In patch [1], NAPI has been supported in kernel tun driver to accelerate packet processing received from vhost_net. This will greatly improve the throughput of the tap device in the vhost_net backend.
[1]: https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next.git/commit/?id=fb3f903769e8 Signed-off-by: Harold Huang <baymaxhu...@gmail.com> --- drivers/net/virtio/virtio_user/vhost_kernel.c | 9 +++++++-- drivers/net/virtio/virtio_user/vhost_kernel_tap.c | 4 ++-- drivers/net/virtio/virtio_user/vhost_kernel_tap.h | 3 ++- 3 files changed, 11 insertions(+), 5 deletions(-) diff --git a/drivers/net/virtio/virtio_user/vhost_kernel.c b/drivers/net/virtio/virtio_user/vhost_kernel.c index 202a8cdee1..986b56a7ca 100644 --- a/drivers/net/virtio/virtio_user/vhost_kernel.c +++ b/drivers/net/virtio/virtio_user/vhost_kernel.c @@ -383,6 +383,7 @@ vhost_kernel_setup(struct virtio_user_dev *dev) struct vhost_kernel_data *data; unsigned int tap_features; unsigned int tap_flags; + unsigned int r_flags; const char *ifname; uint32_t q, i; int vhostfd; @@ -394,6 +395,10 @@ vhost_kernel_setup(struct virtio_user_dev *dev) PMD_INIT_LOG(ERR, "TAP does not support IFF_VNET_HDR"); return -1; } + r_flags = IFF_TAP | IFF_NO_PI | IFF_VNET_HDR; + + if (tap_features & IFF_NAPI) + r_flags |= IFF_NAPI; data = malloc(sizeof(*data)); if (!data) { @@ -429,7 +434,7 @@ vhost_kernel_setup(struct virtio_user_dev *dev) } ifname = dev->ifname != NULL ? dev->ifname : "tap%d"; - data->tapfds[0] = tap_open(ifname, (tap_features & IFF_MULTI_QUEUE) != 0); + data->tapfds[0] = tap_open(ifname, r_flags, (tap_features & IFF_MULTI_QUEUE) != 0); if (data->tapfds[0] < 0) goto err_tapfds; if (dev->ifname == NULL && tap_get_name(data->tapfds[0], &dev->ifname) < 0) { @@ -446,7 +451,7 @@ vhost_kernel_setup(struct virtio_user_dev *dev) } for (i = 1; i < dev->max_queue_pairs; i++) { - data->tapfds[i] = tap_open(dev->ifname, true); + data->tapfds[i] = tap_open(dev->ifname, r_flags, true); if (data->tapfds[i] < 0) goto err_tapfds; } diff --git a/drivers/net/virtio/virtio_user/vhost_kernel_tap.c b/drivers/net/virtio/virtio_user/vhost_kernel_tap.c index 2aac4028bb..611e2e25ec 100644 --- a/drivers/net/virtio/virtio_user/vhost_kernel_tap.c +++ b/drivers/net/virtio/virtio_user/vhost_kernel_tap.c @@ -42,7 +42,7 @@ tap_support_features(unsigned int *tap_features) } int -tap_open(const char *ifname, bool multi_queue) +tap_open(const char *ifname, unsigned int r_flags, bool multi_queue) { struct ifreq ifr; int tapfd; @@ -61,7 +61,7 @@ tap_open(const char *ifname, bool multi_queue) retry_mono_q: memset(&ifr, 0, sizeof(ifr)); strncpy(ifr.ifr_name, ifname, IFNAMSIZ - 1); - ifr.ifr_flags = IFF_TAP | IFF_NO_PI | IFF_VNET_HDR; + ifr.ifr_flags = r_flags; if (multi_queue) ifr.ifr_flags |= IFF_MULTI_QUEUE; if (ioctl(tapfd, TUNSETIFF, (void *)&ifr) == -1) { diff --git a/drivers/net/virtio/virtio_user/vhost_kernel_tap.h b/drivers/net/virtio/virtio_user/vhost_kernel_tap.h index 726433c48c..636a0481be 100644 --- a/drivers/net/virtio/virtio_user/vhost_kernel_tap.h +++ b/drivers/net/virtio/virtio_user/vhost_kernel_tap.h @@ -22,6 +22,7 @@ #define IFF_NO_PI 0x1000 #define IFF_VNET_HDR 0x4000 #define IFF_MULTI_QUEUE 0x0100 +#define IFF_NAPI 0x0010 /* Features for GSO (TUNSETOFFLOAD). */ #define TUN_F_CSUM 0x01 /* You can hand me unchecksummed packets. */ @@ -36,7 +37,7 @@ int vhost_kernel_tap_setup(int tapfd, int hdr_size, uint64_t features); int tap_support_features(unsigned int *tap_features); -int tap_open(const char *ifname, bool multi_queue); +int tap_open(const char *ifname, unsigned int r_flags, bool multi_queue); int tap_get_name(int tapfd, char **ifname); int tap_get_flags(int tapfd, unsigned int *tap_flags); int tap_set_mac(int tapfd, uint8_t *mac); -- 2.27.0
