On 07/06/2012 04:02 AM, Amos Kong wrote:
On 07/05/2012 06:29 PM, Jason Wang wrote:
This patch converts virtio_net to a multi queue device. After negotiated
VIRTIO_NET_F_MULTIQUEUE feature, the virtio device has many tx/rx queue pairs,
and driver could read the number from config space.
The driver expects the number of rx/tx queue paris is equal to the number of
vcpus. To maximize the performance under this per-cpu rx/tx queue pairs, some
optimization were introduced:
- Txq selection is based on the processor id in order to avoid contending a lock
whose owner may exits to host.
- Since the txq/txq were per-cpu, affinity hint were set to the cpu that owns
the queue pairs.
Signed-off-by: Krishna Kumar<krkumar2@xxxxxxxxxx>
Signed-off-by: Jason Wang<jasowang@xxxxxxxxxx>
---
...
static int virtnet_probe(struct virtio_device *vdev)
{
- int err;
+ int i, err;
struct net_device *dev;
struct virtnet_info *vi;
+ u16 num_queues, num_queue_pairs;
+
+ /* Find if host supports multiqueue virtio_net device */
+ err = virtio_config_val(vdev, VIRTIO_NET_F_MULTIQUEUE,
+ offsetof(struct virtio_net_config,
+ num_queues),&num_queues);
+
+ /* We need atleast 2 queue's */
s/atleast/at least/
+ if (err || num_queues< 2)
+ num_queues = 2;
+ if (num_queues> MAX_QUEUES * 2)
+ num_queues = MAX_QUEUES;
num_queues = MAX_QUEUES * 2;
MAX_QUEUES is the limitation of RX or TX.
Right, it's a typo, thanks.
+
+ num_queue_pairs = num_queues / 2;
...
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