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Re: [Qemu-devel] [snabb-devel] Re: [PATCH v2] vhost-user: add multi queu
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From: |
Ouyang, Changchun |
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Subject: |
Re: [Qemu-devel] [snabb-devel] Re: [PATCH v2] vhost-user: add multi queue support |
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Date: |
Thu, 9 Apr 2015 02:18:43 +0000 |
Hi guys,
> -----Original Message-----
> From: address@hidden [mailto:snabb-
> address@hidden On Behalf Of Michael S. Tsirkin
> Sent: Monday, April 6, 2015 11:07 PM
> To: Nikolay Nikolaev
> Cc: Long, Thomas; address@hidden; address@hidden;
> address@hidden; address@hidden
> Subject: [snabb-devel] Re: [PATCH v2] vhost-user: add multi queue support
>
> On Sat, Jan 24, 2015 at 02:22:29PM +0200, Nikolay Nikolaev wrote:
> > Vhost-user will implement the multiqueueu support in a similar way to
> > what
>
> multiqueue
>
> > vhost already has - a separate thread for each queue.
> >
> > To enable the multiqueue funcionality - a new command line parameter
> > "queues" is introduced for the vhost-user netdev.
> >
> > Changes since v1:
> > - use s->nc.info_str when bringing up/down the backend
> >
> > Signed-off-by: Nikolay Nikolaev <address@hidden>
> > ---
> > docs/specs/vhost-user.txt | 5 +++++
> > hw/virtio/vhost-user.c | 6 +++++-
> > net/vhost-user.c | 39 +++++++++++++++++++++++++--------------
> > qapi-schema.json | 6 +++++-
> > qemu-options.hx | 5 +++--
> > 5 files changed, 43 insertions(+), 18 deletions(-)
> >
> > diff --git a/docs/specs/vhost-user.txt b/docs/specs/vhost-user.txt
> > index 650bb18..d7b208c 100644
> > --- a/docs/specs/vhost-user.txt
> > +++ b/docs/specs/vhost-user.txt
>
> I've been thinking that the protocol might be a useful addition to the virtio
> spec. For this, as a minimum you would have to submit this document as a
> comment to virtio TC with a proposal to include it in the virtio spec.
> See
> https://www.oasis-
> open.org/committees/comments/index.php?wg_abbrev=virtio
>
> Can you do this?
>
> We can take it from there, though I would encourage your company to join
> as a contributor.
>
>
> > @@ -127,6 +127,11 @@ in the ancillary data:
> > If Master is unable to send the full message or receives a wrong
> > reply it will close the connection. An optional reconnection mechanism can
> be implemented.
> >
> > +Multi queue suport
> > +---------------------
> > +The protocol supports multiple queues by setting all index fields in
> > +the sent messages to a properly calculated value.
> > +
>
> Something that's not clear from this document is what happens with control
> VQ.
> Can you clarify please?
>
>
> > Message types
> > -------------
> >
> > diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c index
> > aefe0bb..83ebcaa 100644
> > --- a/hw/virtio/vhost-user.c
> > +++ b/hw/virtio/vhost-user.c
> > @@ -253,17 +253,20 @@ static int vhost_user_call(struct vhost_dev *dev,
> unsigned long int request,
> > case VHOST_SET_VRING_NUM:
> > case VHOST_SET_VRING_BASE:
> > memcpy(&msg.state, arg, sizeof(struct vhost_vring_state));
> > + msg.state.index += dev->vq_index;
> > msg.size = sizeof(m.state);
> > break;
> >
> > case VHOST_GET_VRING_BASE:
> > memcpy(&msg.state, arg, sizeof(struct vhost_vring_state));
> > + msg.state.index += dev->vq_index;
> > msg.size = sizeof(m.state);
> > need_reply = 1;
> > break;
> >
> > case VHOST_SET_VRING_ADDR:
> > memcpy(&msg.addr, arg, sizeof(struct vhost_vring_addr));
> > + msg.addr.index += dev->vq_index;
> > msg.size = sizeof(m.addr);
> > break;
> >
> > @@ -271,7 +274,7 @@ static int vhost_user_call(struct vhost_dev *dev,
> unsigned long int request,
> > case VHOST_SET_VRING_CALL:
> > case VHOST_SET_VRING_ERR:
> > file = arg;
> > - msg.u64 = file->index & VHOST_USER_VRING_IDX_MASK;
> > + msg.u64 = (file->index + dev->vq_index) &
> > + VHOST_USER_VRING_IDX_MASK;
I identify one vq_index issue here when it is the case of VHOST_SET_VRING_CALL,
The vq_index is not initialized before it is used here, so it could be a random
value.
