This patch adds the multiqueue (VIRTIO_NET_F_MQ) support to virtio_net driver. VIRTIO_NET_F_MQ capable device could allow the driver to do packet transmission and reception through multiple queue pairs and does the packet steering to get better performance. By default, one one queue pair is used, user could change the number of queue pairs by ethtool in the next patch. When multiple queue pairs is used and the number of queue pairs is equal to the number of vcpus. Driver does the following optimizations to implement per-cpu virt queue pairs: - select the txq based on the smp processor id. - smp affinity hint to the cpu that owns the queue pairs. This could be used with the flow steering support of the device to guarantee the packets of a single flow is handled by the same cpu.
Showing the changes to include/uapi/linux (1 of 2 files). Show all
Unified · Split
| @@ -51,6 +51,8 @@ · 50 unmodified lines | |||
| 51 | #define VIRTIO_NET_F_CTRL_RX_EXTRA 20 /* Extra RX mode control support */ | 51 | #define VIRTIO_NET_F_CTRL_RX_EXTRA 20 /* Extra RX mode control support */ |
| 52 | #define VIRTIO_NET_F_GUEST_ANNOUNCE 21 /* Guest can announce device on the | 52 | #define VIRTIO_NET_F_GUEST_ANNOUNCE 21 /* Guest can announce device on the |
| 53 | * network */ | 53 | * network */ |
| 54 | #define VIRTIO_NET_F_MQ 22 /* Device supports Receive Flow | ||
| 55 | * Steering */ | ||
| 54 | 56 | ||
| 55 | #define VIRTIO_NET_S_LINK_UP 1 /* Link is up */ | 57 | #define VIRTIO_NET_S_LINK_UP 1 /* Link is up */ |
| 56 | #define VIRTIO_NET_S_ANNOUNCE 2 /* Announcement is needed */ | 58 | #define VIRTIO_NET_S_ANNOUNCE 2 /* Announcement is needed */ |
| @@ -60,6 +62,11 @@ struct virtio_net_config { · 3 unmodified lines | |||
| 60 | __u8 mac[6]; | 62 | __u8 mac[6]; |
| 61 | /* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */ | 63 | /* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */ |
| 62 | __u16 status; | 64 | __u16 status; |
| 65 | /* Maximum number of each of transmit and receive queues; | ||
| 66 | * see VIRTIO_NET_F_MQ and VIRTIO_NET_CTRL_MQ. | ||
| 67 | * Legal values are between 1 and 0x8000 | ||
| 68 | */ | ||
| 69 | __u16 max_virtqueue_pairs; | ||
| 63 | } __attribute__((packed)); | 70 | } __attribute__((packed)); |
| 64 | 71 | ||
| 65 | /* This is the first element of the scatter-gather list. If you don't | 72 | /* This is the first element of the scatter-gather list. If you don't |
| @@ -166,4 +173,24 @@ struct virtio_net_ctrl_mac { · 100 unmodified lines | |||
| 166 | #define VIRTIO_NET_CTRL_ANNOUNCE 3 | 173 | #define VIRTIO_NET_CTRL_ANNOUNCE 3 |
| 167 | #define VIRTIO_NET_CTRL_ANNOUNCE_ACK 0 | 174 | #define VIRTIO_NET_CTRL_ANNOUNCE_ACK 0 |
| 168 | 175 | ||
| 176 | /* | ||
| 177 | * Control Receive Flow Steering | ||
| 178 | * | ||
| 179 | * The command VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET | ||
| 180 | * enables Receive Flow Steering, specifying the number of the transmit and | ||
| 181 | * receive queues that will be used. After the command is consumed and acked by | ||
| 182 | * the device, the device will not steer new packets on receive virtqueues | ||
| 183 | * other than specified nor read from transmit virtqueues other than specified. | ||
| 184 | * Accordingly, driver should not transmit new packets on virtqueues other than | ||
| 185 | * specified. | ||
| 186 | */ | ||
| 187 | struct virtio_net_ctrl_mq { | ||
| 188 | u16 virtqueue_pairs; | ||
| 189 | }; | ||
| 190 | |||
| 191 | #define VIRTIO_NET_CTRL_MQ 4 | ||
| 192 | #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET 0 | ||
| 193 | #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN 1 | ||
| 194 | #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX 0x8000 | ||
| 195 | |||
| 169 | #endif /* _LINUX_VIRTIO_NET_H */ | 196 | #endif /* _LINUX_VIRTIO_NET_H */ |