similar to: [PATCH 5/6] virtio_net: rework mergeable buffer handling

Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag allocators") changed the mergeable receive buffer size from PAGE_SIZE to MTU-size, introducing a single-stream regression for benchmarks with large average packet size. There is no single optimal buffer size for all workloads. For workloads with packet size <= MTU bytes, MTU + virtio-net header-sized buffers

For small packets data copy was observed to take up about 15% CPU time. Switch to build_skb and avoid the copy when using mergeable rx buffers. As a bonus, medium-size skbs that fit in a page will be completely linear. Of course, we now need to lower the lower bound on packet size, to make sure a sane number of skbs fits in rx socket buffer. By how much? I don't know yet. It might also be

For small packets data copy was observed to take up about 15% CPU time. Switch to build_skb and avoid the copy when using mergeable rx buffers. As a bonus, medium-size skbs that fit in a page will be completely linear. Of course, we now need to lower the lower bound on packet size, to make sure a sane number of skbs fits in rx socket buffer. By how much? I don't know yet. It might also be

Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag allocators") changed the mergeable receive buffer size from PAGE_SIZE to MTU-size, introducing a single-stream regression for benchmarks with large average packet size. There is no single optimal buffer size for all workloads. For workloads with packet size <= MTU bytes, MTU + virtio-net header-sized buffers

The virtio-net driver currently uses netdev_alloc_frag() for GFP_ATOMIC mergeable rx buffer allocations. This commit migrates virtio-net to use per-receive queue page frags for GFP_ATOMIC allocation. This change unifies mergeable rx buffer memory allocation, which now will use skb_refill_frag() for both atomic and GFP-WAIT buffer allocations. To address fragmentation concerns, if after buffer

On Wed, Nov 13, 2013 at 03:10:20PM +0800, Jason Wang wrote: > On 11/13/2013 06:21 AM, Michael Dalton wrote: > > Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag > > allocators") changed the mergeable receive buffer size from PAGE_SIZE to > > MTU-size, introducing a single-stream regression for benchmarks with large > > average packet

On Mon, Oct 28, 2013 at 10:44 PM, Michael Dalton <mwdalton at google.com> wrote: > 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

Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag allocators") changed the mergeable receive buffer size from PAGE_SIZE to MTU-size, introducing a single-stream regression for benchmarks with large average packet size. There is no single optimal buffer size for all workloads. For workloads with packet size <= MTU bytes, MTU + virtio-net header-sized buffers

On 11/13/2013 12:21 AM, Michael Dalton wrote: > Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag > allocators") changed the mergeable receive buffer size from PAGE_SIZE to > MTU-size, introducing a single-stream regression for benchmarks with large > average packet size. There is no single optimal buffer size for all workloads. > For workloads

On 11/13/2013 12:21 AM, Michael Dalton wrote: > Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag > allocators") changed the mergeable receive buffer size from PAGE_SIZE to > MTU-size, introducing a single-stream regression for benchmarks with large > average packet size. There is no single optimal buffer size for all workloads. > For workloads

Pack headroom into ctx, then during XDP set, we could know the size of headroom and copy if needed. This is required for avoiding reset on XDP. Signed-off-by: Jason Wang <jasowang at redhat.com> --- drivers/net/virtio_net.c | 29 ++++++++++++++++++++++++----- 1 file changed, 24 insertions(+), 5 deletions(-) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index

On Mon, Jul 17, 2017 at 08:43:58PM +0800, Jason Wang wrote: > Pack headroom into ctx, then during XDP set, we could know the size of > headroom and copy if needed. This is required for avoiding reset on > XDP. Not really when XDP is set - it's when buffers are used. virtio-net: pack headroom into ctx for mergeable buffers Pack headroom into ctx - this way when we get a buffer we

On Mon, Jul 17, 2017 at 08:43:58PM +0800, Jason Wang wrote: > Pack headroom into ctx, then during XDP set, we could know the size of > headroom and copy if needed. This is required for avoiding reset on > XDP. Not really when XDP is set - it's when buffers are used. virtio-net: pack headroom into ctx for mergeable buffers Pack headroom into ctx - this way when we get a buffer we

The virtio-net driver currently uses netdev_alloc_frag() for GFP_ATOMIC mergeable rx buffer allocations. This commit migrates virtio-net to use per-receive queue page frags for GFP_ATOMIC allocation. This change unifies mergeable rx buffer memory allocation, which now will use skb_refill_frag() for both atomic and GFP-WAIT buffer allocations. To address fragmentation concerns, if after buffer

On 01/07/2014 01:25 PM, Michael Dalton wrote: > Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag > allocators") changed the mergeable receive buffer size from PAGE_SIZE to > MTU-size, introducing a single-stream regression for benchmarks with large > average packet size. There is no single optimal buffer size for all > workloads. For workloads

On 01/07/2014 01:25 PM, Michael Dalton wrote: > Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag > allocators") changed the mergeable receive buffer size from PAGE_SIZE to > MTU-size, introducing a single-stream regression for benchmarks with large > average packet size. There is no single optimal buffer size for all > workloads. For workloads

On Mon, Jan 06, 2014 at 09:25:54PM -0800, Michael Dalton wrote: > Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag > allocators") changed the mergeable receive buffer size from PAGE_SIZE to > MTU-size, introducing a single-stream regression for benchmarks with large > average packet size. There is no single optimal buffer size for all >

On Mon, Jan 06, 2014 at 09:25:54PM -0800, Michael Dalton wrote: > Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag > allocators") changed the mergeable receive buffer size from PAGE_SIZE to > MTU-size, introducing a single-stream regression for benchmarks with large > average packet size. There is no single optimal buffer size for all >

The virtio-net driver currently uses netdev_alloc_frag() for GFP_ATOMIC mergeable rx buffer allocations. This commit migrates virtio-net to use per-receive queue page frags for GFP_ATOMIC allocation. This change unifies mergeable rx buffer memory allocation, which now will use skb_refill_frag() for both atomic and GFP-WAIT buffer allocations. To address fragmentation concerns, if after buffer

On 11/13/2013 06:21 AM, Michael Dalton wrote: > Commit 2613af0ed18a ("virtio_net: migrate mergeable rx buffers to page frag > allocators") changed the mergeable receive buffer size from PAGE_SIZE to > MTU-size, introducing a single-stream regression for benchmarks with large > average packet size. There is no single optimal buffer size for all workloads. > For workloads