It leads to error in vhost, when this random value is passed to vhost and vhost
use this random value to set the vring call.
I have a quick fix for this, code changes as the following:
diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index 4e3a061..2fbdb93 100644
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -157,6 +157,7 @@ struct vhost_net *vhost_net_init(VhostNetOptions *options)
net->dev.nvqs = 2;
net->dev.vqs = net->vqs;
+ net->dev.vq_index = net->nc->queue_index;
r = vhost_dev_init(&net->dev, options->opaque,
options->backend_type, options->force);
diff --git a/net/vhost-user.c b/net/vhost-user.c
index a0b4af2..b27190f 100644
--- a/net/vhost-user.c
+++ b/net/vhost-user.c
@@ -152,6 +152,7 @@ static int net_vhost_user_init(NetClientState *peer, const
char *device,
s->nc.receive_disabled = 1;
s->chr = chr;
s->vhostforce = vhostforce;
+ s->nc.queue_index = i;
qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event, s);
}
Would you guys have a look at this issue?
And I also met other issues when I try to run with 2 virtio ports, each one has
2 queues
But not root cause yet, need further investigate,
So I think it may have more issues in qemu for vhost user multiple queues
enabling.
> > msg.size = sizeof(m.u64);
> > if (ioeventfd_enabled() && file->fd > 0) {
> > fds[fd_num++] = file->fd; @@ -313,6 +316,7 @@ static int
> > vhost_user_call(struct vhost_dev *dev, unsigned long int request,
> > error_report("Received bad msg size.\n");
> > return -1;
> > }
> > + msg.state.index -= dev->vq_index;
> > memcpy(arg, &msg.state, sizeof(struct vhost_vring_state));
> > break;
> > default:
> > diff --git a/net/vhost-user.c b/net/vhost-user.c index
> > 24e050c..a0b4af2 100644
> > --- a/net/vhost-user.c
> > +++ b/net/vhost-user.c
> > @@ -122,37 +122,39 @@ static void net_vhost_user_event(void *opaque,
> int event)
> > case CHR_EVENT_OPENED:
> > vhost_user_start(s);
> > net_vhost_link_down(s, false);
> > - error_report("chardev \"%s\" went up\n", s->chr->label);
> > + error_report("chardev \"%s\" went up\n", s->nc.info_str);
> > break;
> > case CHR_EVENT_CLOSED:
> > net_vhost_link_down(s, true);
> > vhost_user_stop(s);
> > - error_report("chardev \"%s\" went down\n", s->chr->label);
> > + error_report("chardev \"%s\" went down\n", s->nc.info_str);
> > break;
> > }
> > }
> >
> > static int net_vhost_user_init(NetClientState *peer, const char *device,
> > const char *name, CharDriverState *chr,
> > - bool vhostforce)
> > + bool vhostforce, uint32_t queues)
> > {
> > NetClientState *nc;
> > VhostUserState *s;
> > + int i;
> >
> > - nc = qemu_new_net_client(&net_vhost_user_info, peer, device,
> name);
> > + for (i = 0; i < queues; i++) {
> > + nc = qemu_new_net_client(&net_vhost_user_info, peer, device,
> > + name);
> >
> > - snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user to %s",
> > - chr->label);
> > + snprintf(nc->info_str, sizeof(nc->info_str), "vhost-user%d to %s",
> > + i, chr->label);
> >
