Re: [Qemu-devel] [PATCH 10/12] virtio-net: multiqueue support

[Blue Swirl]

On Fri, Jan 4, 2013 at 5:12 AM, Jason Wang <address@hidden> wrote:
> On 12/29/2012 01:52 AM, Blue Swirl wrote:
>> On Fri, Dec 28, 2012 at 10:32 AM, Jason Wang <address@hidden> wrote:
>>> This patch implements both userspace and vhost support for multiple queue
>>> virtio-net (VIRTIO_NET_F_MQ). This is done by introducing an array of
>>> VirtIONetQueue to VirtIONet.
>>>
>>> Signed-off-by: Jason Wang <address@hidden>
>>> ---
>>>  hw/virtio-net.c |  318 
>>> ++++++++++++++++++++++++++++++++++++++++++-------------
>>>  hw/virtio-net.h |   27 +++++-
>>>  2 files changed, 271 insertions(+), 74 deletions(-)
> [...]
>>>  static void virtio_net_handle_ctrl(VirtIODevice *vdev, VirtQueue *vq)
>>>  {
>>>      VirtIONet *n = to_virtio_net(vdev);
>>> @@ -464,6 +578,8 @@ static void virtio_net_handle_ctrl(VirtIODevice *vdev, 
>>> VirtQueue *vq)
>>>              status = virtio_net_handle_mac(n, ctrl.cmd, &elem);
>>>          else if (ctrl.class == VIRTIO_NET_CTRL_VLAN)
>>>              status = virtio_net_handle_vlan_table(n, ctrl.cmd, &elem);
>>> +        else if (ctrl.class == VIRTIO_NET_CTRL_MQ)
>> Please add braces.
>
> Sure.
>>
>>> +            status = virtio_net_handle_mq(n, ctrl.cmd, &elem);
>>>
>>>          stb_p(elem.in_sg[elem.in_num - 1].iov_base, status);
>>>
>>> @@ -477,19 +593,24 @@ static void virtio_net_handle_ctrl(VirtIODevice 
>>> *vdev, VirtQueue *vq)
>>>  static void virtio_net_handle_rx(VirtIODevice *vdev, VirtQueue *vq)
>>>  {
>>>      VirtIONet *n = to_virtio_net(vdev);
>>> +    int queue_index = vq2q(virtio_get_queue_index(vq));
>>>
>>> -    qemu_flush_queued_packets(qemu_get_queue(n->nic));
>>> +    qemu_flush_queued_packets(qemu_get_subqueue(n->nic, queue_index));
>>>  }
>>>
>>>
> [...]
>>>
>>> +static void virtio_net_set_multiqueue(VirtIONet *n, int multiqueue, int 
>>> ctrl)
>>> +{
>>> +    VirtIODevice *vdev = &n->vdev;
>>> +    int i;
>>> +
>>> +    n->multiqueue = multiqueue;
>>> +
>>> +    if (!multiqueue)
>>> +        n->curr_queues = 1;
>> Ditto. Didn't checkpatch.pl catch these or did you not check?
>
> Sorry, will add braces here. I run checkpatch.pl but finally find that
> some or lots of the existed codes (such as this file) does not obey the
> rules. So I'm not sure whether I need to correct my own codes, or left
> them as this file does and correct them all in the future.

The goal is to make QEMU codebase conform to CODING_STYLE. Currently
this is not the case for some amounts of code, but we should use
opportunities like this to advance towards that goal.

>>
> [...]
>>>  } QEMU_PACKED;
>>>
>>>  /* This is the first element of the scatter-gather list.  If you don't
>>> @@ -168,6 +172,26 @@ struct virtio_net_ctrl_mac {
>>>   #define VIRTIO_NET_CTRL_VLAN_ADD             0
>>>   #define VIRTIO_NET_CTRL_VLAN_DEL             1
>>>
>>> +/*
>>> + * Control Multiqueue
>>> + *
>>> + * The command VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET
>>> + * enables multiqueue, specifying the number of the transmit and
>>> + * receive queues that will be used. After the command is consumed and 
>>> acked by
>>> + * the device, the device will not steer new packets on receive virtqueues
>>> + * other than specified nor read from transmit virtqueues other than 
>>> specified.
>>> + * Accordingly, driver should not transmit new packets  on virtqueues 
>>> other than
>>> + * specified.
>>> + */
>>> +struct virtio_net_ctrl_mq {
>> VirtIONetCtrlMQ and please don't forget the typedef.
>
> Sure, but the same question as above. (See other structures in this file).
>>
>>> +    uint16_t virtqueue_pairs;
>>> +};
>>> +
>>> +#define VIRTIO_NET_CTRL_MQ   4
>>> + #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET        0
>>> + #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN        1
>>> + #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX        0x8000
>>> +
>>>  #define DEFINE_VIRTIO_NET_FEATURES(_state, _field) \
>>>          DEFINE_VIRTIO_COMMON_FEATURES(_state, _field), \
>>>          DEFINE_PROP_BIT("csum", _state, _field, VIRTIO_NET_F_CSUM, true), \
>>> @@ -186,5 +210,6 @@ struct virtio_net_ctrl_mac {
>>>          DEFINE_PROP_BIT("ctrl_vq", _state, _field, VIRTIO_NET_F_CTRL_VQ, 
>>> true), \
>>>          DEFINE_PROP_BIT("ctrl_rx", _state, _field, VIRTIO_NET_F_CTRL_RX, 
>>> true), \
>>>          DEFINE_PROP_BIT("ctrl_vlan", _state, _field, 
>>> VIRTIO_NET_F_CTRL_VLAN, true), \
>>> -        DEFINE_PROP_BIT("ctrl_rx_extra", _state, _field, 
>>> VIRTIO_NET_F_CTRL_RX_EXTRA, true)
>>> +        DEFINE_PROP_BIT("ctrl_rx_extra", _state, _field, 
>>> VIRTIO_NET_F_CTRL_RX_EXTRA, true), \
>>> +        DEFINE_PROP_BIT("mq", _state, _field, VIRTIO_NET_F_MQ, true)
>>>  #endif
>>> --
>>> 1.7.1
>>>
>>>
>