similar to: [PATCH] virtio-net: put virtio net header inline with data

Thinking about Sasha's patches, we can reduce ring usage for virtio net small packets dramatically if we put virtio net header inline with the data. This can be done for free in case guest net stack allocated extra head room for the packet, and I don't see why would this have any downsides. Even though with my recent patches qemu no longer requires header to be the first s/g element, we

Thinking about Sasha's patches, we can reduce ring usage for virtio net small packets dramatically if we put virtio net header inline with the data. This can be done for free in case guest net stack allocated extra head room for the packet, and I don't see why would this have any downsides. Even though with my recent patches qemu no longer requires header to be the first s/g element, we

From: Rusty Russell <rusty at rustcorp.com.au> Date: Tue, 09 Jul 2013 17:38:51 +0930 > If you convince DaveM, I won't object :) Simplifications are great, but not when the merge window opens up. Sorry, this isn't appropriate now.

From: Rusty Russell <rusty at rustcorp.com.au> Date: Tue, 09 Jul 2013 17:38:51 +0930 > If you convince DaveM, I won't object :) Simplifications are great, but not when the merge window opens up. Sorry, this isn't appropriate now.

virtio 1.0 doesn't use virtio_net_hdr anymore, and in fact, it's not really useful since virtio_net_hdr_mrg_rxbuf includes that as the first field anyway. Let's drop it, precalculate header len and store within vi instead. This way we can also remove struct skb_vnet_hdr. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at

virtio 1.0 doesn't use virtio_net_hdr anymore, and in fact, it's not really useful since virtio_net_hdr_mrg_rxbuf includes that as the first field anyway. Let's drop it, precalculate header len and store within vi instead. This way we can also remove struct skb_vnet_hdr. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Reviewed-by: Cornelia Huck <cornelia.huck at

Too many places poke at [rs]q->vq->vdev->priv just to get the the vi structure. Let's just pass the pointer around: seems cleaner, and might even be faster. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/net/virtio_net.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) diff --git a/drivers/net/virtio_net.c

Too many places poke at [rs]q->vq->vdev->priv just to get the the vi structure. Let's just pass the pointer around: seems cleaner, and might even be faster. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/net/virtio_net.c | 36 +++++++++++++++++++----------------- 1 file changed, 19 insertions(+), 17 deletions(-) diff --git a/drivers/net/virtio_net.c

On 06/06/2013 05:55 PM, Michael S. Tsirkin wrote: > For small packets we can simplify xmit processing by linearizing buffers > with the header: most packets seem to have enough head room we can use > for this purpose. > > Since some older hypervisors (e.g. qemu before version 1.5) > required that header is the first s/g element, > we need a feature bit for this. > >

On Thu, Nov 02, 2017 at 11:40:36AM +0000, Ilya Lesokhin wrote: > Hi, > I've noticed that the virtio-net uses skb->cb. > > I don't know all the detail by my understanding is it caused problem with the mlx5 driver > and was fixed here: > https://github.com/torvalds/linux/commit/34802a42b3528b0e18ea4517c8b23e1214a09332 > > Thanks, > Ilya Thanks a lot for the

On Thu, Nov 02, 2017 at 11:40:36AM +0000, Ilya Lesokhin wrote: > Hi, > I've noticed that the virtio-net uses skb->cb. > > I don't know all the detail by my understanding is it caused problem with the mlx5 driver > and was fixed here: > https://github.com/torvalds/linux/commit/34802a42b3528b0e18ea4517c8b23e1214a09332 > > Thanks, > Ilya Thanks a lot for the

virtio 1.0 doesn't use virtio_net_hdr anymore, and in fact, it's not really useful since virtio_net_hdr_mrg_rxbuf includes that as the first field anyway. Let's drop it, precalculate header len and store within vi instead. This way we can also remove struct skb_vnet_hdr. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/net/virtio_net.c | 90

virtio 1.0 doesn't use virtio_net_hdr anymore, and in fact, it's not really useful since virtio_net_hdr_mrg_rxbuf includes that as the first field anyway. Let's drop it, precalculate header len and store within vi instead. This way we can also remove struct skb_vnet_hdr. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- drivers/net/virtio_net.c | 90

From: Michael S. Tsirkin <mst at redhat.com> For small packets we can simplify xmit processing by linearizing buffers with the header: most packets seem to have enough head room we can use for this purpose. Since existing hypervisors require that header is the first s/g element, we need a feature bit for this. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> Signed-off-by: Rusty

For small packets we can simplify xmit processing by linearizing buffers with the header: most packets seem to have enough head room we can use for this purpose. Since existing hypervisors require that header is the first s/g element, we need a feature bit for this. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- Note: this needs to be applied on top of patch defining

For small packets we can simplify xmit processing by linearizing buffers with the header: most packets seem to have enough head room we can use for this purpose. Since existing hypervisors require that header is the first s/g element, we need a feature bit for this. Signed-off-by: Michael S. Tsirkin <mst at redhat.com> --- Note: this needs to be applied on top of patch defining

multiple queue virtio-net: flow steering through host/guest cooperation Hello all: This is a rough series adds the guest/host cooperation of flow steering support based on Krish Kumar's multiple queue virtio-net driver patch 3/3 (http://lwn.net/Articles/467283/). This idea is simple, the backend pass the rxhash to the guest and guest would tell the backend the hash to queue mapping when

multiple queue virtio-net: flow steering through host/guest cooperation Hello all: This is a rough series adds the guest/host cooperation of flow steering support based on Krish Kumar's multiple queue virtio-net driver patch 3/3 (http://lwn.net/Articles/467283/). This idea is simple, the backend pass the rxhash to the guest and guest would tell the backend the hash to queue mapping when

The virtio_net driver's mergeable receive buffer allocator uses 4KB packet buffers. For MTU-sized traffic, SKB truesize is > 4KB but only ~1500 bytes of the buffer is used to store packet data, reducing the effective TCP window size substantially. This patch addresses the performance concerns with mergeable receive buffers by allocating MTU-sized packet buffers using page frag allocators.

The virtio_net driver's mergeable receive buffer allocator uses 4KB packet buffers. For MTU-sized traffic, SKB truesize is > 4KB but only ~1500 bytes of the buffer is used to store packet data, reducing the effective TCP window size substantially. This patch addresses the performance concerns with mergeable receive buffers by allocating MTU-sized packet buffers using page frag allocators.