> > - s = DO_UPCAST(VhostUserState, nc, nc);
> > + s = DO_UPCAST(VhostUserState, nc, nc);
> >
> > - /* We don't provide a receive callback */
> > - s->nc.receive_disabled = 1;
> > - s->chr = chr;
> > - s->vhostforce = vhostforce;
> > -
> > - qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event,
> s);
> > + /* We don't provide a receive callback */
> > + s->nc.receive_disabled = 1;
> > + s->chr = chr;
> > + s->vhostforce = vhostforce;
> >
> > + qemu_chr_add_handlers(s->chr, NULL, NULL, net_vhost_user_event,
> s);
> > + }
> > return 0;
> > }
> >
> > @@ -228,6 +230,7 @@ static int net_vhost_check_net(QemuOpts *opts,
> > void *opaque) int net_init_vhost_user(const NetClientOptions *opts,
> const char *name,
> > NetClientState *peer) {
> > + uint32_t queues;
> > const NetdevVhostUserOptions *vhost_user_opts;
> > CharDriverState *chr;
> > bool vhostforce;
> > @@ -254,5 +257,13 @@ int net_init_vhost_user(const NetClientOptions
> *opts, const char *name,
> > vhostforce = false;
> > }
> >
> > - return net_vhost_user_init(peer, "vhost_user", name, chr, vhostforce);
> > + /* number of queues for multiqueue */
> > + if (vhost_user_opts->has_queues) {
> > + queues = vhost_user_opts->queues;
> > + } else {
> > + queues = 1;
> > + }
> > +
> > + return net_vhost_user_init(peer, "vhost_user", name, chr, vhostforce,
> > + queues);
> > }
> > diff --git a/qapi-schema.json b/qapi-schema.json index
> > e16f8eb..c2cead0 100644
> > --- a/qapi-schema.json
> > +++ b/qapi-schema.json
> > @@ -2287,12 +2287,16 @@
> > #
> > # @vhostforce: #optional vhost on for non-MSIX virtio guests (default:
> false).
> > #
> > +# @queues: #optional number of queues to be created for multiqueue
> vhost-user
> > +# (Since 2.3)
> > +#
> > # Since 2.1
> > ##
> > { 'type': 'NetdevVhostUserOptions',
> > 'data': {
> > 'chardev': 'str',
> > - '*vhostforce': 'bool' } }
> > + '*vhostforce': 'bool',
> > + '*queues': 'uint32' } }
> >
> > ##
> > # @NetClientOptions
> > diff --git a/qemu-options.hx b/qemu-options.hx index 85ca3ad..b5fa61f
> > 100644
> > --- a/qemu-options.hx
> > +++ b/qemu-options.hx
> > @@ -1894,13 +1894,14 @@ The hubport netdev lets you connect a NIC to a
> > QEMU "vlan" instead of a single netdev. @code{-net} and
> > @code{-device} with parameter @option{vlan} create the required hub
> automatically.
> >
> > address@hidden -netdev vhost-user,address@hidden,vhostforce=on|off]
> > address@hidden -netdev
> > +vhost-user,address@hidden,vhostforce=on|off][,queues=n]
> >
> > Establish a vhost-user netdev, backed by a chardev @var{id}. The
> > chardev should be a unix domain socket backed one. The vhost-user
> > uses a specifically defined protocol to pass vhost ioctl replacement
> > messages to an application on the other end of the socket. On
> > non-MSIX guests, the feature can be forced with address@hidden
> > address@hidden Use 'address@hidden' to specify the number of
> > +queues to be created for multiqueue vhost-user.
> >
> > Example:
> > @example