2015-10-22 12:35 ` [dpdk-dev] [PATCH v8 2/8] vhost-user: add VHOST_USER_GET_QUEUE_NUM message Yuanhan Liu
2015-10-22 12:35 ` [dpdk-dev] [PATCH v8 3/8] vhost: vring queue setup for multiple queue support Yuanhan Liu
2015-10-26 5:24 ` Tetsuya Mukawa
2015-10-26 5:42 ` Yuanhan Liu
2015-10-27 6:20 ` Tetsuya Mukawa
2015-10-27 9:17 ` Michael S. Tsirkin
2015-10-27 9:30 ` Yuanhan Liu
2015-10-27 9:42 ` Michael S. Tsirkin
2015-10-27 9:51 ` Thomas Monjalon
2015-10-27 9:55 ` Michael S. Tsirkin
2015-10-27 10:41 ` Xie, Huawei
2015-10-27 9:53 ` Yuanhan Liu
2015-10-22 12:35 ` [dpdk-dev] [PATCH v8 4/8] vhost: rxtx: use queue id instead of constant ring index Yuanhan Liu
2015-10-22 12:35 ` [dpdk-dev] [PATCH v8 5/8] virtio: fix deadloop due to reading virtio_net_config incorrectly Yuanhan Liu
2015-10-22 12:35 ` [dpdk-dev] [PATCH v8 6/8] vhost: add VHOST_USER_SET_VRING_ENABLE message Yuanhan Liu
2015-10-22 12:35 ` [dpdk-dev] [PATCH v8 7/8] vhost-user: enable vhost-user multiple queue Yuanhan Liu
2015-10-22 12:35 ` [dpdk-dev] [PATCH v8 8/8] doc: update release note for vhost-user mq support Yuanhan Liu
2015-10-26 20:22 ` Thomas Monjalon
2015-10-27 9:38 ` Yuanhan Liu
2015-10-26 1:36 ` [dpdk-dev] [PATCH v8 0/8] vhost-user multiple queues enabling Xie, Huawei
2015-10-26 3:09 ` Yuanhan Liu
2015-10-26 20:26 ` Thomas Monjalon
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