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Re: [Qemu-devel] [PATCH v2] vhost-user: add multi queue support
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v2] vhost-user: add multi queue support |
Date: |
Mon, 6 Apr 2015 17:07:15 +0200 |
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;
> 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
- Re: [Qemu-devel] [PATCH v2] vhost-user: add multi queue support,
Michael S. Tsirkin <=